• English comments
• Midi implementation
• Tech Specs
• Repertoire
• Maintenance manual
• Nederlandstalige versie

Technical Description

A computer controlled 6-octave reed organ with touch control, swells and individual registration. The starting point for this construction was an old Emile Kerkhoff (1887-1956) suction reed organ, of which we only kept the reeds and the key springs. A new electric compressor was added (a small Laukhuff Ventola, rated for 80mm H2O pressure (800 Pa) and 3000 l/min) replacing the bellows. The instrument has 4 sets of reeds for the bass side and 4 sets of reeds on the treble side. In addition it is equipped with 1 octave (13 reeds) of reeds for a subbass. These sound the notes 12 -24. The picture shows the note valves for this subbass with the box resonator removed. Taking the registers into account, the real sounding ambitus ranges from midi note 12 to 113, or an impressive eight and a half octaves!

Two swells are provided, as well as a reflective tremulant mechanism. In total the organ has 305 reeds. Although the instrument is signed and labeled Kerkhoff, we have doubts with regard to the real builder. It may very well be an American made Beckwith reed organ (Type: Grand Orchestral Action G, 6 octaves 18 stops). Embossed in the back of the triplex soundboard, it carries the series number 54938.

As usual in our automated instrument designs, we designed a sturdy welded frame made in stainless steel for the entire magnet and electromechanical assembly. As a reminder: we favor AISI304 stainless steel not only for its visual qualities and freedom of maintenance, but also because it is a nonmagnetic material. Other than in our first robot reed organ, here we decided to leave the original keyboard in place. As a consequence, it becomes possible to play the organ in the traditional way even in combination with automated playing. For registration and expression control however, we did not foresee a manual alternative. We used tubular solenoids, 20mm in diameter, to activate the keys here serving as levers to reduce the required force to push the pallets down. This saved us the work of replacing all pallet springs with lighter ones as we did in <Harma>. Since the magnets are wider then the distance between keys/pallets (13.5mm), we had to mount them on alternating rows. This became another reason for not activating the pallets directly. The eight registers are each divided in a bass and a discant unit. So we provided also control for these 8 registers. Although we first wanted to implement this using solenoids with variable voltage , such that gradual changes ('expression') would become possible, some experimentation revealed that the small benefit was not worth the effort and increase in complexity. Gradual opening of the register shutters did just not produce the expected result. However, gradual opening of the dynamic shutters appeared to be an interesting feature worth implementing. Our first attempt using soft shift linear solenoids to this end were not successful because these solenoids did not produce enough pulling force to guarantee a smooth action. Therefore we finally decided to use linear stepper motors with a threaded shaft. This approach makes a smooth action possible at the expense however, of some extra noise caused by the audible stepping frequency. Although this mechanism is relatively low in action, the big advantage of it is that it draws no current to keep position, but only so on movement. The whole traject from closed to fully opened takes about 500ms.

The design of the tremulant was quite adventurous in some respects. At first it appeared that we had about four options:

• 1. Leaving the original pneumatic motor driven mechanism in place and switching it on/off using a solenoid.
• 2. Using a 35mm Laukhuff pallet valve mounted right on the whole in the windchest.
• 3. Using a softshift solenoid driving a conical valve.
• 4. Using a solenoid driven bellow to modulate air pressure.
  
  The first solution, although the easiest one, suffers from the fact that the speed of rotation of the tremulant becomes a function of wind pressure and thus cannot be controlled independently. Also the mechanism tends to be shaky, fragile and causes some noise.
  The second solution - very easy to implement- works pretty well but suffers from a rather square wave like behavior. Also, when the valve is opened, the air flowing in makes quite some noise.
  The third solution requires the construction of a very well machined conical valve with a traject of 10 mm. Its operation becomes as smooth as one wishes since it becomes possible to steer it with a very low frequency sine wave of variable amplitude. Of course other wave forms would lead to different amplitude modulation envelopes.
  The fourth solution leads to the best results. When a large loudspeaker -a powerful woofer- is used as a bellow, the pressure in the windchest can be modulated even at very fast rates. However, the compressed volume should be in a reasonable proportion to that of the entire windchest, thus dictating the use of a speaker with a diameter of some 30 cm. This would make the instrument much larger than what we had in mind. The same size argument does apply to the solution using a solenoid driven bellow.
• Softshift tremulant.
• As soon as we tried the second and third options (shown on the picture above), we discovered that neither of them worked. Mounting the original pneumatic mechanism, however worked fine... Clearly we made a fundamental mistake in the way we understood the function of the tremulant. Rather than working on modulation of the air pressure in the windchest -as usual in pipe organs- , it worked merely on acoustic reflection of the sound on the large cardboard blades of the rotator. In fact it makes use of the Doppler effect to create a slight but real vibrato. Therefore we had to redesign the mechanism completely, and since we wanted to have autonomous control over the modulation frequency, we needed to build a reflector mechanism driven by a variable speed motor. The use of a simple low power stepper, as used for the vibrato drivers on our <Vibi> robot came into our mind, as these run really silently..
  

<HarmO> is controlled by no less than 13 PIC microcontrollers (6 for the notes and the registers, 3 for the linear stepper motor controllers, 2 for the compressor motor, 1 for the lights, the motor control signals and the tremulant) and takes midi input directly. Of course the instrument can play standard midi files. <HarmO> was designed from the beginning on with velocity control, based on precise timing of an initial high voltage pulse to activate the note solenoids. The effect of velocity control or touch sensitivity is of course by far less effective than it is on our player piano or on the organs equipped with conical windchest valves such as <Bomi>. The speed wherewith the valves open in a reed organ being generally much faster than the rather slow build up of a sound from the reeds. However, any touch sensitivity a reed organ played by a human might have, is also implemented and at least surpassed in this robot. In fact in this robot reed organ, we realized a major improvement over the first similar but smaller reed organ robot, <Harma>. The fact that this robot is tuned to 440Hz, rather than the 435Hz on <Harma>, makes it more suitable for integration in our robot orchestra.

In 2015 we added a new feature to the wind regulation mechanism: it now is 'intelligent' in that it will automatically adapt windflow to to notes affectively played as well as to registers drawn and volume setting requested. It is no longer possible for users to make the mistake to let the motor turn at full speed (high volume setting) when no notes are being played. The firmware for the wind motor control was revised a few times, the last revision is dated 27.11.2022.

The circuit overview looks like this:

Circuit details as well as a very detailed building log can be found in the service manual at the very end of this page.

Design and construction:

• dr.Godfried-Willem Raes

Collaborators:

• Kristof Lauwers, GMT coding
• Yvan Vander Sanden
• Moniek Darge
• Troy Rogers, construction assistence (Fullbright PhD student, Virginia University)
• Irs.Johannes Taelman, microcode PIC's.

Nederlands

<HarmO>

Tessituur: 29 (Fa) - 101 (Fa) [ 6oktaven ]

Hiervoor werd uitgegaan van een oud harmonium -volgens het label althans- gebouwd door Emile Kerkhoff, een ambachtelijk wat aan lager wal geraakte orgelbouwer gevestigd in Brussel. De gehele bouw lijkt als twee druppels water op een Beckwith instrument, type 'Grand Orchestral Action G, 6 octaves 18 stops'. Wellicht heeft Kerkhoff niet veel meer zelf gebouwd dan de kast rond het instrument... Het instrument is voorzien van acht onafhankelijke reeksen doorslaande tongen en werkt met zuiglucht, zoals het gros van de naar Amerikaans model gemaakte 'reed organs'. Vier registers voor de bas en vier voor de diskant. Als extra is het harmonium uitgerust met een subbasregister bestaande uit 13 rieten geplaatst in een afzonderlijke bakje dat als resonator dienst doet. Rekening houdend met de registers, strekt de eigenlijke muzikale tessituur van dit instrument zich uit over acht en een half oktaaf (12-113). De balgen en windlade verwijderden we integraal en werden vervangen door een kompressor met motorbesturing, een Laukhuff Ventola zuigblazer. (3000 l/minuut, bij -80 mm H2O druk). Daar dienden we wel een goede geluidsdemper voor te ontwerpen want geruisloos zijn deze Ventola blazers bepaald niet...

De kracht vereist om de paletten rechtstreeks, dus zonder de hefboom gevormd door de toets en het eigen gewicht van de toets, in te drukken maten we als 2.45 Newton (250 gF). Bij de bouw van <Harma>, ons eerste robot harmonium, hadden we de kracht van de veren ongeveer gehalveerd teneinde kleine Laukhuff elektromagneten te kunnen toepassen. Het nadeel van dat opzet was dat het instrument makkelijk neiging heeft tot lekken wanneer druk in de lade wordt opgebouwd zonder dat noten gespeeld worden. Dit euvel wilden we hier vermijden. Buisvormige elektromagneten met een diameter niet groter dan 13mm (wat vereist zou zijn om de magneten uitgelijnd met de paletduwers te plaatsen) en een dergelijke kracht (2.45 N) worden niet gefabriceerd. Daarom maten we de kracht nodig om de toetsen in te drukken en kwamen uit op 1.2 tot 1.5 Newton. Heel wat minder dus, wat uiteraard te wijten is aan de werking als hefboom en aan het eigengewicht van de toetsen.

Hartafstand tussen de bedieningspallen voor de rieten was 13.54mm, waardoor we de magneten om en om (in twee rijen) dienden te monteren. Wanneer we de bedieningsmagneten om en om monteren, mogen ze dan hooguit 27mm breed zijn. De gebruikte types zijn 20mm breed. Voor deze montage plooiden we een inox plaat van 2 mm dikte in een assymetrische U-vorm. In de onderzijde daarvan werden de 73 gaten voor de montage van de elektromagneten geboord. Om de automaat goed te kunnen afregelen, werd de gehele elektromagnetendrager zo gemonteerd op de zijdelingse steunen, dat de hoogte ligging heel nauwkeurig kan worden ingesteld.

De registers zijn telkens gedeeld in bas- en diskant. Voor de automatisering daarvan gebruikten we elektromagneten met dubbele spoelen van de firma Laukhuff. Er zijn 4 registers aan de baskant en 4 aan de sopraankant. Daarbovenop komt nog het subbasregister. Voor de automatisering van de zwelkasten, werden twee lineaire stappenmotoren van Nanotec toegepast. De toepassing van soft-shift lineaire magneten hadden we oorspronkelijk voorzien, maar daarvan dienden we uiteindelijk af te zien vanwege de te geringe kracht die deze komponenten kunnen leveren (8 tot 13 Newton, terwijl we eigenlijk meer dan het dubbele nodig bleken te hebben). Bovendien vormde ook het vermogen nodig om een bepaalde positie aan te houden (21 Watt) een bezwaar. Lineare stappenmotoren met een schroefgang-as houden hun positie wanneer ze volledig stroomloos worden gemaakt. De snelheid van deze mechanismen is echter heel wat lager dan bij soft-shift magneten. Het hele trajekt met de lineaire motoren neemt ca. 500ms in beslag, terwijl dit bij toepassing van soft-shift magneten slechts 45ms zou duren.

De radiale kompressor is voorzien van een regelschuif, gemonteerd aan de inlaat van de windlade. Deze regelschuif werd eveneens geautomatiseerd en daarvoor ontwierpen we een mekanisme met een stappenmotor en een getande riem. Hierdoor wordt een snellere regeling (ca. 200ms voor het gehele trajekt) van de winddruk mogelijk dan wat voorzien is via sturing van het toerental van de motor zelf. De windregelschuif werd gemapt op midi kontroller nr.1, terwijl de motor snelheid gestuurd kan worden middels midi kontroller 7.

Voor de elektronische besturingen van de toonkleppen gebruikten we onze eigen en beproefde ontwerpen voor muziekautomaten, meer in het bijzonder, de schakelingen ontwikkeld voor onze player pianos en later in talloze andere robots toegepast. Daardoor kon ook aanslaggevoeligheid worden geimplementeerd. Hoogst ongebruikelijk voor een harmonium, maar we hadden het al eerder gedaan bij de bouw van <Harma>, <Qt>, <Bomi> en <Bako>. <HarmO> kan rechtstreeks via midi zowel als UDP/IP worden aangestuurd. Ook de winddruk is heel nauwkeurig regelbaar, waardoor crescendos perfekt mogelijk zijn. Dit effekt is trouwens op een andere wijze ook te bereiken door gebruik te maken van de beide eerder genoemde zwellers.

Een klein grapje hebben we onszelf bij de bouw van deze automaat toch gepermiteerd: een klopgeest werd ingebouwd... Ook die klopgeest kan via midi kommandos aan de praat worden gebracht.

Niet minder dan dertien mikroprocessoren, elk voorzien van eigen en onderling verschillende firmware, staan in voor de interne besturingen van de diverse onderdelen van deze robot.

Tot de revizie die <HarmO> onderging in 2015 dienden komponisten die voor deze robot wilden schrijven er terdege mee rekening houden dat de winddruk geregeld moest worden in funktie van de gewenste dynamiek enerzijds, maar ook in funktie van het luchtverbruik. We dienden er telkens wee op te wijzen dat het luchtverbruik voor lage tonen heel wat groter is dan voor de hoge. De vroeger meest voorkomende fout in midi bestanden, bestond erin de druk bij aanvang van de track of partij in te stellen op een vaste waarde. Hierdoor echter werd druk opgebouwd zonder rekening te houden met het al dat niet spelen van tonen. Dit leidde niet alleen tot volkomen overbodig lawaai van de motor, maar ook vaak tot lekken in de toonkancellen. De enige goede metode bestond erin, na het inbrengen van de muzikale partij, de windkontroller instellingen (nr.7) voor de gehele track te bepalen in funktie van de notentekst en de gewenste dynamiek en expressie. In 2015 evenwel voegden we een microprocessor toe in <HarmO> die de motorsturing volledig afhankelijk maakt van het effektieve luchtverbruik en van het gewenste volume. Een aantal extra midi controllers werden aan de implementatie toegevoegd. De meeste recente upgrade van de firmware voor deze functie werd uitgevoerd op 27.11.2022.

Repertoire (all repertoire playable on <Harma> can also be played on <HarmO>:

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Service manual & detailed circuit and maintenance documentation

Following information and documentation is not intended for the general public.

Radial compressor: August Laukhuff, Ventola type 612380. Motor 130 Watt, aussenlaufer. Star connected for 3-phase operation with Siemens motorcontroller. Windpressure 800 Pa, 3000 l/min when operated on 50 Hz. Rotation speed at 50Hz: 2800 rmp. Machine number: 6082-8129. Price: 1.309,12 Euro (11/2009)

Tubular solenoids (73): Black Knight 121-420-620-620 (100% duty cycle voltage 12V, diameter 20mm, push type). Resistance: 20ω

Register solenoids (8): Aug.Laukhuff Trakturmagnet, 300810, 24V (10 Newton, 10mm traject) Price: 39,86 Euro (11/2009)

Subbass register solenoids (2): Aug.Laukhuff Ventilmagnet, 24V

Linear stepper motors (2): Nanotec L5609X2008- M6x0.5 (Farnell order nr.: 474-3234). Shaft: ZSM6-0.5-200 spindle, M6x0.5 (Farnell order nr.: 837-5682). Corresponding motor controllers: Nanotec SMC42-2,0-1 (Farnell order nr.: 474-3131). Wiring details:

Windvalve inlet motor: Burroughs Sonceboz type nr. 1251 0228, rated 0.6A/phase and 0.5 Ohms/phase. Bipolar stepper motor. Dented belt: 78mm length, Gates powergrip. Connected to the 24V power, the motor draws 1.2A when running with a 186Hz clock. At 240Hz, it draws 840 mA. This seems to be the optimum clock frequency for this motor.

Doppler tremulant motor: Canon, 6V type R17CN-EQCB, diameter 41mm, fully screened, made in Taiwan.

Circuit boards overview:

Power supply:

2 Siemens Sitop Smart 24 V/10 A, nr.6EP1334-2AA01 (Output voltage adjustable from 22.8 to 28 V) Farnell order nr.: 121-6632

1 Mascot 8921 12 V PSU, desktop 290 W, 20A ( http://www.mascot.no ) Farnell order nr.: 118-3937

1 5 V/ 1 A, encapsulated module.VxI 14438/000 (http://www.vxipower.com). Farnell order nr.: 118-6397

3 analog panel meters are provided for power supply monitoring. Therefore Kyuritsu KM-48 voltmeters, rated 10 V DC, are used. For monitoring the 12 V, a 1% series resistor of 5 k was used such that a reading of 8 V on the original scale now corresponds to 12 V. For the two 24 V supplies, the 1% series resistor becomes 20 k. The meters Ri being 10 k and sensitivity 1 mA.

6 boards for the note pallets:

All note solenoids have a common positive voltage connection. The second wires come together in Weidmueller 6-pole connectors (one for each set) to the note/velo boards. To get access to the reeds and the springs, first disconnect all these connectors. Next, remove the U-shaped stainless steel protectors. Then loosen the bolts joining upper and lower part of the instrument. The solenoid assembly, the vorsetzer, can be lifted up vertically from the soundboard containing the reeds. Always keep components in a horizontal position! When the vorsetzer is taken out, always take care to place it on two stand off blocks such that the mechanism never comes to rest on the solenoid pushers.

The positive voltage can be adjusted on the power supply (Mascot) printed circuit board with the multiturn trimmer. The voltage should be adjusted such that when no velocity pulses are applied, the solenoids develop just enough force to hold the keys down. Initially we found 8V to be a suitable minimum setting. The maximum allowable voltage here is +12V. The negative voltage (the first Sitop power supply) should be adjusted between 20V and 28Volts. Initially we had it set to 24V. Changing this voltage will change the velocity scaling of the instrument. The second Sitop power supply is adjusted to 24V positive and feeds the stepping motors.

The circuitry on the midi input board and the PIC with the motor control worked out like this:

Wiring tables for the six PIC 18F4620 controller boards:

Board 1:

Board 2:

Board 3:

Board 4:

Board 5:

Board 6:

Detail of the three different ways these boards are populated, depending on the functionality:

Board 7 - Midi-hub board: (PIC 18F2525), board version 2006.This board originally controled the radial compressor motor, now it does the swell motors and the tremulant DC-motor. The board is mount under the windchest on a piece of polycarbonate.

Board 8 - Pulse board (PIC 18F2525) [board version rev.3, april 2005, modif..21.12.2009]

This board controls the ghost beaters, the windslide (ctrl.1), the ghost beaters and the lites. This board is located on the same polycarbonate plate as the midi-hub board and is located in the back of the mains power entry. The board did in its original design not have a programming connector, but in this version we constructed a 'flying' 6-pin connector such that in circuit debugging and programming becomes possible as for all other processor boards in <harmO>.

The 'flying' connector for in circuit debugging and programming is shown in the picture below:

Power supplies:

• +12V dc (positive hold voltage): 20A, 260 Watt - SMPS power supply (Mascot)
• - 24V dc (negative pulse voltage): 10A Sitop (Siemens)
• +24V dc (register solenoids, stepper motors): 10A Sitop (Siemens)
• +5V dc logic power, 2A (Encapsulated module)

Programming information and settings for the Siemens Sinamics G110 motor controller:

With these settings we obtain the following midi correspondence:

Note that when no notes are being played, wind pressure should always be reduced to the smallest practical value. Also, required wind pressure is a function of the number of notes playing as well as of their pitch, since lower reeds require a lot more wind than the high ones. With wind pressures higher than midi value 60, leaks can occur when no notes are played. Since 2015 all these problems have been adressed with a new intelligent motor controller. The remarks are still valid, but are now solved in the firmware.

Metal parts sizing and drawings:

View from the bass side:

Lights:

• Five frontal yellow lights: 1W high power LED reflectors. Lifetime: 50000h. GU5.3 socket, view angle 25 degrees, diameter 50mm. Voltage 12V. Forward current 350 mA. Operating temperature:-40C to +80C. Type: HomeStar 574568. Source: Conrad.
• White LED spotlight on the bottom: QRB111. Voltage 230V ac. Switched with a solid state relay. Lamp base: GU10. As a replacement, Verbatim #52045, 1206-162 can also be used.
• Yellow LED strips (flexible self adhesive strips with SMD LED's) rated for 12V dc.
• Bright red LED light oriented towards tremulant: LRW5SN VPA1A, 120 degrees, Vf=3.3V. Two such LED's in series with current limiting wirewound power resistor. (mapped on midi note 121)

Technical revisions and maintenance notes:

• 18.09.2009: Instrument signaled to us by Zimcke Van de Staey.
• 19.09.2009: purchase of the original Emile Kerkhoff instrument in Herselt. Brought to Ghent by Yvan Vander Sanden. Basic tuning checked to be 440 Hz. The case had to be taken apart in order to make the transport possible.
• 22-24.09.2009: Measurement of components, further dismantling of the original instrument, first sketches for a new design.
• 26.09.2009: original instrument further taken apart and analyzed. On the picture the instrument is shown in the state we received it in the workshop. The sound board has a series number: 54938. After removal of the keyboard assembly the box containing the 13 reeds for the subbass extension becomes visible. The problem will be to make all the mechanics such that noise is minimized. We decided to preserve the keyboard, since it seems to help reducing the required solenoid forces for they function as levers. Solenoids ordered from Farnell: Black Knight type 121-420-620-620.
• 27.09.2009: TIG welding of the support frame for the bottom plate of the windchest: 2 pieces 50x50x2 square tube, length 484mm welded on 50x3x1165mm, flat stainless steel. Wheel axis tubing: 25 x 2 x 500. Wheels: 400mm diameter. Ventola blower ordered from August Laukhuff. (order number 612380). This blower will be mounted vertically, under the windchest. The bottom plate of the windchest is to be mounted on this frame in a permanent way.
• 28.09.2009: Harmo building project shown and explained to Kristof Lauwers and Troy Rogers. Further design of the wheelbase.
• 29.09.2009: TIG welding work on the frontal square tubing connecting the wheel assembly to the windchest carrier.
• 30.09.2009: Further TIG welding work on the trolley. Some tuition given to Troy Rogers on welding technology, metal working and robot construction.
• 01.10.2009: drawing of circuit overview. Estimation of board real estate required.
• 02.10.2009: design session for the mechanics of the registers and expression mechanism.
• 03.10.2009: Further work on the trolley construction.
• 04.10.2009: design of wind-inlet and motor mounting. Varnish restored with polyvinyl alcohol.
• 05.10.2009: Drawing of the welding plan.
• 06.10.2009: Start construction of the solenoid holding structure. The structure is a piece of stainless steel plate, 2mm thick bend in an asymmetric U shape: 140mm x 60mm x 50mm, cut to a length of 1050mm. Drawing, marking, centering and drilling of the 73 holes, diameter 14.5mm, with the help of Troy Rogers. Delivery of a first set of 29 solenoids from Farnell.
• 09.10.2009: Drilling and centering works.
• 11-12.10.2009: More drilling work... all 14.5mm holes drilled.
• 13.10.2009: 10mm thick side-plates for the 'vorsetzer' cut out. Placement of the six note-control PC-boards decided: the will lean against the back of the solenoid assembly. The wires from the solenoids will get through the PC boards via large holes drilled in the backplate. This gives us space for some lights on the frontal side.
• 14.10.2009: Further work on the vorsetzer design.
• 15.10.2009: T-shaped back bounce bar designed. This can be either made of hardened brass or stainless steel 30x30. The flat side should have 6 to 10mm thick felt. Measurement of required force to pull the registers: 5 Newton (peak <=10 Newton) Thus August Laukhuff - Trakturmagnet, 24 V 0.5 A @ 100%DC - 10 Newton can be used for all 8 registers. The power supply at 24V therefore will have to be dimensioned for at least 4A at 24V continuous. A 100 Watt SMPS type can be used. The front and back swell require a force smaller than 3 Newton, when the needle return springs are removed. With the springs, the required force is 10 to 15 Newton. We will try softshift solenoids: Ledex Softshift type 5EP, number 193015-026. Cold DC resistance 10.3 Ohm. Nominal working voltage at 100% duty cycle: 14 V (force = 8 Newton), at 50% (force = 18 Newton) , 20 V, at 25% (force= 30Newton) , 28 V at 10%, 44 V (force= 50 Newton) . Price (no joke): 144 US $ a piece... Since we expect most users to have the swells opened most of the time, we should design for operation at 100% duty cycle.
• 17.10.2009: Construction of the power supply bars in red copper. Drilling of the 12 mm holes in the mounting flanges. Vorsetzer assembly welded together.
• 18.10.2009: Test assembly. Exact measurement of required solenoid travel on the different components to be automated. The hold voltage for the key-solenoids will definitely not have to be greater than 12V. If we would want to allow full clusters, this would entail a power supply capable of delivering some 45 A. (500 Watt).The velocity pulse voltage can be a relaxed 24 V and certainly not more than 48 V.
• 19.10.2009: In place check & verify design: Sideplates to carry the vorzetzer. Left en right side pushing solenoids with rubber feet.
• 20.10.2009: Wiring tables fixed for the pulse/hold boards. Bending of the limiting side arc profiles (50 x 3 stainless steel) with Troy Rogers.
• 22.10.2009: News from Laukhuff: the compressor, as ordered, will be delivered week 44, that is first week of November.
• 23.10.2009: Cutting and drilling of the four vertically mounted register solenoid holding plates.
• 24.10.2009: further work on the carrying structure for the vorsetzer and the register solenoids. The two solenoids on each side placed in a horizontal plane are mounted with M3 bolts. The holes in the chassis are threaded. The vertical ones are mounted with bolt and nut, M3. Mounting slots drilled and filed out.\
• 25.10.2009: Mounting slots bass side filed out. Solenoids ordered from Laukhuff: Trakturmagnet 24V, catalog number 300810. TIG welding work on the bass side vorsetzer holder.
• 26.10.2009: Welding work on the arc, treble side after cutting out the arc section in the thick vertical holding plate. Construction of a guiding wheel with a 16mm outer diameter ball bearing for the movement of the frontal shutters.
• 27.10.2009: Bass side finished similarly as the treble side: arc cut out and welded on the thick vertical plate. Removal of all needle springs on the registers and the shutters. Experiments with the soft shift solenoids (Size 5EP, Lucas Ledex, order number 193015-026) carried out. At 100% duty cycle operated on 14V dc these have a starting force of 8.8 Newton, at the end of the 10mm stroke traject the force goes up a bit, reaching 13.3 Newton. Power consumption under these conditions is about 21 Watt. Speed (unloaded) is ca. 45ms for the full traject. Wheel mounted on the key-holder plate. Pulling thread connected to the frontal shutter.
• 28.10.2009: Linear stepper motors ordered as an alternative for the soft shift solenoids: Nanotec L5609X2008-M6x0.5. This type has a thrust of 85 Newton, a resolution of 0.00125 mm and a feed of 20 mm/s. Current per winding is 2 A. ( http://www.nanotec.com ). The cost (including the spindle, with a M6 x 0.5 thread, which is to be ordered separately) is about 120 Euro a piece. We ordered stepper controllers for these motors (Type SMC42) and these cost 93 Euro a piece, bringing the price for the entire mechanism to about 426 Euro. Mounting plates with holes for either softshifts or these linear motors made and welded into the treble side chassis.
• 29.10.2009: Design of the mechanism for the back shutters to be mounted on the bass side chassis. Here the traject can be kept pure vertical without any need for a guiding wheel. The way it looks now, we can probably go without using sensors, on the sole condition that on startup, the shutter valves will always be in a fully closed position. They can be brought there by hand, by rotating the cylindrical part of the hollow bronze motor shaft. The midi controller range 0-127 should be remapped on the number of rotations required for the full traject. A counter should be kept in the software. Welding and mounting works on the bass side chassis for the linear stepping motor. The pictures show the welded and roughly brushed assembly for the bass side chassis with no parts mounted.
• 30.10.2009: Nanotec stepper motor controller delivered. The fan will have to be removed since it is noisy and in this application not even required, taking into account the duty cycle applicable to the shutter valves. The controllers will be mounted right on the curved side chassis in order to reduce possible EMC from the otherwise long wire bundles to the motors. The motors have 8 wires and the windings are connected in series for full bipolar operation. Mounting holes drilled in the side chassis. The controllers are mounted with two M3 x 10 bolts.
• 31.10.2009: Construction of the register lifter for the subbass box. The picture shows the construction, but the felt washers are missing. The solenoid is a small Laukhuff pallet lifter rated for 24V. The force at the nominal voltage is too small to securely lift up the register valve, but when driven with 30V it opens smoothly. The hold voltage can be kept at 24V. Another solution would be to add a second solenoid -operating in parallel- at the other side of the valve, thus doubling the force. That's the way we decided to go, for it saved us complications with too many different power supply voltages. Experiments did reveal that it would be possible to use the registers in a gradual way, provided they are always switched off with the full voltage and then lowering this voltage with PWM. The down traject is very well controllable, not the upwards traject.
• 01.11.2009: Construction of the tremulant mechanism using a softshift solenoid and a conical valve. The seating for the valve was milled out in hard wood, such that it can be glued right on the 16mm hole for the original tremulant, in the soundboard. Start mounting of the key pressing solenoids on the Vorsetzer chassis. The nuts are fixed with Loctite 243 (blue).
• 02.11.2009: Assembly of the spindle motors and controllers: The fans have to be removed. The first picture shows the horizontal spindle motor driving the frontal swell, the second the vertical spindle motor driving the backside swell. Start soldering work on the note driver boards. The bass side board is only fully populated for the highest 8 outputs. Series diodes here are BYV28 - 200V. Mosfets: all IRL640, P-channel mosfets: BSP254A. It is harmless to mount all P-channel mosfets, regardless the way the board is used. Troy Rogers is helping us out with the soldering works on these boards. Boards 2-5 are identical, boards 1 and 6 have a slightly different component selection due to the use of outputs for the register solenoids. Just for the sake of comparative measurement and evaluation, we populated the high note board (board 6) with BS250 P-channel mosfets and did all soldering lead-free.
• 03.11.2009: Continuation of soldering works. We run out of diodes... fast order to Farnell. Three board are already fully populated and finished. Three more to go... The picture shows board 6, with special component selection in order that the same board can be used for switching 4 registers, one light and nine notes. Since the register solenoids are switched to the negative 24V supply, the protection diodes (BYV32) have their central pin connected to ground. In order to gain some more experience in future technologies (Sn/Pb solder may disappear...) , we soldered this board leadless. It looks dull...
• 04.11.2009: Work on the red copper power supply bars connecting the boards on the backside of the vorsetzer. The missing tracker solenoids from Laukhuff have flown in and thus the register automation can be finished as well. Orders placed for two Siemens Sitop 24V/10A supplies as well as for a 20A 12V supply, made in Norway. Lets pray they come without fans and can cope with the surges caused by the switching solenoids... With these components in the power supply, polyphony will be limited to 32 notes simultaneous. We decided not to provide full 73 note polyphony (requiring a 45A power supply for the +12V) because the compressor would never be capable to provide enough wind to make all those reeds sound properly.
• 05.11.2009: delivery of the compressor as ordered, only... Laukhuff did mount the regulation valve on the suction side, whereas we wanted it on the wind inlet side... This way it does not fit on the trolley we have already welded together. Finalisation of the board soldering works after delivery of the missing diodes by Farnell. The power supplies came flowing in and they are fan-less!
• 06.11.2009: Preliminary mounting and assembly of the entire robot with clamps. Verification of the construction drawings. Start construction of the windchest inlet for the compressor. Opening of the original windchest and pallet/reed check. We took the decision to leave the slider wind control on the suction side.
• 07.11.2009: Welding works on the trolley. Design of an automation for the windvalve; a motor driven dented belt seems appropriate here. The windchest slider can be seen on the picture. The motor, the rotor is clearly visible, mounted on its supporting bars: We may even have enough space for the power supply (12V/20A) under the bottomplate of the motor. Closing blocks made from teakwood for the closing sides of the windchest inlet. These are glued on with silicone compound. After curing, we will close the windchest with a plate of 2mm thick stainless steel, 960mm x 24mm.
• 08.11.2009: Positioning of the power supply components and the Siemens motor controller. Mounting brackets made for motor controller, two Siemens power supplies (rail mount) and the 12V power supply. Power wiring can start now. The 5V power supply still has to be given a place. Windchest closed with 2mm stainless steel plate. Recycled antique power switch mounted under the windchest. In this picture we see the 12V power supply mounted under the motor: This picture shows the two Siemens 24V power supplies: This is a view from underneath, showing the now completely closed windchest inlet: This picture shows the positioning of the motor controller such that it is easy accessible for the programming of the motor parameters:
• 09.11.2009: Placement of 5V power supply. Design of the mounting of the power inlet, the midi hub board and the extra required board for the ghost and the steppers. Wiring of the all mains connections as well as the power switch. The motor is now star-connected for operation on 3-phase 230V.
• 10.11.2009: Mounting of the mains power inlet (male CEE blue). Cutting out of a polycarbonate carrier plate for the midi input board. Check of motor operation. Should we provide build in metering/monitoring of the critical voltages? Start of the design and construction of the third standing leg.
• 11.11.2009: Construction of the standing leg. This leg is demountable and fixed to the chassis with two 12mm bolts. Programming of the motor controller and test. The motor to windslide connection is still a bit leaky. Fixing bolts mounted for the windchest closing plate (M4 x 35). White LED spotlight mounted on the underside, pointing to the floor.
• 12.11.2009: Construction of the steering handle and the wire feedthroughs to the upper side of the robot. Design of a metering panel. Design of the poltergeist... Construction of the power feeds in red copper strips mounted under the windchest. The screw heads (brass screws) are soldered to the copper strips.
• 13.11.2009: The spindles with the M6x0.5 thread came in. Wiring of the spindle steppers. Mounting of the ghost solenoids on the back of the windchest. Beaters are made of wood. Cables bundled on the underside.
• 14.11.2009: Wiring of the midi-input board. We may run out of Weidmueller connectors today... Mounting of an experimental drive for the windvalve on the motor. It's using a recycled Burroughs Sonceboz motor (type 1251 0228) rated 0.6A /phase and 9.5 Ohm/phase and a Nanotec motor controller. Furthermore it drives a dented belt (cut) length 78cm that connects at both ends to the slide with two M3 bolts. Cutting out of the front panel for the analog meters for power supply monitoring. Welding of the stand off's.
• 15.11.2009: Finish of the analog power supply voltage metering panel. Mounting of the Nanotec stepping motor controller for the Burroughs stepper. Tests of this motor in combination with the controller: the optimum clock frequency for this motor seems to fall in the range 186 Hz to 240 Hz. At 186 Hz it draws (both phases together) 1.2 A from our 24 V bench supply. At 240 Hz, the current sinks to 840 mA. Higher clocks reduce the torque such that it becomes unusable in this application. It it essential to set the enable pin to high whenever the motor is not running. The holding current at halt is way too high, and we do not need any holding torque anyway. For the potentiometer sensor, we need a dented wheel with a diameter of minimum 30 mm, since we should have less than 300 degrees of rotation for a movement traject of 65 mm. Start writing out of the PIC programming specifications.
• 16.11.2009: Up to MEA for ordering the missing mechanical parts... Check of component placement and lay out of midi hub board recycled from the previous version of Autosax. This board can take care of the compressor motor as well as the two linear steppers for the swells.
• 17.11.2009: Component selection and placement for the small pulse board. Since this board does not have programming pins, we make sure not to use those pins on the pic, such that we preserve the goodies of in circuit debugging. Wiring windslide motor controller to mini-PIC board. Finishing of the horizontal movement of the windslide, using an extra dented guiding wheel in nylon. Belt cut to size and fixed to the slide with M3 bolts and an insulating washer.
• 18.11.2009: M&M darkness concert: no HarmO works. To to: change the Burroughs motor bolts to M3.5 x40 types. (Now: M3 x 50)
• 19.11.2009: further work on PIC-specs. Further work on wiring as well as mounting of the pulse/hold boards on the vorsetzer. Copper power supply rails fitted to the six boards with assistance from Troy Rogers. Saturday promises to become PIC programming day with Johannes Taelman...
• 20.11.2009: Weidmueller connectors delivered. Further wiring... First test of the reeds and registers with the new wind supply. In the high treble, there are quite many problems with the reeds. The design of the tremulant using a conical valve was a big mistake as it came out. The tremulant in a reed organ does not work at all in the same way as in pipeorgans, but simply works by waving a reflective surface in front of the sound source... We are up for a new design now.
• 21.11.2009: Reed testing. First programming session on the PIC's with Johannes Taelman. All note/velo boards programmed (boards 1 to 6) . Midi-hub board PIC programmed for compressor motor functions. To be done: stepper motors for swells as well as the PIC processor on the 16-output board. Mounting of the five frontal yellow 1W high power LED reflectors.
• 22.11.2009: Wiring of the 5 frontal lights. Experiments with different doppler-based tremulant drives. Wiring of the solenoids finished by Troy Rogers. Found a nice DC motor from an old portable tape recorder very suitable for driving the doppler-tremulant. The advantage of using a DC motor here being silent operation and ease of control: it just requires a single PWM output from a PIC. The motor is rated for 6V, but can be driven at much higher voltages. As an alternative, a Crouzet stepper could be used with a steering circuit as: The 50k pot could be exchanged for an optor and thus the circuit would become compatible with the PWM PIC output drive.
• 24.11.2009: Design and construction of a connector for the high side spindle motor (Bulgin 8-way connector), such that the side parts can be taken of without having to loosen screws. Two connector contacts are as yet uncommisioned. Final wiring of the high side register solenoids.
• 25.11.2009: Design of a similar connector for the low side. The support for the 12-pole Bulgin connectors selected here, welded on the structure. The input signal for an optional sensor is connected in the male connector (white wire). Wiring of the bass-side. Wire bundling.
• 26.11.2009: further wiring: subbassregisterbox. Corrections of the attack points of the solenoids on the keys. Fixation of the rubber feet on the anchors with cyanoacrylate glue (Loctite 431). GMT test code written by Kristof Lauwers tested on the instrument. HarmO played already its first complete scale... Some reeds need fixing however. There is a noticeable difference in the required velocities for the front row solenoids as compared to those on the back row. This must be fixed in the sysex lookups.
• 27.11.2009: Wiring of the two super bright red led's for the tremulant mechanism. This will work as a rotating flashlight. Construction of tracker wires for the register solenoids using guitar strings. This is as yet not an optimum solution and the registers may need a small spring or counter weight to make sure they always return to a fully closed position. Construction of the wings and the motor mount for the tremulant mechanism. The wings are made from Hasberg measurement steel, 50mm wide and 0.5mm thick.
• 28.11.2009: Search for a solution for the 2-pole connector required for demounting the subbasbox register solenoid assembly. Rewiring of the ground connections for the high side register solenoids. Rotator for the tremulant mounting with a PTFE spacer. Fixed on 2 mm motor shaft with cyanoacrylate. The motor mount was made from black tropical hardwood, glued to the stainless steel baseplate with silicon glue.
• 29.11.2009: Wiring and mounting of the tremulant mechanism. Test controller 82. Something must go wrong, because our +12V supply lead went into flames... Shorted mosfet?
• 30.11.2009: Hardware debug of midihub board: no failure detected. Board mounted again. Functions o.k. but speed will have to be limited. Also there is a bug in the PIC software, since the motor speed control (midi controller 82) works the other way round. Mounting of the yellow SMD-LED strip under the vorsetzer assembly. This is mapped on midi note 127, tested o.k. Start construction of the damper bar from hard brass. The mounting is not without problems because the M10 bolts holding the vorsetzer are in the way of the four M6 bolts required for adjusting the damper bar.
• 01.12.2009: Construction of precision mounting blocks in hardwood to facilitate allignment after disassembly of the vorsetzer. Further study of the damper bar construction problem. Felt strip cut out (12mm thick, 30mm wide) and glued to the brass damper holder with polyurethane glue. Adjustment must be done with the 4 M6 nuts.
• 02.12.2009: M10 kogelkoppen ingekocht voor montage en vastzetten van de vorsetzer. Bouten vervangen door M10 x 30 exemplaren. Oud tremulant windgat gedicht met een messing ornamentje, vastgezet met siliconen rubber. Aanpassing van het GMT test en stuurprogramma door Kristof Lauwers.
• 03.12.2009: Considering some frontal ornamental parts to break the strong horizontalism of the automate. Construction of the cable guide on the backside from stainless steel L profile 20x20x3. This part is removable and fixed to the side bows with two M6x16 inbus bolts. Finalisation of the single standing leg: welding of a 30x10x80 standing plate on the 25mm tube, glueing of a 7mm thick hard rubber pad underneeth. Pic-spec file updated for Johannes Taelman.
• 04.12.2009: Wooden wings sawn out for the front: derived from the original knee-swell levers. These are functional in that they prevent damage on the keys in transportation, as the keyboard sticks out slightly from the base. Decided to add a stainless steel arc to connect both bows on the side. In common consent with Troy Rogers, Moniek Darge, Kristof Lauwers and more collaborators and users here at Logos. A spherical mirror will also be added to the motor underneeth.
• 05.12.2009: Update of the test software in GMT. Construction of the arc.
• 06.12.2009: Further tests under software control. HarmO played the complete Goldberg Variations today... Return springs added to the registers. Great discovery: it is possible to remove the reeds without dismantling the entire automate. However, we need to design a special tool, a reed-puller, first.
• 07.12.2009: HarmO demonstration for my collaborators at Logos.
• 08.12.2009: Whilst I'm trying to trace a reed extractor for HarmO, Troy Rogers started exploring the almost newborn robot.
• 09.12.2009: <harmO> weighted: 115kg.
• 10.12.2009: Construction of a tool to extract the reeds for tuning and maintenance.
• 11.12.2009: Cleaning out of non-speaking reeds. Sysex lookup tables programmed by Kristof Lauwers. To use this velocity scaling, send a program change command with value 122.
• 12.12.2009: Waiting for Johannes for further work on the PIC firmware... New doppler-sonar gestrobo study written, including <HarmO>: 'Far stars fade with spectral shifts'. Will be premiered on december 17th by Dominica Eyckmans and myself.
• 15.12.2009: PIC works with Johannes: bugs in boards 1 and 6 repaired. Inverted PWM on tremulant motor corrected. First version firmware for the pulse board (#8): the lights are all implemented now.
• 16.12.2009: Redump sysex lookups for boards 1 and 6. Adjustment of the register springs and solenoid trajects by Troy Rogers. Yvan Vander Sanden and Troy Rogers are writing a piece for <harmO>, to be premiered tomorrow! Rehearsal of the interactive piece with Dominica Eyckmans. Blue LED spotlite added and mapped on midi note 119.
• 17.12.2009: First public appearance of <harmO>.
• 18.12.2009: Mounting of an AC solid state relay for the white LED spotlite underneath.
• 19.12.2009: HarmO played a little concert for four bologneser dogs...
• 20.12.2009: Programming connector mounted on the 16 pulse output board to facilitate in-circuit programming and debugging of the windslide motor control firmware.
• 21.12.2009: mounting of an AC solid state relay for the white LED spotlite, mapped on midi note 120. Circuit drawings updated as well as the picspecs for programming. Solid stated relay: Siemens V23100-S0032-B302 +3 to +5V DC switching voltage, 2A/240V switching capacity.
• 22.12.2009: Light test reveals that the white LED spot does not fully turn off, even though the relay input is off. The leakage current through the solid state relay is appartently large enough to make the LED assembly light up gently.
• 23.12.2009: Professional reed organ tuner found in Woerden (Netherlands): Arie Schuller. Planning to drive HarmO there for tuning.
• 28.12.2009: Appointment made with the reed organ tuner in the first week of january. Meeting with Johannes Taelman to discuss the implementation of the two swell stepping motors.
• 02.01.2010: Work session on the firmware for the swell motors and the windvalve with Johannes Taelman. The swells should now work, although not very fast...
• 05.01.2010: Swell test code added to GMT.
• 06.01.2010: Inventarisation of the fine tuning work to be done on the reeds.
• 07.01.2010: <HarmO> is off to Woerden, Netherlands, with Yvan Vander Sanden and Troy Rogers for tuning. Despite the snow... It came back around 21h40. A few reeds in the highest octave of the 4" register seem to be untunable and will need replacement. The problem will be where to find replacement reeds... Purchase of a special tongue puller tool:
• 08.01.2010: Motor controller, Siemens G110, reprogrammed for higher wind pressure range. The settings for the volume controller have to be adapted in all already existing code and file material accordingly. HarmO now has a very high dynamic range, but caution is required with high wind pressures as leaks can occur. The default settings in GMT have been updated.
• 11.01.2010: Failure in the back swell solved: a 10x enlarging lens was left under the flap by the tuner...
• 13.01.2010: Motor controller needs better programming: now it gives error F910 at sudden changes of wind pressure.
• 17.01.2010: Apparently there must be a firmware bug in the implementation of controller 66 (motor on/off). To be checked with Johannes.
• 20.01.2010: considering the design of a sensor mechanism for the swells. Pepperl+Fuchs sensors appear to be a good choice for sensing the closed position of the swells.
• 23.01.2010: PIC firmware programming session for the windvalve stepper (ctrl.1) with Johannes Taelman. Now this works pretty well. Maximum speed is about 4 times a second for the entire movement trajectory. The ghost beaters still have to be implemented.
• 24.01.2010: Thorough test and debug session. We encountered still inconsistencies in the workings of ctrl.66.
• 25.01.2010: A note on tuning reeds in reed organs, by Troy Rogers,
• 27.01.2010: Replacement reeds ordered for the untunable reeds in de 4' register.
• 31.01.2010: Extensive tests of the windslide. Slipping can occur, so we may need to add some kind of position sensor.
• 12.02.2010: <HarmO> is off to Hasselt for the Boink! festival there.
• 15.02.2010: Crash reported in Yvan piece in Hasselt. On return, Harmo was o.k.. What's the trouble, whats the cause?
• 17.02.2010: Minor repair required on the subbas valves: if struck too hard, they often do not fall back in place.
• 21.02.2010: Waiting in vain for Johannes to fix some bugs and get the poltergeist working...
• 27.02.2010: Debug session with Johannes on the new midi-parsing code section in the midihub and pulse board PIC's. The start-up problem seems to be reproducible and may have to do with memory initialisation of the PIC. It has been demonstrated that it is not the midi flow itself that causes the erratic behaviour. The PIC's seem to reset automatically under certain as yet undetermined conditions. This is problematic since it also means that the PIC then forgets the position of the swell controllers.
• 13-18.03.2010: Work on interactive code for the demo at the Jazz & Sounds festival. Loss of controller 66 signal is still a recurrent problem.
• 19.03.2010: The dented wheel got loose from the motor axle and needed a repair. After this, controller 1 for the windslide will be functional again.
• 22.03.2010: HarmO demonstrated at Bijloke, Jazz & Soundsfestival
• 26.03.2010: Work on the interactive code for tomorrows concert with clarinetist Daniel Pastene.
• 22.05.2010: Revision of the firmware for the midihub board PIC controller. Hopefully we solved the bug in the quite unreliable startup, most noticeble with the implementation of ctrl 66. Though this board is still programmed in C, we believe assembly (or... Basic) to be much more reliable...
• 01.07.2010: Harmo seems to work reliably now, but the Poltergeist is still not implemented in the PIC code.
• 09-10.10.2010: Harmo plays on the opening of the STAM museum on the Bijloke campus: 12700 visitors...
• 11.10.2010: Basic proves to be a much tighter programming language than C for our PIC controllers. The Proton+ compiler produces a lot tighter and more efficient code than Microchip's own C compiler.
• 10.11.2010: Reconsidering the firmware coding for the windslide motor.
• 30.11.2010: Redesign of windslide motor circuitry, using a separate PIC controller and at least one position sensor. This PIC can also take over the control for the ghost beaters
• 02.12.2010: Small ferromagnetic hooks mounted on the edges of the windvalve slider such that we have something to sense for our NAMUR proximity sensors. Pepperl+Fuchs NAMUR sensors mounted on two small blocks of hardwood. These will be glued on the side of the windchest such that they can sense the endpositions of the slide
  
• 23.11.2012: White GU10 socket bulb replaced with Verbatim 6.5W LED.
  23.02.2015: New circuit and PCB designed and drawn for the radial compressor motor controller.
  And here is the new circuit drawing:
• 24.02.2015: Etching , drilling and soldering of the new motor control circuit board. This is the connection diagram for the Sinamics motor controller:
• 25.02.2015: Writing and testing of the motor control firmware, with build-in intelligence. Here is the source code. (Proton compiler).
• 26.02.2015: Start mounting of the new motor control board on the chassis.
• 27.02.2015: Test session with the new motor control board. Close inspection of the swells revealed broken hinges. In fact, a piece of glued-on textile ribbon was used as hinge material here. We will need to replace this with something more durable.
• 28.02.2015: Bug removed in the hardware of the motor controller PIC: the opamp should not be inverting! Corrected on the board and in the circuit drawing. Further tests under GMT.
• 13.09.2018: <HarmO> found no longer functioning. Apparently something goes wrong with the port assignments.
• 16.09.2018: Harmo replaces Krum now. Everyhing works fine, except the 'intelligent motor control'... Setting ctrl.67 to 1 and steering the wind with commands solves the problem for now. We have to continue the work on the motor microcontroller firmware.
• 16-18.04.2020: The corona madness gives us some time to have a look again at the motor control firmware for <harmO>.
• 27.11.2020: Rehearsing with Emilie De Vlam for a corona-lockdown streaming on december 3th.
• 04.04.2021: Motor control PIC reprogrammed. There is still ample space for refinements.
• 05.04.2021: Apparently we never got to improve the firmware on the hub board... It's about time to get this done... We might consider to change the swells completely, by using DC motors and sensors. The steppers we had are too noisy in any case.
• 27.11.2022: Revision of the motor control firmware. Now using 10-bit PWM at 39kHz. Efficiency greatly improved.

To be done:

• coding for the ghost beaters mapped on notes 0 and 1
• PWM implementation for the yellow led's such that they can be dimmed.
• replacement of the non-speaking reeds in the highest octave of the 4' register.
• re-write the PIC firmware for the windslide (Controller #1) and throw in end position sensors.
• wiring clean-up.

Literature and bibliography:

• Analog Devices: AD820 Datasheet
  Sears, Roebuck and Co., "The reed organ", Chicago, 1910
• Barbara Owen, "Reed organ", in: 'The new Grove dictionary of musical instruments', ed. Stanley Sadie, Macmillan Press Ltd, NY 1984
• Robert F. Gellerman, "Gellerman's International Reed Organ Atlas", ed. Vestal Press. (ISBN 1-879511-34-7)
• Bowers, David Q., "Encyclopedia of Automatic Musical Instruments", ed. Vestal Press, New York 1972 (ISBN 0-911572-08-2)
• Raes, Godfried-Willem, "Expression control in automated instruments", 2010/2022
• Raes, Godfried-Willem, "Logos @ 50, het kloppend hart van de avant-gardemuziek in Vlaanderen" (ed. Stichting Kunstboek, Oostkamp, 2018)
• http://www.perfectthird.com/harmonium_repair.htm
• Rogers, Troy, "A note on tuning reeds in reed organs" (2010)
• Siemens Gmbh, 'Sinamics Motor Controller Manual' (2005)
• Siemens Gmbh, 'Sinamics Motor Controller G110 parameter list. (2005)

Robody picture with <HarmO>

last update: 2022-11-27 by Godfried-Willem Raes