<Bomi>


an automated organ gedeckt register

Godfried-Willem RAES

2009-2010

[Nederlandstalige versie]

Robot: 'Bomi'

The design of this musical robot started with an offer found on the August Laukhuff website for a wooden 4-feet register perfectly suitable to complement our <Bourdonola> robot, or to yield to an easy transportable organ module. The sound was designed such as to be soft and gentle, but still pretty rich in overtones and with a clear slightly spitting attack.

In the <Bomi> robot we designed around this register, the notes are switched inside the windchest with conical electrical pallets, solenoid driven. Doing so, we obtained velocity sensitivity for each individual note as well as individual keypressure modulation. Global wind pressure control is possible over a wide range, although as can be expected from flue pipes, tuning cannot be guaranteed under extreme deviation from the normal pressure circumstances. The global pressure control is mapped on midi controller 7, as it is related to the sound volume. Maximum wind pressure is 65 mm watercolumn (= 6.5 mbar) and generated by a small 70 Watt Laukhuff Ventola-type organ blower driven by a programmable 3-phase motor controller from Siemens. Air production is 1 cubic meter a minute. Normal working pressure should be 45 mm watercolumn (4.5 mbar). Tuning is pretty much stable in the range 40 to 50 mm H20. A manometer as well as a thermometer are mounted on the windchest. A tremulant, using a softshift solenoid valve on the wind inlet in the windchest, is also part of the design. Its operation can be seen as we made the windchest transparent. The softshift valve used here to steer a conical valve can be controlled with midi controller 1, however, its function is inverted such that for controller value zero, the valve will be fully opened and for value 127 fully closed. The all notes off command (controller 123) always resets this valve to the fully opened state. The valve can very well be used for fast responding dynamic control as well as for inflections.

The entire circuitry for this robot makes use of three fast PIC controllers: Microchip PIC18F4625 - I/SP types. For each group of 14 notes, a controller takes care of the midi input parsing and the note on/offs, mosfets and conical valve solenoids. There is precise control over the note attack (the velocity byte accompanying each note on command controlling the response speed of the valves) as well as over windflow modulation during the sounding of a note. This is implemented with polyphonic midi note aftertouch commands and, on the processor level, by applying slow PWM to the hold voltages over the solenoids. This is the principle: It is important to the user to know that the velocity byte in the midi note-on command does not control sound volume, but only the way the pipes speak. It is strictly an attack control. For detailed circuitry and board population, we refer to the webpage of our <harmO> robot, since it uses the same boards. The PIC firmware however is very different, since here we implemented the PWM steering required for the key pressure control. A fourth PIC microcontroller (a 18F2525 type) takes care of the steering of the windvalve/tremulant as well as of the motor commands and the PWM for the 3-phase motor controller.

Description of the organ register:

Name: Gedaeckt, 4' - 37 stopped wooden pipes. (3 octaves)

Light colored oak wood is used for the pipes. The wood is left in its natural and untreated state. The pipefeet have individual regulating screws. The pipes are tightly fitted to the windchest using easily replaceable Teflon tape (PTFE)., the same type as used in general plumbing. Since the instrument is designed for transportation, the pipes are inserted deeper into the upperplate of the windchest than usual in traditional organ building.

The scale used for the register is (scales in mm):

    internal external pipe length pipe length from flue length of foot

diameters

(20mm traject)

 hole size conical valve
note 55 g 0 37.0 x 49.0 50.0 x 63.0 460 mm 400 mm 60 14.5 - 17 10 24
note 56 g#0 35.5 x 47.0 49.0 x 61.0 435 mm 378 mm 60 14.5 - 17 10 24
note 57 a 0 33.5 x 45.0 47.0 x 59.0 414 mm 355 mm 60 14.5 - 17 10 24
note 58 a#0 33.0 x 43.5 46.0 x 58.0 392 mm 336 mm 60 14.5 - 17 10 24
note 59 b 0 31.0 x 42.0 45.0 x 56.0 370 mm 313 mm 60 14.5 - 17 10 24
note 60 c 1 29.0 x 41.0 43.0 x 54.0 340 mm 280 mm 60 14.5 - 17 9 24
note 61 c#1 28.5 x 38.7 42.0 x 50.5 324 mm 267 mm 60 14.5 - 17 9 24
note 62 d 1 27.0 x 37.5 40.0 x 50.0 305 mm 250 mm 60 14.5 - 17 9 24
note 63 d#1 26.5 x 36.0 38.5 x 48.5 290 mm 237 mm 50 13 - 15 8 /8.5 18
note 64 e 1 25.0 x 35.0 37.0 x 47.5 274 mm 220 mm 50 13 - 15 8.5 18
note 65 f 1 23.5 x 32.5 34.5 x 45.0 260 mm 210 mm 50 13 - 15 8.5 18
note 66 f#1 23.5 x 32.0 34.5 x 43.5 250 mm 195 mm 50 13 - 15 8.5 18
note 67 g 1 23.0 x 30.0 33.0 x 42.0 238 mm 185 mm 50 13 - 15 8.5 18
note 68 g#1 21.5 x 30.0 32.0 x 40.5 227 mm 175 mm 50 13 - 15 8.5 18
note 69 a 1 21.0 x 29.0 31.0 x 40.0 220 mm 170 mm 50 13 - 15 8.5 18
note 70 a#1 20.0 x 27.5 30.0 x 37.5 207 mm 159 mm 50 13 - 15 8.5 18
note 71 b 1 19.5 x 27.5 29.0 x 36.5 199 mm 151 mm 50 13 - 15 8.5 18
note 72 c 2 18.7 x 25.5 28.5 x 35.4 190 mm 143 mm 50 13 - 15 8 / 8.5 18
note 73 c#2 18.0 x 24.5 28.0 x 34.5 180 mm 133 mm 40 11 - 14 7 / 6.5 16
note 74 d 2 17.0 x 24.0 27.0 x 34.5 175 mm 128 mm 40 11 - 14 6.5 16
note 75 d#2 16.5 x 22.9 25.0 x 32.0 169 mm 122 mm 40 11 - 14 6.5 16
note 76 e 2 15.5 x 22.0 24.5 x 31.0 162 mm 117 mm 40 11 - 14 6.5 16
note 77 f 2 15.0 x 21.0 24.0 x 30.0 155 mm 109 mm 40 11 - 14 6.5 16
note 78 f#2 14.5 x 21.0 23.5 x 29.5 150 mm 105 mm 40 11 - 14 6.5 16
note 79 g 2 14.4 x 19.5 23.0 x 29.0 145 mm 100 mm 40 11 - 14 6.5 16
note 80 g#2 13.7 x 10.2 22.0 x 28.2 138 mm 94 mm 40 11 - 14 6.5 16
note 81 a 2 13.4 x 18.5 21.0 x 26.3 134 mm 90 mm 40 11 - 14 6.8 / 7 buisje 16 - changed to flat
note 82 a#2 12.5 x 18.0 20.0 x 26.0 128 mm 85 mm 40 11 - 14 6.8 / 7 buisje 16 - changed to flat
note 83 b 2 12.2 x 17.3 20.0 x 25.0 122 mm 80 mm 40 9 - 10.5 5 / 5 buisje 12 - changed to flat
note 84 c 3 11.6 x 16.0 19.8 x 24.0 120 mm 77 mm 40 9 - 10.5 5 / 5 buisje 12 - changed to flat
note 85 c#3 11.6 x 16.0 19.0 x 23.6 114 mm 72 mm 40 9 - 10.5 5 / 5 buisje 12 - changed to flat
note 86 d 3 10.9 x 15.8 19.0 x 23.5 109 mm 69 mm 40 9 - 10.5 5 12
note 87 d#3 10.1 x 14.7 17.0 x 21.5 104 mm 64 mm 40 9 - 10.5 5 12
note 88 e 3 9.8 x 14.0 16.5 x 21.0 102 mm 61 mm 40 9 - 10.5 5 12
note 89 f 3 9.0 x 14.0 15.5 x 20.5 98 mm 57 mm 40 9 - 10.5 5 12
note 90 f#3 9.0 x 13.0 15.5 x 19.5 95 mm 55 mm 40 9 - 10.5 5 12
note 91 g 4 9.0 x 12.5 15.5 x 19.3 91 mm 50 mm 40 9 - 10.5 5 12
                   

Size of the windchest upperplate in light oak-wood: 760mm x 240mm x 45mm. The pipes are arranged in two rows, the first row holds the pipes 69 to 91 and the back row the notes 55 to 68.

Approximate weight of the complete set of pipes: 20kg

Sizing of the wooden pipe-feet and pipes in two groups and/or rows on the windchest:

40 40 40 45 45 50 50 50 55 55 55 60 60 60
35 35 35 34 34 34 33 33 33 32 32 32 31 31 31 30 30 30 30 30 30 30 30

All pipes are switched by solenoid driven pallet valves with conical pads 25mm to 12mm in diameter. In order to make it possible to adjust the valves in the windchest without having to remove all the pipes, we constructed the pipeholder above the windchest such that it can be lifted up mechanically. Moreover, even without lifting the pipeholder, the mechanical parts can be accessed through the polycarbonate windows in the front and the back of the windchest. The electric connection between valves and steering electronics makes use of a series of Weidmueller connectors leaving the pipeholder through a vertical hole and a windtight cable gland. A manometer can be mounted on the windchest to allow for easy and precise adjustment of wind pressure in function of tuning operations. A thermometer is mounted permanently inside the windchest.

Preliminary view on the pipework assembled on the windchest during construction:

Circuit Overview:

Mapping

Midi implementation:

The midi channel for <Bomi> is 3 (0-15) or 4 (1-16).

Midi note range: 55 - 91. (c-g'') , velocity implemented (steers the speed wherewith the valves do open en hence the note attack). Individual note aftertouch (polyphonic) under development.

Note Off commands are required.

Controller 66 is used to switch the motor on or off.

Controller 1 is used for the windvalve: at value 0 it is fully opened, at 127 it is fully closed. Thus by default and after reset the valve will always be opened.
The tremulant is implemented as a modulation around the position of the windvalve as set by controller 1. Default value for controller 1 when using the tremulant: 80. With high modulation depth (controller #12) it should be smaller.

Controller 11 controls the speed of the tremulant. Normal values are between 100 and 110. The tremulant speed is the midi value divided by 10.

Modulation depth can be controlled with controller #12. Default value 60. This is the excursion the valve will make around the central position as set by controller 1. More gentle effects are obtained by setting this controller to 38 (with CC11 to 100 and C1 to 90)


Note that tremulant speed, depth and windvalve position interfere with each other and not every combination of values will work well.

Controller 7 is used for the wind pressure (motor speed). The normal setting should be 72. Default startup value in the PIC firmware is 0. It cannot be used for fast wind pressure modulation but is perfectly suitable for slow crescendo and decrescendo. Note however that the pitch as well as the intonation may be affected when Bomi is operated on nonstandard wind-pressures.

<Bomi> responds to the midi all-notes-off command. This command also switches off the lights and the wind valve, but not the motor. To switch off the motor controller 66 should be used.

Technical specifications:

Design and construction: dr.Godfried-Willem Raes (2009-2010)

Collaborators on the construction of this robot:

Music composed for <Bomi>:

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Nederlands:

Robot: <Bomi>

Voor de bouw van deze automaat maakten we gebruik van een eerder toevallige aanbieding op de website van August Laukhuff, voor een volledig in hout gebouwd 4-voet orgelregister met labiaalpijpen. Dit loopt vanaf midi noot 60 tot en met 91. De pijpen voor de noten 55-59 werden speciaal bijgebouwd. De windlade is, afgezien van het bovenblad waarop de pijpen rusten en waarvoor tropisch hardhout werd gebruikt, geheel vervaardigd uit gelast inox en polykarbonaat, waardoor een transparante windlade kon worden gerealiseerd. Geheel naar analogie trouwens met de windladen zoals we die eerder al ontwierpen voor <Qt>, <Trump> en <Krum>. De elektromagnetische ventielen waarmee de luchttoevoer naar de pijpen wordt geschakeld zijn ook hier binnenin deze windlade geplaatst. In tegenstelling tot eerdere ontwerpen, gebruikten we hier uitsluitend konische ventielen. Hierdoor wordt het mogelijk ook aftertouch na het aanzetten van een noot te implementeren. Hiertoe wordt de houd-spanning voor de elektromagneten in pulsbreedte gemoduleerd. Het elektronisch principeschema moge dit verduidelijken: Voor de windvoorziening maakten we gebruik van een kleine Ventola orgelblazer van de firma Laukhuff, met een regelbare winddruk van maximaal 80mm waterkolom, of 8mBar = 785 Pa, in eenheden uit de fysika. De aansturing van de 80 Watt motor gebeurt met een motorcontroller. Zoals voorspelbaar en normaal bij orgelpijpen, is ook hier de stemming enigszins afhankelijk van de winddruk. Alleen bij een motor AC frekwentie van 50Hz is de stemming korrekt. Winddruk 70mm H2O. Om een eenvoudige afregeling, stemming en intonering mogelijk te maken, monteerden we een precieze manometer aan de buitenkant van de windlade. Het maximale debiet van de kompressor is 1 kubieke meter, wat dus brede klusters ruimschoots mogelijk maakt.

De pijpen werden op de windlade gemonteerd in twee rijen overeenkomstig de twee verschillende maten van de pijpvoeten. De elektrische verbinding tussen de windlade en de elektronische besturing erbuiten gebeurt via een luchtdicht afgesloten kabelbundel uitmondend op Weidmueller konnektors. De besturing van <Bomi> komt voor rekening van niet minder dan 4 PIC mikrokontrollers: drie voor elke groep van 14 pijpen en een voor de besturing van de motor, het tremulant ventiel en de lichten. Alle elektronische besturingen, inklusief de voedingen, vonden een plaatsje onder de windlade.

Aangezien het gehele pijpwerk uit hout is vervaardigd, is deze robot niet geschikt voor openluchtkoncerten. Ze zijn niet in het minst vocht- of regenbestendig. Bovendien is ook zijn eerder zachte toon, niet voldoende krachtig voor straatgebruik. Als lid van het M&M robotorkest vormt hij evenwel een grote verrijking van het orkestraal koloriet.

Tessituur:

Audio-file demo: (Le Rossignol en Amour, van Francois Couperin)

Midi-file voor deze demo (file gemaakt door Xavier Verhelst).:

Building logbook / Bouwdagboek:

Omdat ons vaak wordt gevraagd hoeveel werk en tijd kruipt in, en nodig is voor, het bouwen van dergelijke muzikale robotten, houden we ook voor <Bomi> een beknopt en geilllustreerd bouwdagboek bij:

 

To be done:

Robodies Pictures with <Bomi>:

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Last update: 2023-10-07 by Godfried-Willem Raes

Technical data sheet and maintenance instructions:

Wiring tables for the three PIC 18F4625 controller boards:

Board 1:

board output connector pin mapping wire color remarks PIC pin
1 2 note 55 black pulse/hold 4,3
2 3 note 56 brown pulse/hold 2,5
3 4 note 57 red pulse/hold 6,7
4 5 note 58 orange pulse/hold 8,9
5 7

note 59

 yellow pulse/hold 10, 37
6 8

note 60

 green pulse/hold 36, 35
7 9 note 61 blue pulse/hold 34, 33
8 10 note 62 purple pulse/hold 30, 29
9 12 note 63 grey pulse/hold 28, 27
10 13 note 64 white pulse/hold 24, 23
11 14 note 65 black pulse/hold 22, 21
12 15 note 66 brown pulse/hold 15, 16
13 17 note 67 red pulse/hold 17, 18
14 18 note 68 orange pulse/hold 19, 20

Board 2:

board output connector pin mapping wire color remarks PIC pins
1 2 note 69 yellow hold/velo 4, 3
2 3 note 70 green   2, 5
3 4 note 71 blue   6, 7
4 5 note 72 purple   8, 9
5 7 note 73 grey   10, 37
6 8 note 74 white   36, 35
7 9 note 75 black   34, 33
8 10 note 76 brown   30, 29
9 12 note 77 red   28, 27
10 13 note 78 orange   24, 23
11 14 note 79 yellow   22, 21
12 15 note 80 green   15, 16
13 17 note 81 blue   17, 18
14 18 note 82 purple   19, 20

Board 3:

board output connector pin mapping wire color remarks PIC pins
1 2 note 83 grey pulse/hold 4, 3
2 3 note 84 white pulse/hold 2, 5
3 4 note 85 black pulse/hold 6, 7
4 5 note 86 brown pulse/hold 8, 9
5 7 note 87 red pulse/hold 10, 37
6 8 note 88 orange pulse/hold 36, 35
7 9 note 89 yellow pulse/hold 34, 33
8 10 note 90 green pulse/hold 30, 29
9 12 note 91 blue pulse/hold 28, 27
10 13 light note 120 grey hold (front) 24, 23
11 14 light note 121 green hold 22, 21
12 15 light note 122 purple hold 15, 16
13 17 light note 123 yellow hold 17, 18
14 18 light note 124 blue hold 19, 20



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

This is the same type as used in our <So> robot.

Parameter nr. setting comment
P0003 - User Access level 3
  • 1= standard (motor params.)
  • 2 = extended
  • 3 = expert
For normal operation must be reset to 0.
P0004 - access control filter params 0 allow access to all parameters of P0003 = 3
P0005 - display parameter 21 display motor frequency
P0010 - commisioning params 0

must be set to 1 to change motor params.

For access to P4 params and normal operation, must be set to 0
P0100 - Europe/ US 0 = default value (Europe, 50 Hz)
P0210 - voltage 230 V mains voltage
P0304 - nominal motor voltage 132 V motor specs. (motor is triangle connected)
P0305 - motor current 0.56 A motor specs.
P0307 - motor power 0.07 kW motor specs.
P0310 - nominal motor frequency 50 Hz motor specs.
P0311 - nominal motor rpm 2800 motor specs.
P0700 - ctrl. via control panel or digital I/O 2 use digital inputs for ctrl.
P1000 - select frequency setpoint 2 set analog setpoint (1= operator panel f-ctrl)
P1080 - min.. motor frequency 10 Hz  
P1082 - max. motor frequency 75 Hz  
P1120 - ramp up-time 2"  
P1121 - ramp down time 5"  
P2000 - max.frequency setpoint 80 Hz  
P3900 - end quick commisioning 1 resets P0010

Signals connection & pin numbering on the motor controller:

With the V2.0 firmware in the 18F2525 PIC controller, we get following correspondence between the controller #7 value and the motor frequency:

Controller 7 value Motor frequency

wind pressure

10 mm H20 = 1 mbar

 remarks
0 0    
5 8 Hz   no sound
10 14 Hz   motor standby, some pipes can make whistle sounds
15 19.2 Hz   this is the lowest limit for getting the pipes to speak
20 23.6 Hz    
30 30 Hz   pitch may be a quartertone down
40 36 Hz    
50 40 Hz    
55 42 Hz 43 mm H2O good for normal playing, but pitch will be a bit low
60 43.7 Hz    
70 46.5 Hz    
72 47 Hz 45 mm H2O this is the reference value for normal playing, tuning and intonation. A= 440 Hz
73 47.3 Hz    
75 47.8 Hz    
80 48.9 Hz    
85 50 Hz   this would be the nominal motor frequency
87 50.3 Hz    
89 50.5 Hz    
90 50.8 Hz    
95 51.8 Hz 50mm H20 this would be the nominal pressure for the given motor.
100 52.5 Hz    
110 54.2 Hz    
120 55.6 Hz    
127 55.7 Hz 65 mm H20  

The windpressure was measured in the windchest. The pressure measured in the output orifices for the pipes with the valve opened is always slightly lower.

 

Power supply wiring:

Circuit drawing for the midi-input and hub board:

This picture can be enlarged to full size, if required.

Wiring diagram for the above board:

Parts & components:

Pipefeet: Laukhuff order numbers:2 211 09, 2 211 10, 2 211 11, 2 211 12, 2 211 13

Conical valve pallets Laukhuff order numbers: 4 091 04, 4 091 05, 4 091 06, 4 091 07

type nr nominal diameter diameter with calopel coating milling angle height Qty. used
409100 49 mm 50 mm      
409110 43 mm 44 mm      
409101 38 mm 39 mm      
409102 34 mm 35 mm 110° 12.5 mm 1
409103 29 mm 30 mm      
409104 24 mm 25 mm 100° 11 mm 8
409105 18 mm 20 mm 85° 10 mm 10
409106 16 mm 16.5 mm 81° 8.3 mm 10
409107 12 mm 13 mm 72° 7 mm 9

Custom made mills: Lanoye bvba, Campus Zwijnaarde, Technologiepark 12, 9052 GENT. (091-2219337, mail: lanoye@telenet.be)

Valve solenoids: Laukhuff, 12 V type, DC resistance 80 Ohms. (the original flat pallets have been replaced with conical ones and the springs with custom made helical springs).

Softshift Solenoid data:

Vertical softshift solenoids for expressive wind pressure modulation mounted inside the windchest: Ledex Softshift type 5EP (now Saia Burgess), number 193015-026. Cold DC resistance 10.3 Ohm. Nominal working voltage at 100% duty cycle: 14 V.

For the working of this valve, taking into account the very low air pressure (normally 4.5 mbar, maximum 7.0 mbar), a voltage of 12 V is enough. The valve starts opening with a voltage of 2.6 V and is fully opened with 11 V.