Percussion Robot

Research project on the development of tools for musical expression



an automated pair of shakers

dr.Godfried-Willem RAES


[Nederlandse versie]


An automated pair of shakers made and designed to the order of Stef Kamil Carlens. Earlier designs for automated shakers we realised, can be found in the robots <Springers>, <Hat> and <Whisper>. At first sight, automating shakers seems to call for either a motor capable of fast CW and CWW operation or a bidirectional solenoid. As we had not too good experiences with motors -too slugish and if fast, way too noisy- we looked into bidirectional solenoids as used for the maracas in our <Springers> robot. Unfortunately though, the factory where we bought these parts -August Laukhuff Gmbh- went out of business in the summer of 2021. Apparently their activity has been taken over by Heuss Gmbh, but our attempts to order from them failed. We didn't get any response on our requests... As an alternative, we realized a bidirectional mechanism by using two unidirectional solenoids. The Tremba type ZMF3865d looked like a viable component. This solenoid is specified to operate at 24 V with 100% duty cycle. It then consumes a power of 11 W. So, calculated resistance should be 52.4 Ohm. If duty cycle is limited to 5%, after the data sheet, we can dissipate up to 220 W. Calculated voltage from these values gives 107 V. The required trajectory for the anchors is 20 mm. The force delivered by the solenoids, with 107 V applied, is then 30 N. The optimum trajectory for this type of solenoid is 15 mm, whereby they give a force of 40N. These considerations lead to a power supply dimensioned like this:The +24V power supply is used for the holding force, whereas the negative supply is used for the pulses only. Required current is quite high, but only needed for very short time intervals.

The circuit for steering the four solenoids resembles the one designed for the valve control used for our robotic brass instruments, but obviously the firmware turned out to be completely different. The processor ports RA4, RC0, RC2 and RC5 are used to switch the 24V hold valte on. On the ports RA5, RC1, RC3 and RC4 the high voltage pulses are generated to steer shaker attacks with high precision. A high pulse on these outputs, switches the corresponding solenoid on between the 24 V and the -85 V power supply lines. Thus the voltage over the solenoid is effectively 109 V.

Mechanically, we performed a lot of expertiments to find out what kind of mechanism works -and sounds- best, also taking into account side noises originating from different sources of faults and imprecisions plaguing just about any mechanic construction.

Midi Mapping and implementation:


Note 60: Shaker1 forward, velocity byte steers the attack force

Note 61: Shaker1 backwards, velocity byte steers the attack force

Note 62: Shaker 2 forward, velocity byte steers the attack force

Note 63: Shaker 2 backwards, velocity byte steers the attack force

Note 72: Shaker 1, toggling over and back, velocity byte steers the attack force

Note 74: Shaker 2, toggling over and back, velocity byte steers the attack force

Notes 120, 121, 122: lights


Controller #60: Hold time for shaker 1 forwards
Controller #61: Hold time for shaker 1 backwards
Controller #62: Hold time for shaker 2 forwards
Controller #63: Hold time for shaker 2 backwards

Controller #66: Power on/off., Power ON resets all controllers.

Controller #69: light automation on or off.

Controller #123: All notes off, reset.

Still subject to changes.


Technical specifications:

Design and construction: dr.Godfried-Willem Raes

Collaborators on the construction of this robot:

Music composed for <Shak>:


Pictures taken during the construction in our workshop:



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Dit automatiseringsprojekt ging van start op vraag van Stef Kamil Carlens. Het maakt dan ook geen deel uit van ons grote projekt rond de bouw en ontwikkeling van het robotorkest. Shakers zijn voor gebruikers van het robotorkest beschiklbaar, onder meer als deel van de <Springers> robot.


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Last update: 2021-11-07 by Godfried-Willem Raes

The following information is not intended for the general public nor for composers wanting to make use of the <Shak> robot, but is essential for maintenance and servicing of the robot by our clients and collaborators. It also might be usefull for people that want to undertake similar projects.

Technical drawings, specs and data sheets:

Power supplies:

Wiring & circuit details midihub board:

Circuit details solenoid driver board:

Here is a picture of the assembled board: (the 5V relay is not yet mounted on the picture). And, this is the solder side:

Solenoids: Tremba Gmbh, Zylinderhubmagnet, ZMF-3865d-15.002-24VDC. Datasheet.


Tentative cost calculation:

1. Materials and components

tubular solenoids: 4 ZMF-3865, 24V DC - 100% - double threaded 116,00- 464,00-
PCB Hub & P/H board: 1 250,00- 250,00-
Power supply 24V 100,- 100,00-
Power supply 100V (toroidal, Kemet elco 12mF - 200V) 250,- 250,00-
Chassis stainless steel 200,- 200,00-
Draadstang, M10, inox   8,00- 8,00-
Verbindingsmoeren M10 inox      
M10 inox moeren 6    
M10 inox eindmoeren 2 3,50- 7,00-
M4 studs and dampers 8 4,20- 33,60-
M3.5 x 8 boutjes en moeren, inox 25    
M12 inox bouten en moeren 2 4,00- 8,00-
M5 X 80 cylinder bouten 4 3,30- 13,20-
M5 x 16 cyclinder bouten 2 0,90- 1,80-
M4 x 16 cyclinder bouten 4 0,60- 2,40-
M3 x 30 bouten + 10 mm afstandsbussen 4 1,80- 7,20-
Material cost estimate      

2. Consumables

Cobalt drill bits 1
TIG welding materials Argon gas and Tungsten/Thorium electrodes
Cutting disks 2 (A60 T-BF41 125 x 1.0 x 22.2)
Flap disc, 160mm 1
Sanding disks and paper 1
TIG welding nozzle, nr.5 1
Cutting oil (spray can) 1
Solder Pb/Sn 40/60 & leadfree 5 m
Aceton 0.5 l
Etching baths Fe2Cl3 1 liter
Methanol 0.25 l
NaOH sollution 0.5 l

3. Depreciations on tools and equipment used (calculated over 1 month)

Tool Value Depreciation percentage / month
Tektronix TDS2024C 3500 2.77%
TIG welding equipment 2000 2.77%
Contimex Lathe 2500 2.77%
Cobalt saw 2800 2.77%
Soldering equipment 1000 2.77%
Proton+ Laptop & ICD 1800 2.77%
Lab power supply 380 2.77%
Odin column drill 6000 0.92%
Welding table 2500 0.92%


4. Labor and design (45,-/hour)

06.10.2021 2 h
18.10.2021 2 h
19.10.2021 8 h
20.10.2021 4 h
23.10.2021 4 h
24.10.2021 6 h
26.10.2021 6 h
27.10.2021 8 h
29.10.2021 2 h
01.11.2021 9 h
05.11.2021 3 h  
06.11.2021 8 h  
07.11.2021 12 h  

Labor (estimated at 3 weeks): 3.150,-

Total estimated cost: xxx,-


Raes, Godfried-Willem, "Expression control in musical automates", 1977/2021
Raes, Godfried-Willem, "Logos @ 50, het kloppend hart van de avant-garde muziek in Vlaanderen", 2018