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Robot Drummer (of Wahappen rock and roll band) 



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Robot Drummer (of Wahappen 
rock and roll band) 

Written By: Tim Laursen 

SUMMARY 

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The drum machine is a simple MIDI device that has a "MIDI out" connection. This sends a 
MIDI signal, which is made of 128 different "notes", to a MIDI decoder (HIGHLY LIQUID 
MSA-R). The MSA is capable of turning 8 of the MIDI notes into "on/off" switches. So I made 
a drum beat and assigned the kick drum=#1, snare=#2, rack tom=#3... then I built 8 robot 
arms with solenoid motors and attached them to the MSA. When the drum machine plays a 
kick it sends MIDI note #1 to the MSA which closes one of its relays completing a 24Vdc 
circuit for 50 milliseconds (ms). This pulse length is adjustable. This is long enough for the 
solenoid to energize and close, causing the drum to be struck, and then release, the same 
way you hit a drum with a stick. I should note that we added a Darlington transistor circuit 
outside the MSA so we could use bigger solenoids that draw more amps without damaging 
the MSA. The transistors are all TIP 122's. I got some great help to figure this out and now I 
am going to make more and better robots this summer. 

I am in Brooklyn. Come visit our shop, please! We are a two-piece band about 6 months old. 
This is our first robot drummer. I am working on a second now using pneumatics and flame 
throwers. I want to find people in Brooklyn to make with. 

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Robot Drummer (of Wahappen rock and roll band) 
everyone loves fluorescent paint 

This document was last generated on 2012-1 1-03 04:23:23 AM. 



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