[sdiy] Kinda OT: electro-mechanical instruments/ solenoids

[Andreas Gaunitz]

Excellent notes, thank you. I want it to be played from a (midi or CV) 
keyboard so that when a keyboard key is released, the corresponding 
xylophone bar is muted. I have an idea that looks like this:


                            +-------------+
                            +-----------+ I
                          DDDDD         I I
                           DDD          I I
                                        I I
+------------------------------+       I I
+-- Xylophone bar -------------+       I I
                                        I I
                                        I I
                    BB                  I I
                   BBBB/\/\/\/\+--------+ I
                    BB         +---++-----+
                                   II
                                   II
                                   II
                                   II
                                +------+
                                I      I
                                I      I
                                I      I
                 Solenoid  -->  I      I
                                I      I
                                I      I
                                I      I
                                +------+

Where
1) DDD is a dampening material - cotton pad or rubber
2) BBB is a "heavy" bead mounted on a spring
3) Key on -> solenoid extends upwards, hits a full stop a few 
millimetres under xylo bar, bead hits xylo bar due to inertia, spring 
pulls the bead back
4) Key off -> solenoid retracts down, cotton pad dampens xylo bar


regards
-Andreas


2004 dec 07  kl. 09.12 skrev Ken Stone:

> My advice, for what it is worth-
>
> do not use a rigid set-up for striking. I used 1/8" cane with 3/4" 
> wooden
> beeds glued on the end for strikers. When the solenoid is in its 
> activated
> position, the bead is above the metal bar, not touching it. When the
> solenoid is activated, the momentum of the bead causes it to hid the 
> metal
> bar, and the flex of the cane will lift it clear. It sure beats trying 
> to
> electronically time the drive pulse to prevent the striker from 
> damping the
> bar after it hits.
>
> Ken
>
>> Hi!
>>
>>
>> I'm planning to build electro-mechanical instruments; xylophone etc.
>> Not really a synth, but close enough (?)
>>
>> Background:
>> In Sweden (a small country) the cheapest solenoid seems to be about 12
>> USD/ EUR. In the US some companies offer solenoids for less than 1 
>> USD:
>> http://www.mpja.com/category/Solenoids/Solenoids.asp
>>
>> The above company wants me to shop for at least 100 USD to ship
>> overseas. This in itself is OK, I could always buy a soldering station
>> or whatever. But how do I know that the solenoids are going to work in
>> my project? I need about 30 of them, but it would be nice to check one
>> out before ordering. Needless to say, the same brands don't exist
>> here...
>>
>> Question:
>> What should I look for in a solenoid? Do some solenoids have too slow
>> response times? Could they be too weak? Why are some so cheap compared
>> to others?
>>
>>
>> any input appreciated
>> -Andreas
>>
>>
> _______________________________________________________________________
> Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
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