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

[Andreas Gaunitz]

2004 dec 08  kl. 04.03 skrev Ken Stone:

> The problem with this diagram as shown is you will find the movement  
> of the
> solenoid too short to be practical.

Do you think so? Some of these solenoids have a stroke length of 0.7  
inch (about 1.75 cm).
http://www.mpja.com/viewallpict.asp?dept=160&main=


> The reverse "C" hammer/damper is okay, though you will probably need  
> to move
> the solenoid to the right, and have a pivot point even further to the  
> right
> than that.
>
> H------S--P
>
> where H= hammer, S =  solenoid and P = pivot.


OK. I wasn't going to have a pivot point, but let the whole  
construction travel up and down. But maybe it's a good idea, to get it  
more stable: (please note the Damper-on-a-stick solution for shorter  
travelling solenoids he he)


                   DDDD--------+----------+
                   DDDD        +--------+ I
                                        I I
                                        I I
                                        I I
+------------------------+             I I
+-- Xylophone bar -------+             I I
                                        I I
                                        I I
                    BB                  I I
                   BBBB/\/\/\/\+--------+ +------+
                    BB         +--------++-------O  <--Pivot
                                        II
                                        II
                                        II
                                        II
                                     +------+
                                     I      I
                                     I      I
                      Solenoid  -->  I      I
                                     I      I
                                     I      I
                                     +------+















>> 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
>>> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
>>> Australian Miniature Horses & Ponies  
>>> <http://www.blaze.net.au/~sasami/>
>>>
>>
>>
> _______________________________________________________________________
> Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>