Hello all,
I'm creating an electronic organ that has about 50 or so draw knobs. (A draw knob on an organ is what you pull out to add sounds and push in to take away sounds). Each stop has to have a solenoid to pull it in and out, so I'll need about 100 or so solenoids. But I have no idea how to power them. The solenoids will be about 9 or 12 Volts, and they need to be driven by a 1-3 volt signal from an I/O board. I will have to be able to power at least 40-50 of them at once. They will only have to push/pull between 5/8 and 1 inch horizontally, with probably less than 10 ounces. I'm trying to do this for as little money as possible. I read on other articles that old VCRs have solenoids so I'll look into that. But I was going to wound each solenoid myself, do the wiring, and just buy an I/O board.
So ultimately my question is how do I do this?
Thanks
Ray

 

I wonder if you would not be better off using servos rather than relays. If you use relays they are going to require a lot of power depending on how many relays you need to energize at the same time.

hgmjr

 

Would mosfets work?

 

If you use relays then mosfets are a good choice to drive the relays.

hgmjr

 

So how would I connect these?

 

A typical circuit for driving a solenoid is shown below. I don't think you should take on winding your own. You may find it tough locating a relay that runs on 3Vdc.

hgmjr

 

So I need a relay and a mosfet per solenoid? And could you describe the different parts of the circuit diagram?
Thanks!

 

If it is an electronic organ, then why cannot the stop operation be done with electrioncs rather than brute force? I have one solenoid that can deliver maybe 10 oz over 5/8 in, 12V @ 2A, $ 5.00[ out of stock ] but it is just pull, would take two for push-pull without using spring return & continuous power to hold position. Maybe there is a push-pull solenoid using a perm mag armature allowing polarity for position reversal.

 

Look into pinball machine flipper solenoids (with their spring return assembly.) A second winding permits "holding." Many take a coil voltage higher than 12V but they are reasonably simple to drive with a MOSFET (logic level) from a uP. I used them awhile back to ding tuned pipes.

joe

 

solenoids are pricey ($20-30) but if you make you own cost can vary quite a bit.

to drive solenoids, you can use discrete transistors such as shown in post 7 for example but check the current requirement, you may be able to use ULN drivers (should be much cheaper, and if needed you can parallel the channels).
to control them, one can use shift registers so any microcontroller could do the job.

servos are interesting alternative (though slower) but don't think i've seen 100 servo in one project.

 

What do these draw knobs do electronically to "add sounds" and "take away sounds"?

pilko

 

' had no luck in finding true push-pull solenoid; found allusion to perm. mag. plunger but no product. Another possibility is a shoot-thru solenoid where solenoid is open on both ends, first pulse shoots plunger clear thru to a stop on opposite side; second pulse returns plunger to starting position. Tried it out on homemade solenoid- see thread started by Bernard, " I Made a Solenoid".