Silenoids for Digital Key Hanger

the expression "a hair up your a--" fits me well... i got the idea to make a computer app where i click a picture of the thing i want keys for, and the keys for it fall off of a piece of cardboard (later a key lock box)

i want when i click a picture, it powers a solenoid, and it basically sucks in the pin holdign the keys... i cant find cheap, small solenoids... i would like them to be 5v...

If you are in or near the Phoenix area, have you tried Apache Reclamation and Electronics (3rd Ave and Apache)?

You could also try Goldmine:

or All Electronics:

There are also solenoids in regular "ding-dong" chime (non-electronic) doorbells (probably not the cheapest option, but you can sometimes find them at yard sales, thrift stores, and flea markets).

Lastly, there is always the option to hand wind your own solenoids (use thin magnet wire for the best results).


Very cool project idea. You know instead of looking for inexpensive surplus solenoids, why don’t you consider a bulk buy of cheap Asian servos on E-bay. Probably not the greatest quality, but for turning a lever to drop your car keys I bet they would work fine and at $4 a pop for 10 with free shipping, it’s hard to beat.

I’ve bought many things from Asia parts suppliers on E-bay and so far have had no problems. Delivery can be a bit, generally around 10 days for me on the west coast of the US.


These are probably about the best low-priced fit you'll find for your needs: there aren't a whole lot of 5V solenoids on the surplus market, the ones from Goldmine are fairly easy to drive with something like a ULN2003.

Don't forget to figure out how you will get the keys back in place :-)

i need pull solenoids, not servos, sorry...

Don't forget to figure out how you will get the keys back in place

i figure thats the last part...

The servo idea is actually not a bad one - just hook up a piece of rod to an articulated linkage that connects to the servo, have it turn a bit one way to pull the rod thru (and drop the keys), wait a bit (or perhaps wait to "hear" the "thunk" of the keys dropping?), then turn it back to push the rod back thru.