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Topic: Lots of cheap solenoids or something similar (Read 2 times) previous topic - next topic


Would servos work to move a valve?
Can be had for as low as $8
Mega can drive 48 servos I think I recall reading.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.


It depends on where you shop. I can probably beat these below btw:

12 Vdc, 100mA solenoid valve. Open when activated. Body: 24mm diameter x 31mm long. 62mm overall length, including inlet and outlet ports and terminals. 0.19" diameter ports. Used, removed from equipment.

$2.50 ea.

Analog servo motor. Standard size, 1.55" x 0.73" x 1.46" (39.4 x 18.5 x 37.1mm). 49oz-in torque @ 6Vdc. Speed: 0.23sec/60 Degrees @ 4.8V, 0.19 sec/ 60 Degrees @ 6V. 6.5" leads with standard 3-conductor female connector.

$6.95 ea.

Ledex(TM). 0.5" diameter x 1" long tubular solenoid with 3/8" diameter threaded bushing for mounting. 1/16" diameter x 1/2" long plunger. 40 Ohm coil. Operates on 12 Vdc. 1" wire leads.

$2.75 ea --- some caveats, provide your own return action and armature hold


A customer from CA US
armature not attached
I haven't used these in an application yet, but it should be noted that the armature (the actuating pin of the solenoid) is not retained within the solenoid body. In other words, if there is no power to the device, the pin can fall out the back. If you plan to mount the solenoid vertically (with the pointy end facing upwards), you will need to have something behind the solenoid to keep the armature from falling out.

A customer from Midwest USA
Wimpy little solenoid
Very limited push power. Maybe 1/8 inch of stroke is usable for any kind of push. Will push very lightly on 2 D batts, stronger on a 9 volt batt and a bit more on a 12v SLA. Still wimply and no way to hold in the piston from falling out.

A customer from Canada
removable body?
can anyone tell me if you can remove the body or outer shell from this solenoid? all i need is the coil inside.

A customer from Near Sacramento, CA
Doesn't have spring return
The solenoid does not have a spring to return it to a retracted position when power to the solenoid is cut. Like the other reviewer mentioned, it does not have a back to keep the pin in when turned upside down (so that the pin pushes up when power is applied). I mounted the solenoid upside down (making sure the rod didn't fall out the back) and the solenoid would not always retract with the force of gravity after I triggered it. I was able to drive it with 5V and 9V and it has nice holding force.

I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.


I have the parts from a magnetic toy that I bought a few years ago. It consists of little plastic "sticks" with a magnet each end and steel balls. You can build interesting shapes with it. I can't remember what it was called but I see similar things on Google called Geomag and Manetix.

In the parts I have it is easy to take the little neodym magnets out of the sticks. They are about 4mm in diameter and 4mm high. They might fit through the centre of your bobbins.



May 31, 2013, 09:22 pm Last Edit: May 31, 2013, 09:25 pm by stoopkid Reason: 1
It would have to go down to less than a dollar before I could consider buying what I need. Even making them myself I have to be really cautious with what I pick.

Found a few different sizes nails, even some really big ones for pretty cheap and some new thread spools that are longer and should allow larger nails to pass through. If the nails are too heavy I might make the solenoids the moving part.


Jun 01, 2013, 01:25 am Last Edit: Jun 01, 2013, 01:33 am by GoForSmoke Reason: 1
Thread spools.... You want the windings close to the armature.

Small diameter spools might be okay but every mm between windings and armature takes away effect, the fall-off is fast. For some bobbins you would be better off with cardboard or rolled card stock and tape.

Here they make strong solenoid and measure move force vs hold force.

Adding: and of course you put a capacitor across power and ground at each coil and I think a diode, all for circuit protection, right? ULN28xx Darlington driver chips have that built-in btw.
I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

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