# Contorl Solenoid direct from computer

Can we control a pneumatic solenoid direct from the robtic computer?

I dont think so. I think that they have to go through a spike first but i’m not entirely sure about it. Hope this helps

I know things work through a spike and we have that working well but we are down to shaving ounces and if we can take two spikes out yea!

if there are two solenoids that do the same thing, you could make a T connector to put them on one solenoid. this would allow you to take off one spike.

Tell me more please…A t connector?

No. The solenoids require about 100mA at 12 Volts. The RC puts out 5V, and I can’t remember what the current limitation is.

actually you can control a double solenoid with ONE spike as opposed to, two. All you need is two rectifier Diodes, and the double solenoid (along with some crimps, wire cutters, blah, blah, blah)

the double solenoid has two 12volt coils on it (I hope)… so take a red from one side, and a black from the other side and crimp them together… Then take the left over black and red, strip the wire, and solder the diodes to each wire. Make sure they are in opposite direction as well. On the diode,the side with the line on it should be soldered on the black wire coming from the double solenoid and another diode should have the red on the non-lined side… (note - this is backwards because the current is coming from the other side) … Then solder some wire onto the other side of the diodes, strip that wire, and crimp it together. Personaly I put the side with diodes on M+ and then non diode side on M-. You save weight, and also simplfy program by use of only one relay.

if this is Relay1 and you only want it on when the button is depressed then… If (p1_sw_trig ==1) {
relay1_fwd = 1;
relay1_rev = 0;
}

else {
relay1_fwd = 0;
relay2_rev = 1;
}

so you save weight and code is simplified

good luck

Very cool, and I hate to be a wet blanket, but I think that would be forbidden, since a custom circuit (which that technically is I think, though my memory of the wording of the rule is fuzzy) isn’t allowed to directly control the outputs, that of which being a solenoid. Since it doesn’t actually allow the solenoids to react without the RCs cooperation anyway at the same time I’d think it’d be legal, but I also have a feeling that the wiring rules may also forbid your modification, can somebody else clarify?

you dont even need the diodes, they have them built in, just hook one up backwards and your good to go.

• Bochek

oh yea, come to think of it we only did for the coils w/o removable wire pieces. Good point

If you are going to actuate the solenoids at one time - you can just use one spike and one solenoid and T the pneumatics lines off of the solenoid.

That would minimize your weight and avoid custom curcuits.