[artdutra04]

Another thing to remember about pneumatic solenoids is that they are either single-acting or double acting.

A single-acting solenoid has only one solenoid, and has two wires coming out of one side of the solenoid. A double-acting solenoid has two sets of red/black wires, one coming out of each end.

On a single-acting solenoid, if you provide no electricity the input will always be aligned to one specific output. If you provide the necessary voltage to the solenoid it will change to the output output as long as that voltage is held. If you lose power or the solenoid is disabled at the end of the match, the solenoid will always return to the no-power state. This is how some teams have "after the buzzer" mechanisms - when the robot is disabled the solenoid returns to its off state.

A double-acting solenoid will hold its position regardless of the current electrical signal. If electricity to both solenoids is off, the input-output will remain unchanged. If you apply electricity to ONLY the left solenoid, it will push the valve to the right and make output1 active. If you turn off the left solenoid and apply electricity to ONLY the right solenoid, it will push the valve to the left and activate output2. Don't turn on both solenoids valves at once, you will get unpredictable results. Double-acting solenoids are useful for holding a specific position when the robot is disabled.