The cap used in this application is just for noise filtering. If not using the mosfet it is not needed. Like you said - it is quite large.
I am goingt to build a new start gate for the scout track and eliminate the computer interface - and just use the pushbutton to activate the soleniod/start gate.
The curcuit is REAL simple then. A 12V power supply - a 12V solenoid or car door lock actuator - and a pushbutton to activate.
I do reccomend the diode across the soleniod revered biased (stripe or band towards the positive side) to shunt the voltage generated as the magnetic field the make the soleniod plunger move collapses. You will also need something to mount the circuit to and a plug/jack set for the power supply.
Note most everybody will have a suitable power supply around thier house already. Take a look at the block that plugs in for any of you electronics of your kids electonics. Each one will list the OUTPUT voltage. You want to find one in the 11-13v range. Likely a 9v on would work but I reccomend something closer to the 12V if possible.
I am goingt to build a new start gate for the scout track and eliminate the computer interface - and just use the pushbutton to activate the soleniod/start gate.
The curcuit is REAL simple then. A 12V power supply - a 12V solenoid or car door lock actuator - and a pushbutton to activate.
I do reccomend the diode across the soleniod revered biased (stripe or band towards the positive side) to shunt the voltage generated as the magnetic field the make the soleniod plunger move collapses. You will also need something to mount the circuit to and a plug/jack set for the power supply.
Note most everybody will have a suitable power supply around thier house already. Take a look at the block that plugs in for any of you electronics of your kids electonics. Each one will list the OUTPUT voltage. You want to find one in the 11-13v range. Likely a 9v on would work but I reccomend something closer to the 12V if possible.