Awesome, Dave! Thanks! I’m going to have to order some parts before I can give it another test run. In the meantime, I’ll work on cleaning up my schematic. To be continued…
EDIT: I see the 4N25 provides a pin out to the base of the transistor. Do I need to connect anything to that or is that just there to be able to provide alternate means of closing the circuit?
Also, I’m not sure I fully understand the switch. Is that there to only be used when initially turning on the power? So, I would plug in the USB with the switch off then when the LED is lit I would then turn on the 12V supply?
Question, isn’t the Pandas pin I/O’s high state 3.3v ?
My question is for the motor driver board. what input voltages will it accept 3.3 or 5v for a high.
EDIT: I went ahead and soldered the bridge and tried it with the rest of the circuit still as-is. It didn’t help anything although I’m sure it will be more reliable now. Looks like I’m still waiting on parts…
@ ianlee Your original circuit should work just fine. The transistor is the wrong way round though. Just flip it on the breadboard and see what happens. It may be damaged now because you drove it hard “in reverse”.
What transistor are you using? Some TO92 are EBC and other CBE looking from the front.
You can make it a lot easier by driving the solenoid directly with a Darlingon like a TIP120.
You guys rock! I flipped the transistor around (a 2N3904) and added the capacitors around the VR. I forgot to remove the 10K resistor while I had the board off but it doesn’t seem to be causing any problems. Everything is working perfectly now.
My end goal here is to end up with a PCB. So, I’m still interested in ideas for improvements. Should I worry with the optocoupler if the transistor seems to be working fine?
I like the sound of this. So, this would eliminate the transistor and the relay?
@ realiser, Yes you are correct, but I didnt know the transistor type or the coil resistance. Using a coil resistance of 120 Ohms,(my guess) and a base current of 3.3mA (3.3/1k) a min current gain of 30.3 is required, which means the 2N3905 is capable. However my solution, to me, is much safer ;D
Just a quick update on the Zombie gun presentation. I found out today that I’ve been selected to present it at DevLink this year! Get your tickets while you can. It usually sells out. It looks like there’s also going to be another Gadgeteer presentation this year by William Wallace.
