I'm building an 8 stage coil gun for a physics project, and I want to verify this circuit as I've never used a phototransistor before and I'm still pretty new to mosfets. Here is a schematic:
The idea is that when the projectile (a penny in this case) crosses between the ir led and the phototransistor, the coil triggers until the penny exits the photogate. It will also light the 6 2v red LED's for the duration. I'm not sure that Iwired the mosfets to the phototransistor properly. I know that the load should be attached between v+ and the collector of the phototransistor, but that would require routing the potentially 100 amps of coil current through the phototransistor and remove the purpose of even having the mosfet there. would putting a pullup resistor between the collector and 5v and attaching the Mosfets' gates to the emitter work as intended?
As a side note, the coil will only be on for a tiny fraction of a second. If I hook up the red LED's to the red channel of rgb LED's that have blue on constantly, will a purple wave travelling down the stages be visible, or will I need to extend the red channel pulse? I could use a capacitor charging circuit between two NAND gates I guess, but I want to minimize unnecessary circuitry so it can all fit in a small-ish package.
Thanks for the help; I'll probably be back shortly with some troubleshooting for the actual coils haha.
EDIT: this is the phototransistor I'm using: https://www.sparkfun.com/datasheets/Components/LTR-301.pdf
EDIT 2: could I hook up 12 v to the phototransistor, or would I risk overvolting the mosfet? I need to break the mosfet's activation voltage, which the pullup resistor might prevent from happening.... Also not having to route a 5v line helps.