About 6 months ago, I started working on an electronic air-soft turret. My friend Thomas was looking for a computer vision project, and I had recently shown him a project by a guy from my home state, who does some really amazing write-ups. Check out some of his other stuff while you’re there.
Anyway, we ordered a pair of electromechanical airsoft guns and two servos, and after a weekend we hacked together a simple pan/tilt axis turret. Fire control is provided by a single MOSFET, and the firing motors are wired in series so I can actually switch enough current to turn them. (They run at a whopping 3 amps!) Overall the circuit is very simple. However, I’m getting large amounts of noise that are causing the servos to lose power when the gun is fired. Considering how much power is going through those motors and their low resistance, I’m not entirely surprised. To fix the noise issue, I put a reservoir capacitor across the servos, and a diode from the servo control section of the board to prevent any current flow from pulling the ground side of the servos up. Unfortunately, rapid firing will still cause the gun to go limp, but it’s much more tolerable for ~10 shots.
What I have right now is a mouse controlled demo that lets you pan/tilt with the mouse and fire with left click. Thomas is working on his vision software, but considering the innovation fair is tomorrow (holy crap!) I don’t know if we’ll get it working*. Here’s to hoping.
*Ed note: He didn’t finish his implementation yet. See the next post for a few more details.