Linear LED ammo Counter?
So, my friend and I are building a Coil Gun! Nothing super powerful, but it will punch a nice hole in a cardboard box. Here's the problem; we want to add an ammo counter to it. We were thinking of using an IR LED, a Photo-transistor, and a voltage comparator circuit, kind of like the one here (http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html
, first photo, right circuit)) . The circuit would send a pulse when the projectile interrupted the IR beam. Now what? The magazine holds 6 rounds, so maybe 3 green LEDs, 2 yellows and 1 red to count the ammo. We were thinking of maybe using a 4017 counter IC to advance down an LED after each pulse, but doing it this way means only one LED is lit at a time. We would really like it if somehow we could have all the LEDs lit, and after each pulse one would turn off, but I'm unaware of how to do this. Oh yea, we don't have access to a micro-controller, which is why we have this problem. So to recap, we need a circuit that will light 6 LEDs when powered on, then shut off one LED for each pulse received. Is there any way to make a circuit that does this?