Steve writes –
I am learning about electronics by building a toy laser gun. This is the sound and light effects circuitry in development. The top board has a 555 monostable timer, which turns on a bright red LED, a laser, and the sound effect. It also triggers a second board, which has 555 oscillator which is triggering a 4017 decade counter chip. That circuit is the blue LED chaser. I have it timed so that it goes one cycle during the time that the trigger from the first timer is high. Whew! a lot of work to turn on a couple of blinky lights.
Homebrew toy blaster – Link.