SOS station toy with yellow and blue LEDs
A while back my kids got this SOS station toy, it came with a few emergency cars and the boys quite liked it. My girl friend and myself however; hated it, it had a speaker and made a high siren sound and an annoying voice would shout things like "all cars respond". So I modified it; ripped out the speaker and mounted a few LEDs instead, so now it flashes but no sound.
Originally it had a blue light on the roof, a speaker and four buttons; pressing them would make a siren noise and a voice would start talking/yelling. And the blue light would blink for a few seconds. There was also a "walkie-talkie" thing connected to the speaker. Pretty annoying stuff.
I removed the electronics inside, the speaker, "walkie-talkie" and buttons, kept the blue light but replaced the light bulb with a self-flashing LED. I mounted two yellow LEDs in the roof over the "car port" area, also self-flashing. I plugged three of the four holes where the old buttons had been with rubber gaskets and mounted a toggle switch in the the last one. This turns all the LEDs on and off.
I reused the battery holder, it fits 3 x AA batteries in series, which gives a voltage of 4.5 volts. This is a bit too much for the LEDs, so a few resistors were required. And that was pretty much it. It now flashes yellow and blue when turned on, and does not make any noise. Perfect :)