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.

Ripping out all of the original electronics

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.

Mounted new switch, and covered up the unused holes

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 last one. This turns all the LEDs on and off.

Wiring up the new switch and LEDs, I’m reusing the battery holder

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 🙂

Soldering the yellow LEDs
Blue LED, soldered and glued down

Here are the parts I used:

  • 1 × LED 5mm clear, flashing Blue, 3.0-3.4V, 20mA, 7000-8000mcd, 20°
  • 2 × LED 5mm clear, flashing Yellow, 1.8-2.2V, 20mA, 4000-5000mcd, 20°
  • 2 × LED holder 5mm, White plastic
  • 1 × Resistor, carbon film, 0.25W, 75 Ω, 5%
  • 2 × Resistor, carbon film, 0.25W, 150 Ω, 5%
  • 1 × Switch, toggle, 1-pole, micro, MTS-102, on-on, 6mm

Last commit 2023-12-25, with message: replace emoji slight_smile/slightly_smiling_face