Switch relays on and off from a few kilometers
This is an Arduino project with the following purpose. I want to turn on and off a high power electric device from a few hundred meters. The cheapest and easiest way to do so is to use handheld radios aka. walkie-talkies.
The circuit consists of an Arduino Uno, a relay board, an SSD1306 128x32 OLED screen (as a VU meter), a 500R series resistor, an antiparallel diode pair and a walkie talkie. The circuit is simple:
━━━━━━━━━━━━━┑ ┏━━━━━━━━━━━━━
+ ┃━━━500Ω━━┯━━||━━┃ Ain
Radio ┃ ┃ ┃ Arduino
headphone ┃ ▲ ▼ ┃ Uno
out ┃ ┃ ┃
- ┃━━━━━━━━━╋━━━━━━┃ GND
━━━━━━━━━━━━━┙ ⏚ ┗━━━━━━━━━━━━━