#4 Cheap smart garage door opener with door sensor under $10 ($5 - $7): esp8266/ESP-01S.

It will actually cost $5-7, you don't need a $35 Raspberry Pi or $15 Sonoff. Correction: the GP0 pin in the Blynk app should be 1 to 0 (instead of 0 to 1) since the relay is active low. ESP Code: https://github.com/ungineer/esp8266garage Required Components: 1. esp8266 + relay: http://s.click.aliexpress.com/e/_d6bKGaU OR esp8266 + relay: https://s.click.aliexpress.com/e/_AUMwBc 2. magnetic sensor: https://s.click.aliexpress.com/e/_DmMc4XH 3. power supply w/o enclosure: http://s.click.aliexpress.com/e/_dU1bhas OR power supply with enclosure: https://s.click.aliexpress.com/e/_9Jl4QS Optional Component: double row male header: https://s.click.aliexpress.com/e/_dWzXPAC Blynk Getting started: https://blynk.io/en/getting-started A starter video: https://www.youtube.com/watch?v=nlpMUuyniWg --------------------------------------------- Music: Summer - Bensound https://www.youtube.com/watch?v=KxwUy2S2n-Q