Debug SONOFF AC relay with a thermal camera


James Lewis shares his experience in debugging SONOFF AC relay with a thermal camera:

The clever solution seemed to be clever, at least for a few minutes. Suddenly the light turned off. I thought maybe there was a timeout for the manual button. Annoying, but workable. The lamp remained off for about another 2 minutes when I started to smell that unmistakeable burning plastic odor. Touching the case of the SONOFF identified the culprit immediately.
Great. So I have an AC mains switch that isn’t working, but I do not want to go poking my multimeter into it. What do I do?
Turns out, that SONOFF module was defective. I wanted to debug it, but I did not want to measure anything while connected to AC. Here’s how I used a thermal camera to debug my SONOFF.

See the full post on Bald Engineer blog.

Programmable relay switch using PIC MCU (revised version)


Raj has documented his DIY programmable relay switch using PIC16F1847 microcontroller:

Here are the summary of the features that this programmable relay switch has:

  • On-board +5V voltage regulator (operates at 9-15V DC input)
  • OFF and ON time setup for the relay operation
  • Option for cyclic run (maximum 100 cycles, after which the timer stops automatically)
  • Stores ON/OFF times and Cyclic option from previous setup into internal EEPROM
  • ON/OFF timing range: 0 to 99 hours and 59 minutes with 1 min resolution
  • Interactive user interface using 4 tact switches and a character LCD
  • On-board buzzer alarm

More details at Embedded Lab site.

Check out the video after the break.