Debug SONOFF AC relay with a thermal camera

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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)

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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.