Unplugging microdamper fried my Pi Zero

[JanW]

Hi All!

Want to start by saying thanks for all the really great efforts you are putting in to create the heatermeter and the associated dampers!

Over the last weeks I have sourced all the parts in The Netherlands and have built a Heatermeter and a Microdamper. All came together really well! Even the SMD soldering for the TC stuff wasn't as scary as I thought it would be .

I did run into one issue I wanted to share. Yesterday while testing, I accidentally unplugged the TRRS jack from the microdamper whilst the fan was running. Immediately, the LCD went blank and the unit stopped working, furthermore a burnt smell came from the device.

A quick inspection learned that the RPI Zero was cooking. Unplugged the pi, and gladly the HM unit still worked perfectly well . I tested the RPI separately, it refuses to boot and gets really hot real quick. Some reading indicates that probably the 12v ended up at the RPI somehow.

I ordered a new RPI and will be very careful with the TRRS jack from now on. But I still wonder how this could have happened, should it be possible to blow up the RPI by unplugging the jack? Or do I maybe have made a mistake somewhere that could be the cause of this happening... What do the experts think?

 

[Steve_M]

I’d probably just make a pigtail with an rj45 jack and ditch the TRS jack.

 

[JanW]

Thanks for the suggestion . I decided to ditch the connector as a whole, and just fed the ethernet cable through the hole, and used a tie wrap on the inside to take tension of the connections in case someone pulls / trips the cable.

 

[Bryan Mayland]

Thanks for the suggestion . I decided to ditch the connector as a whole, and just fed the ethernet cable through the hole, and used a tie wrap on the inside to take tension of the connections in case someone pulls / trips the cable.

I had concerns about the TRRS connection and if this was a possibility so I did the same thing. Just run the ethernet cable right in, through a grommet:

I also put a couple zipties inside for strain relief so the cable can't pull out.

 

[JanW]

just run the ethernet cable right in, through a grommet:

Thanks Bryan! Added a grommet as well now . Makes it look a little more neat, and prevents air from leaking in.