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CCHS-Melbourne / iotuz-esp32-hardware

Project for the InternetOfTuz (LCA2017 Open Hardware Mini-Conference)
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BME280 placement causes temp readings 10C too high due to chip placement? #69

Open marcmerlin opened 7 years ago

marcmerlin commented 7 years ago

When I booted my board, it showed 19C which was just about right. 15mn later once the board has run for a while, things warm up, and now it's showing 28C Yesterday, I put the board (running) in the freezer and got a temp of 5C. It seems that the board runs warm enough to affect the temp sensor.

marcmerlin commented 7 years ago

Ok, I did the freezer experiment again but this time I turned the board off. Then I took it out and turned it on right away. I got a temperature of -0.89C It feels too warm for a freezer, but confirm again that the board running is definitely raising the board temperature in a measureable way.

rdpowers commented 7 years ago

Ok, interesting. The normal usage would have cutouts and plane/fill removal around the BME280 to prevent this. I suspected that, given the area, the thermal mass of the PCB would be sufficient to counteract such heating. 5-10C is pretty significant, so this should be mitigated if possible in the next revision.

marcmerlin commented 7 years ago

run my iotuz code on your board and give it a shot, see what you get.