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Anyone know any good DC powered or USB powered thermometers? (discuss.tchncs.de)
submitted 3 months ago by to c/homeassistant@lemmy.world
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I'm looking around for DC or USB powered thermometers but I can't seem to find any. Granted, the battery powered ones last many years, but I'm looking to keep my options open. Zigbee devices are preferable. Anyone know?

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[–] 4 points 3 months ago* (4 children)

I'm not sure why you'd NOT want a battery powered one, because as you say, the batteries last years, and a USB powered one would waste much more electricity over time, but I digress.

If you have any mini SoC boards or ESP32 devices laying around, you can get dirt cheap 2-pin external temp sensors. Works on anything with a GPIO pin out that supports simple I/O.

Anything you find that is Zigbee by nature will be battery powered, however, you might be able to find a device with a different purpose that happens to have temp sensors that export data you could monitor.

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  • [–] [S] 2 points 3 months ago (2 children)

    I do have a Pico sitting around. Maybe I can use it for a thermometer project.

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  • [–] 3 points 3 months ago* (1 child)

    Picos are very bad for battery applications. If you do end up doing this, make sure it is mains-powered like your original thought.

    Esp32s, MSP430s, and nRF chips have sleep currents down to around 5uA or less.

    Picos have sleep currents of 1-4mA. That is 1000x higher and the battery will only last for a few days instead of a few years.

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