Node: Temperature and Motion sensor don't work if batteries are below 3,5v

TheThingsNetwork / arduino-device-lib

Arduino Library for TTN Devices

MIT License

207 stars 96 forks source link

Node: Temperature and Motion sensor don't work if batteries are below 3,5v #127

Closed FokkeZB closed 7 years ago

FokkeZB commented 7 years ago

When the Node runs on battery, the temperature often returns as 0. I do have a temperature alert configured so the sensor shouldn't sleep. Or maybe it goes to sleep with the device? I increased the 250ms delay after waking up to 300ms but without result.

FokkeZB commented 7 years ago

This also happens:

[x] With the Tweetonig module library and TTN-Node_Demo sketch.
[x] When using a delay of 500ms before reading the sensor.
[x] When I strip out all deepsleep related code

FokkeZB commented 7 years ago

The motion sensor also doesn't seem to work (wake up the device) on batteries. When I have USB connected and shake, it sends a message. When I'm on batteries only it doesn't.

FokkeZB commented 7 years ago

For the record; the battery levels I had were around ~3350

FokkeZB commented 7 years ago

Yesterday I bought brand new batteries and with ~4446 the temperature and motion sensor do work. So the issue is that if the batteries drop below probably ~3500 these 2 sensors no longer work, while the button and other functions remain operational.

FokkeZB commented 7 years ago

@svenhaitjema will try to make the sensors work with less voltage. For temperature we could switch to the internal sensor which operates at lower voltage. This is not an alternative for motion.