E-ink weather display, round two
The first version of this display lived on the hallway shelf for most of the summer. It looked nice, but it needed a charge every four or five days, which is about three weeks too often for something that only changes twice an hour.
What was wrong
The old board never really went to sleep. The radio stayed half awake between updates and the voltage regulator wasted a few milliamps all the time. I measured it with the multimeter in series and got a little over 4 mA while “sleeping”.
What changed
- New board with a proper deep sleep mode and an external low-power regulator.
- Updates every 30 minutes instead of every 10. Nobody needs the temperature that often.
- The panel is only refreshed when the forecast actually changes.
| Round one | Round two | |
|---|---|---|
| Sleep current | ~4.2 mA | ~45 µA |
| Battery life | 4–5 days | ~5 weeks |
Next
A small wooden frame, so it stops looking like a science project. That is a job for a rainy Saturday.
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