2020-08-18 (Tu) InCompass

I needed to determine the battery cutoff voltage so I could alert users when their battery was low. Before, I guessed, and that resulted in a dead battery. I changed the battery checking loop structure so it would not stop the rest of the code, and after charging, it could exit. I thought the voltage coming off the battery was too night, but I confirmed it with a multimeter.

My plan was to connect the board to a computer and let it run until the battery died. While it ran, it would send serial messages with the battery voltage level so whatever the last reading was, would be my minimum usable voltage. Unfortunately, after five hours, the battery level was the same, so my serial adapter was powering the device.

Next, I desoldered the battery and replaced it with an adjustable regulated power supply. This time, I planned to turn down the voltage until the board failed. Then, I could measure that voltage and use that as a starting point for my threshold. The power supply I had handy would only step voltage up, so I could not get below 5V, and the test was fruitless.
5V minimum power supply

GitHub repo for Cardinal, aka InCompass

The rest of the posts for this project have been arranged by date.


Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7

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2020-08-17

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