Arduino firmware to monitor voltages and log their values to a serial port.
Should be widely compatible with hardware supporting Arduino.
Set up for use with PlatformIO; includes a VSCode workspace.
A build target for the ESP32-C3 DevKit M-1 board is included. This mainly
required some customizations to the ESP-IDF sdkconfig, to prevent logging
other stuff to the serial port.
The key settings are currently in the source code, in main.cpp, in the Feature configuration section.
It would be cool to replace those with a console interface via serial input, that would save the last-used settings to non-volatile storage.
Defaults are currently to log the voltage on the Arduino pin A1 every 4 seconds,
and to go to "warning" mode below 3.0 V and to "error" mode below 2.7 V.
Plug the programmed board into USB, or otherwise power it and connect it to a serial port.
Connect jumpers from the board's GND and A1 pins to the device-under-test's GND and the pin you want to log.
Monitor the serial output via a console program.
You can use my other project Retrover to monitor the serial output interleaved with the log from another board under development.
I found this particularly useful for diagnosing problems caused by brownouts on a power supply. Retrover's output merges Saggydog's with the output of the board under test, so when a brownout caused the chip to reboot, the Retrover log looked like this:
2023-08-07 16:42:53.409611 > ~S=4 ?=1 ?*
2023-08-07 16:42:53.741868 < 3.30 V
2023-08-07 16:42:54.414825 > ~S=4 ?=1 ?*
2023-08-07 16:42:54.798462 < 2.98 V ??
2023-08-07 16:42:55.890083 < 2.79 V ??
2023-08-07 16:42:57.106462 > CB 7.9.2
2023-08-07 16:42:57.106462 > ~S=2 ?=1 ?P ?*
2023-08-07 16:42:57.108566
== EVENT FOUND ==
2023-08-07 16:42:57.383441 > [P.]
2023-08-07 16:42:58.101074 > ~S=2 ?=1 ?*
2023-08-07 16:42:59.191474 > ~S=2 ?=1 ?*
2023-08-07 16:42:59.797474 < 3.30 V
Retrover labels the Saggydog output with < and the test board's output with >.
Normal output at nominal supply voltage (3.3 V) is then followed by dropping
voltage, flagged with ?? and accompanied by a faster reporting rate,
followed in turn by the message CB 7.9.2 which is the version number of the
board under test, output when the board reboots. After rebooting, supply
voltage returns to 3.30 V.