# voltage_monitoring

Written for Ron P. using an Arduino UNO

Modus operandi:
- Read the analog inputs every READ_INTERVAL_MINUTES, NUMBER_OF_SAMPLES_PER_AVERAGE times TIME_BETWEEN_SAMPLES_MS apart.
- Calculate the average of these readings and write the results to a CSV file on the SD card.

Nota bene:
The CSV entries are indexed with a "time" which is the number of milliseconds the Arduino has been powered on. This isn't ideal but it avoids having to add a Real Time Clock hardware module and backup battery.

Since the maximum input voltage on the Arduino ADC inputs is 5 Volts, a resistive voltage divier is required to scale down the desired voltage. The SCALING array is provided as a convenience to scale the output back up to the real-world level. The scale factor can be set on a per-input basis.

Unexpected Arduino reboots are to be expected. File I/O is therefore kept to a minimum and the buffer is flushed immediatley to prevent data loss. The output file is statically set and is only ever opened in APPEND mode, so the contents are never over-written. A downside to this approach is the need to sanitize the CSV file before it's imported into a plotter.