Monitor App

The Pocket Pad does not have any spare pins for peripherals, however, it does have bluetooth which can be used to connect to external devices and sensors.

I had already made a Seeed Studio XIAO NRF52840 based environment monitoring station with BMP280 (Atmospheric Pressure) and SCD41 (CO2, Humidity, Temp) sensors. This includes readings from its sensors in the bluetooth advertising broadcast message. The Pocket Pad Monitor App receives these sensor advertisements and can then connect to a selected device using its BLE UART service to access trend data stored on the device. The picture below shows the sensor device and Pocket Pad accessing the record of the last six days atmospheric pressure readings.

The observant reader will notice some slight discrepancies in readings - these are caused by a loss of precision in the readings included in the Bluetooth advertisement messages - and some inconsistent treatment of rounding in my software :-(

Further details of the environment monitor can be found in the Github repository here.