This provides the core sensor functionality (other than acoustic and visual) for WildlifeSystems nodes. A default sensing device, onboard is provided which provides useful diagnostic information about the Raspberry Pi.
wget -O - https://raw.githubusercontent.com/Wildlife-Systems/sensor-control/main/install | sudo bash
To read a sensor use the sr script sr <device> <sensor>, e.g. to read the onboard CPU temperature run:
sr onboard onboard_cpu
sr provides an array of JSON ojects that each describe the sensor and measurement.
| key | value |
|---|---|
| sensor | Short name of the sensor (no whitespace) |
| measures | The property being measured (e.g. temperature) |
| value | The value currently measured by the sensor |
| unit | The unit of measurement of value |
| node_id | The serial number of the aao node |
| sensor_id | Serial number of sensor (if available) |
| timestamp | Timestamp of when the sensor was read |
| config | (Optional) Additional configuration details about the sensor. May be JSON array. |
New sensing devices should be added a seperate scripts/programs that take the prototype JSON response generate by sc-prototype and populate the values sensor, measures, value, unit and, where appropriate, config. The modified JSON should then be printed to stdout.
The fields node_id and timestamp are populated by the sensor read command, sr.
The sensor-onboard script installed with this package provides a reference implementation in bash using the jq command to process JSON.
There are no restrictons on the scripting/programming language(s) that may be used, however it should be kept in mind that the scripts will likely be running on connected, autonomous nodes. For this reason it is reccomeneded that minimising the installation of additional packages, and the number of scripting environments overall, should be priorities (there is a reason that sensor-onboard is written in bash).
- Development of this script was done as part of the Urban Nature Project at the Natural History Museum, London.