This project uses an HR-SR04 sensor to report upon distance.
In this case the sensor is mounted below my monitor, with the intention that it can decide if somebody is present or not based upon measuring the distance to the nearest object.
If I'm sat in front of the desk I will be measured at 70-90cm away, if not the reading will refer to the wall behind me ~2m away.
The distance information will be published to a MQQ / Mosquitto server on the
topic distance. Additionally the board will dump all its meta-info
to the topic meta on startup.
The meta-information includes:
- Hostname
- IP Address
- MAC Address
- etc.
You'll need to change the IP address of the MQQ server if you wish to deploy this yourself.
The sensor is wired to pins D2, and D3, which you can see documented in the script itself.
There is a simple Perl script included in Handler/ which will receive
messages and trigger a "present" and "away" function, based upon the
reported-distance. See the script for details.