AR844 Sound Meter MQTT Publisher
I’ve embraced MQTT as my preferred method of gathering device information.
The latest project was to interface to my AR844 Sound Meter. The meter has a USB interface and comes with some Windows XP software to read the data. I managed to get it to run once on my Windows 10 laptop, but the software died and locked up the meter after about an hour. I was never able to get it to the interface software run again on Windows 10, so that stopped me from using Wireshark to spy on the USB traffic – luckily, someone else has done the hard work decoding the communications.
So thanks to Brainworks.it for publishing the reverse engineering http://www.brainworks.it/rpi-environmental-monitoring/reveng-the-usb-data
Unfortunately, I then had problems getting the older python code to work (USB problems), so I wrote a simple C version. This uses libusb and libmosquitto to perform the usb and MQTT communications. This is run on a RaspberryPI Zero W, so it is always on measuring sound.
In the future I’ll start doing something with the gathered data.
Project is here – Github MQTT_AR844 Project