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

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