I like monitoring/graphing data, so I picked up this $10 TEMPer v1 USB thermometer from China for a DIY weather station. It is currently measuring the temperature outside my window.
The device is detected out of the box in Ubuntu Linux:
[89921.774619] input: RDing TEMPer1V1.4 as /devices/pci0000:00/0000:00:12.2/usb1/1-1/1-1.1/1-1.1:1.0/input/input18
[89921.775505] hid-generic 0003:0C45:7401.0009: input,hidraw0: USB HID v1.10 Keyboard [RDing TEMPer1V1.4] on usb-0000:00:12.2-1.1/input0
[89921.784326] hid-generic 0003:0C45:7401.000A: hiddev0,hidraw1: USB HID v1.10 Device [RDing TEMPer1V1.4] on usb-0000:00:12.2-1.1/input1
It still needs software to actually read data from the device. A suitable driver can be found here: https://github.com/petervojtek/usb-thermometer
git clone https://github.com/petervojtek/usb-thermometer.git cd usb-thermometer/ make
Run as ./pcsensor
I needed something that would output in Collectd format, so I made some modifications, adding calibration and Kelvin output just for fun:
New options are:
-k output only in Kelvin
-o offset (in Celsius) added to all temperature readings
-g[n] output for data collection/graphing tools (0=mrtg, 1=collectd)
offset is a floating point number added to all readings for calibration, it can be negative.
In collectd.conf, I run like this:
Exec incognito "/usr/bin/pcsensor" "-g1" "-l10" "-o0.5"
Probe is stated by vendor to be waterproof. I added some heat shrink just to make sure.
As for accuracy, it seems acceptable. Comparing to UK Met Office readings it is usually +/- 1 C, which is good enough for me.