I like monitoring/graphing data, so I picked up this $10 TEMPer v1 [amazon text=USB thermometer&template=amazon search] 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: https://github.com/standard-error/usb-thermometer

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: `

`

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.