These USB sensors are available pretty cheaply from PiHut and Amazon and are great for monitoring the temperature remotely (where you have a Pi).
Install the necessary prerequisites:
sudo apt install libhidapi-dev/stable cmake bc
There is a GitHub repository by Frode Austvik:
This project is a C implementation of a library and program to read all the various types of TEMPer thermometer and hygrometer USB devices, as produced by RDing Technology and sold under the name PCsensor.
Download the software
git clone https://github.com/edorfaus/TEMPered
And build it and install:
cd TEMPered
cmake .
make
sudo cp utils/hid-query /usr/bin
Create a simple script to query the device and display the temperature.
!/bin/bash
OUTLINE=/usr/bin/hid-query /dev/hidraw1 0x01 0x80 0x33 0x01 0x00 0x00 0x00 0x00 | grep -A1 ^Response|tail -1
OUTNUM=echo $OUTLINE|sed -e 's/^[^0-9a-f]*[0-9a-f][0-9a-f] [0-9a-f][0-9a-f] \([0-9a-f][0-9a-f]\) \([0-9a-f][0-9a-f]\) .*$/0x\1\2/'
HEX4=${OUTNUM:2:4}
DVAL=$(( 16#$HEX4 ))
CTEMP=$(bc <<< "scale=2; $DVAL/100")
echo date $CTEMP
This works perfectly but it must be executed with sudo, or by first
running chmod 666 /dev/hidraw. This can be automated by creating
/etc/udev/rules.d/99-hidraw.rules with the content below which creates
the /dev node with the appropriate permissions.
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0666", GROUP="root"
I’ve added a cron job (crontab -e) to record the temperature every 5
minutes:
0,5,10,15,20,25,30,35,40,45,50,55 * * * * /home/pi/temp.sh >> /home/pi/temperature.txt