The ADSB receiver OS image that I use provides several performance graphs including the CPU temperature. For receivers installed on a remote location that is maybe not enough to monitor what’s going on inside and outside the box. For that reason I decided to install additional temperature sensors in my ADSB receiver box. My choice was the the Dallas DS1820 1-wire temperature sensor. It’s easy to interface to an Raspberry Pi and the kernel comes already with drivers. Perfect for that purpose.
This upgrade is divided into two steps: 1. Connect the DS1820 to the Raspberry Pi and configure the kernel drivers – 2. Reconfiguring the collectd service and the shell script that is creating the performance graph so that the additional temperatures will be logged and plotted as well.
DS1820 sensor connection to Raspberry Pi 2/3
|DS1820 pin||Raspberry Pi I/O header pin|
|VDD||Pin 1 = 3.3V|
|DQ||Pin 7 = GPIO 4|
|GND||Pin 6 or 9 = GND|
One additional 4.7kOhm resistor is required between 3.3V and signal DQ as shown in schematic.
Enable 1-wire kernel driver
The 1-wire kernel driver will be enabled in
/boot/config.txt by adding the following lines at the end:
#Enable One-Wire bus
Since we use an external pull-up resistor the GPIO will not use its internal.
After reboot the sensors can be checked like this:
$ cat /sys/bus/w1/devices/10-000800507da4/w1_slave
1e 00 4b 46 ff ff 0c 10 fc : crc=fc YES 1e 00 4b 46 ff ff 0c 10 fc t=15000
$ cat /sys/bus/w1/devices/10-0008008d2583/w1_slave
04 00 4b 46 ff ff 09 10 fb : crc=fb YES 04 00 4b 46 ff ff 09 10 fb t=2187
The folder names are different for any connected sensor as they depend on the sensor serial number. So use
$ ls /sys/bus/w1/devices/ to list available folders.
Temperature is given at the end of second line in 1/1000th degree Celsius, here 15000 = 15.000 degree Celsius and 2187 = 2.187 degree Celsius.