Monitor raspberry pi's temperature and cool when needed. The project uses a small fan for the raspberry pi mounted on an acrylic case.
The raspberry pi's output pins can't be used to drive a small fan directly.
We can use an NPN mosfet to create a simple switch or driver for the fan.
I got some inspiration from this page.
The gate of the mosfet is connected through a 2.2k resistor to pin 1 (or GPIO18)
of the RPi.
The pin numbering can be a bit confusing on the RPi, but this page can provide some clarity: WiringPi pin numbering.
We're going to need the gpio command line tool, so we'll need to install
WiringPI
With this in place you can now:
# set pin 1 mode to output
gpio mode 1 out
# turn pin 1 ON
gpio write 1 1
This should effectively turn on your fan.
We can read the RPi's CPU temperature using:
/opt/vc/bin/vcgencmd measure_temp
The script at tempmon.sh ties things together. It reads the
temperature and when it's above $max it starts cooling, when it's below
$min it stops.
You can schedule the whole thing through cron to have it automated. Add a line similar to the one below to your crontab:
* * * * * /bin/bash -c "/home/pi/bin/tempmon.sh"
This monitors the temperature and manages the fan every minute.
- Acrylic casing and fan for raspberry pi (Aliexpress)
- Mosfet: 2N7000A
- 2.2k resistor