SMART FAN for Raspberry Pi cooling: a must for all mission critical installations
Raspberry Pi four was welcomed by the Pi enthusiasts for the increased processing power. However, this came at a price. The Pi 4 can draw up to 3 Amps, which means it has to dissipate 15 watts of power. Raspberry Pi cooling is a must.
From the simplest passive heat sink, through elaborate fan blowers and even to an exotic water-cooled idea, many options are available.
While lacking no imagination, all have a common denominator: it is almost impossible to plug an add on card into the GPIO expansion header.
THE SMART FAN
The most elegant, compact and inexpensive cooling solution for your Raspberry Pi.
The Smart Fan has the form factor of the Raspberry Pi HAT. Its own tinny 32 bit processor receives commands from Raspberry Pi through the I2C interface. A step-up power supply converts the 5 Volts provided by Raspberry Pi to 12 Volts, ensuring precise speed control. Using pulse width modulation, it powers the fan just enough to maintain a constant temperature of the Raspberry Pi processor.
The Smart Fan preserves all the GPIO pins, allowing any number of cards to be stacked on top of Raspberry Pi. If another add-on card has to dissipate power, a secondary Smart Fan can be added to the stack.
The Smart Fan can be controlled from any program using simple command line or Python functions. A Node Red interface let’s you set and monitor the temperature from the browser. The software can maintain the temperature history in a log file which can be plotted in Excel.
Node-Red picture coming here
Together with multiple add-on cards, the Smart Fan can be installed on the DIN-Rail, for sturdy industrial applications.
The Smart Fan has a LED controlled by the local processor. At power up, the processor powers up the fan for 1 second, so the user can make sure the system is functional. The on board LED shows the status of the fan. When the fan is off, the LED blinks 1 time per second. When the fan is turned on, the LED blinks between 2 to 10 times per second, proportional with the speed of the fan.
WHAT’S IN YOUR KIT
Since the fan can be installed either on the top or on the bottom of the card, it comes unassembled. If you plan to use the Smart Fan to cool the Raspberry Pi, we recommend to install it on the bottom. To cool any other add-on card, install it on the top. All mounting hardware for installing the fan on the card, and the card on Raspberry Pi, is included.
Smart Fan Card
40x40x10mm Fan with mounting screws
QUICK START-UP GUIDE
- Plug your SMART-FAN card on top of your Raspberry Pi and power up the system.
- Enable I2C communication on Raspberry Pi using raspi-config.
- Install the smart-fan software from github.com:
~$ git clone https://github.com/SequentMicrosystems/
~$ cd /home/pi/smart-fan
~/wdt-rpi$ sudo make install
The program will respond with a list of available commands.
CONTROLLING THE FAN SPEED
Since the Smart Fan is slave to the I2C interface, Raspberry Pi must tell it what to do. Command line and Python functions are available to control the fan speed. Raspberry Pi needs to monitor the processor temperature and control the fan speed accordingly. A PID loop sample program can be downloaded from GitHub. In case of malfunction, if the temperature exceeds a safe limit, Raspberry Pi must shut itself off to prevent burnout.