Raspberry fan control, Node-Red

Updated 2021-07-01 !

Do You want to have control over the Raspberry Pi(RPi) ? 

Functions

• CPU Temperature
• CPU Load %
• Free RAM %
• Disk Usage %
• Shutdown and Reboot buttons
• Fan PWM control via GPIO

Other NR posts on this site

Introduction

The above functions is implemented with Node-Red(NR) and I got inspiration from these sources

• Retrieving RPi data 
• PWM fan control
• Clock in the toolbar

At the bottom, in the dashboard, there are functions to 

• Shutdown
• Reboot
• Override the fan to 100% output

Fan control

The fan PWM control is realized with the circuit shown in the picture. The fan is connected to +12V DC since this is used in a boat application. You could use a 5V DC fan but then my recommendation is a separate supply, not using the RPi supply.

If the fan speed versus the CPU temperature don't match Your setup change the code in the "PWM Fan Control" node.

Measurements
The measures are made every 15 second and the CPU measure is "user space processes". A user space program is any process that doesn't belong to the kernel.

NR flow

Install the "node-red-dashboard" and "node-red-node-pi-gpio" node and then import the json file, from Github, to NR and check it out.

Remarks
2019-08-08 Refactored the Java code. OVERRIDE button code updated. Fan always on at least 20 %