The-JC / FanCo

Fan controller for a wind channel

FanCo

FanCo is an advanced wind tunnel fan controller. Monitoring and regulating up to 120 fans individually with its custom UI or the API. The UI navigation is simple and intuitive utilizing just a rotary encoder. FanCo is also capable of logging fan speeds over a longer period for later analyzation.

FanCo is made up of two fundamental components. The master managing the UI and logging. And second, the slave, measuring actual speeds and compensate fluctuations in speed. Each Slave is capable of regulating up to 4 fans. Further slaves can be connected via cables to expand the maximum amounts of fans and also remove the number of control cables needed.

Table of contents

• Requirements
• Installation
• Usage
• Principle of operation
• Troubleshooting
• ToDo

Requirements

• RaspberryPi Zero (W) or 1 (2 or later only works with custom build)
• Slave PCB manufactured and soldered from your favorite Chinese manufacturer (see Parts List).
• USBasp programmer (An Arduino can be used as a programmer).
• Any HDMI compatible display (we used a small 5" HDMI display)
• A rotary encoder as an input
• One or more 4-pin fans
• A 5V power supply to provide power to the Raspberry Pi and the Display

Installation

I. RaspberryPi

1. Download the latest Raspbian Version from https://www.raspberrypi.org/downloads/ and flash it to the SD card.
2. Insert SD card into the pi. Start it check if it boots.
3. Run sudo apt-get update & upgrade to update all packages.
4. Make sure you've downloaded and installed pigpiod from http://abyz.me.uk/rpi/pigpio/download.html.
5. Download the latest version of FanCoUI from
   https://github.com/The-JC/Rflw/releases/latest

   You can use wget to directly download the binary to the RaspberryPi.

6. To run the FanCo UI run ./fanco in the installation directory.
7. When using an 800x480 display change or add the following lines in
   /boot/config.txt

   hdmi_group=2
   hdmi_mode=87
   hdmi_cvt=800 480 60 0 0 0
   

8. To autostart FanCoUI at boot. Add the following lines to your rc.local before the exit 0 line. sudo nano /etc/rc.local

   pigpiod
   PATH_TO_FANCO/fanco
   

II. Slave

Requirments
You will need avrdude for flashing the program to the Slaves. Also you will need avr-gcc installed to compile the program. Further the build system CMake and make is required. You can install both on Ubuntu or Debian by running sudo apt-get install avrdude gcc-avr

1. Connect the programmer and the slave, like shown in the following picture
2. Connect the programmer to the computer.
3. Change your current directory to cd programs/slave/FanRegulator_v01
4. Change the slave address line #define ADDRESS 0xXX in include/config.h starting with 0x04
5. Configure the build by running cmake -B build . in the root directory of FanRegulator_v01
6. Go to the build directory by running cd build
7. Run the following command to compile the program and flash it to the microcontroller: make flash
8. Repeat the previous steps for every other microcontroller only changing the I2C address.

NOTE: Currently only a USBasp programmer is the supported. We´re are working on supporting other programmer types like ArduinoISP. If you can't wait, you could also flash the binaries manualy using avrdude.

III. Cabling

• Connect the rotary encoder, slave(s) and the display to the Raspberry Pi following the below scheme.

Usage

1. Run sudo pigpiod
2. Start program by running ./fanco

Principle of operation

The slave counts pulses(n) received on the tacho pin in a set interval(dt). By calculating f=n/dt you`ll get the frequency(f) of the input signal. Further multiplication x60 converts the frequency from 1/t in s to min which equals RPMs (revolutions per minute). Previously calculated speed is used for fine-tuning the fans set signal, to achieve a steady and constant speed at the desired speed.
Further, the acquired data is requested by the master (RaspberyPi) every second. For logging, displaying and synchronization purposes.
Firstly it´s averaged out to compensate for measurement and transmission errors. It later gets stored for logging and plotting purposes.

Troubleshooting

Rotary Encoder is not recognized

• Check if cables are connected correctly
• Make sure you have pull-up resistors on all 3 data lines

FanCoUI shows invalid or random data

• Make sure all slaves are powered up
• Check the data bus for wiring errors
• Check if all slaves are recognized by running i2cdetect -y 1
• Try running i2cdump -y -r 0-2 1 0x04 c
  • Reading devices fails -> restart all slaves & try updating slaves
  • Reads X X X as byte-value -> restart all slaves
  • Reads some byte-value -> all should be good try updating FanCoUI to the latest version.

ToDo

• Interval programming
• Extended logs
• Remote control API
• init.d start script
• Enclosure
• Flow dependent speed control