This project is a small automatic cooling system for home theater rack. It supports 2 temperature sensors for different zones in the rack and 2 12V PWM fans (standard for PC case cooling). There is a power switch connector for a switch mounted on the casing (will be designed and 3D printed later). A reset button is provided mostly for reprogramming purpose. There are 4 buttons for setting up temperatures for fan start (minimum PWM duty cycle can be set) and maximum rpm to fit the user needs. LCD shows current temperatures and rpm for both zones. The backlight is off all the time except when settings are being changed.

The modules used are shown in the following photos:

The LCD is standard HD44780 character display with 2 rows and 16 characters per row. The interface converter for the LCD used I2C input which reduces microcontroller pin usage to only 2 (plus 1 more to turn on the backlight). I bought it off eBay and it is easy to find. Arduino Pro Micro is a custom made mix between Arduino Leonardo and Arduino Micro Pro. I bought mine from eBay, but it is also available at Spark Fun.

Currently there is no firmware available for this project. I will start working on it when I have the hardware assembled.

Other notes: The fan connectors are not the ones found on the PC mother boards. I selected securely locking connectors to ensure good connection. Since I need longer cables for the fans than the ones they are sold with, I have to make them myself anyway, so I decided to use better connectors. More info on this project you will be able to find on my hobby website. For example firmware when I develop it.

Change Log Rev3 - 03.2017

• Tact switches pinout issue fixed. With previous design wrong pins were used so all switches would be always closed
• PCB title print typo fixed (it was saying THETER instead of THEATER) :)

Rev2 - 03.2017

• Added custom schematic parts and PCB footprints
• Schematic rearranged and cleaned up
• PCB design finished

Rev1 - 02.2017

• Project created
• Schematic created
• PCB created