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README.md README: fix typo 2017-07-24 14:31:53 +02:00



This board allows you to connect an ATX power supply and a HD44780-compatible LCD screen to your Raspberry Pi (or others with compatible GPIO layout).

While it does have a 40pin GPIO connector, it will also work with older 26-pin variants of the Pi.

The board was created to provide a convenient interface for two Octoprint plugins: PSUControl and LCD-HD44780 (See links on bottom of this page).


The board itself offers a variety of features:

  • Powering the Pi using +5VSB (standby power)

  • Switching the PSU on and off using GPIO pin 12

    The GPIO pin can be connected to PS_ON directly, or via a transistor. This is choosable using the three-pin jumper switch.

    Alternatively, the PSU can be forced to be on, by using the 2-pin PS_ON jumper.

  • Providing a "is the PSU on"-detection by wiring GPIO pin 11 to the 3v3 rail of the PSU

  • Connecting a character LCD to the Pi

    LCD is wired as follows:

    Register Select
    Data 4
    Data 5
    Data 6
    Data 7

    Data 0-3 pins are not connected. Read/Write select has been wired to GND, so it's not possible to read data from the LCD screen. Contrast pin is connected to a potentiometer.

  • Allow connecting of two fans, one 5V, one 12V

  • Providing screw terminals for GND, +12V, +5VSB and +5V

  • Providing a USB outlet powered by +5VSB

Note: All pin numbers use BOARD numbering.


Prices are in Euro, and are based on my prototype production cost

Item Count Price Link
PCB 1 1.70 PCBway got me 10 boards for 17$
Fan connector 2 0.42 https://www.reichelt.de/?ARTICLE=185658
Pin header 3+2 wide 0.09 https://www.reichelt.de/?ARTICLE=119891
Potentiometer 1 0.38 https://www.reichelt.de/?ARTICLE=14951
LCD connector 1 0.52 https://www.reichelt.de/?ARTICLE=175351
Screw terminals 2 0.42 https://www.reichelt.de/?ARTICLE=170222
Jumper 1 0.03 https://www.reichelt.de/?ARTICLE=119944
USB connector 1 0.20 https://www.reichelt.de/?ARTICLE=22184
Transistor 1 0.09 https://www.reichelt.de/?ARTICLE=1999
Resistors 1+1+1 0.30 https://www.reichelt.de/?ARTICLE=1381
GPIO connector 1 0.11 https://de.aliexpress.com/…/32454935478.html
ATX connector 1 0.43 http://www.mouser.de/ProductDetail/TE-Connectivity/1-1775099-3/