The ExtFet Board adds two outputs to the Prusa Mk3 Einsy board which can be controlled by OctoPrint or in GCode. These outputs can be used e.g. for a Light Bar, IKEA Ledberg Spots or any other things you want to supply with 24V.

Please keep in mind that the Prusa PSU can supply up to 240W (10A) in total for the printer and all attached devices.

The board is supplied as a kit, with the optional addon of header pins and/or JST cables. If you supply your own header pins, you will need to use 18mm long pin heades. The standard 11mm pin headers commonly used in electronics will not make a connection to the Einsy board.

Options

PCB only

One board, with SMD components soldered. Long pin headers need to be bought seperately. See "Soldering the GPIO pins" from PrusaPrinters for the length of pins needed. Please note, that the ExFet is designed so that all pins can be soldered to the board.

Added headers

PCB with 2x 7-pin 18mm headers which need to be soldered by you.

Added headers and cables

PCB with 2x 7-pin 18mm headers and two sets of cables which need to be soldered by you.

How does it work?

There is no need for a modified firmware, as the stock firmware can address unused pins without any problems. The command M42 Pxx Syyy controls any unused pins.

Commands

• Top connector on: M42 P19 S255
• Top connector off: M42 P19 S0
• Bottom connector on: M42 P73 S255
• Bottom connector off: M42 P73 S0

What makes it special?

It integrates into the stock Raspberry Pi Zero port of the Einsy mainboard, so there is no permanent change done to the printer's mainboard.