GRBL CNC board. The processor is an Arduino Nano. Can be used with general GRBL senders, as well as Estlcam.

The board supports five drivers, and is specifically designed for MPCNC.

Can be used with generic CNC drivers, such as the A4988, DRV8825 and TMC2209.

An external relay board with 4 relays may be connected, to switch, for example, the spindle on or off.

A possible relay board is the HW-316 4 relay board. Connections fit with that board.

An important improvement compared to the traditional CNC-Shields is that limit switches are opto-isolated,

thereby improving reliability. Preferred switches are HALL-Sensors, such as the LM393 3144 Hall Sensor Modules.

Normal opened (NO) limit switches should also work, and connected to pin 1 (marked -) and 2 (middle) of each connector.

There are two seperate (DC) power inputs. One for the motors; voltage may be anywhere between 12-36V.

The other is for the Arduino Nano (as well as opto-couplers and relay drivers). Best is to use a separate 5V power supply.

It is possible to use an external LM2596 converter to convert the 5V power from the motor SPS.

If the power jumper is open, the Arduino Nano will be powered via the USB connector from the computer.

If the power jumper is closed, the Arduino Nano will be powered from the 5V connector.