ESP32 CNC shield for FluidNC and 3 external drivers (V1.3)

Note: This board has not yet been tested.

CNC board for ESP32 and FluidNC. Can be used with general GRBL senders, such as UGS. The board supports 3 external drivers, such as the 2160 Makerbot driver.

The connectors for these external drivers follow the PMinMo standard (http://www.massmind.org/techref/io/PMinMO.htm)

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.

All outputs are 5V, and able to power the opto-couplers that are generally found on stepper driver boards (which usually have a 270..330 Ohm series resistor).

An important feature of this board is that limit switches and other inputs are opto-isolated, thereby improving reliability.

Also ground for these inputs is isolated from the ESP32 ground.

Possible switches are HALL-Sensors, such as the LM393 3144 Hall Sensor Modules.

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

The board has holes at the same positions as a Raspberry-Pi board. In fact, the board was developed to replace my existing Raspberry Pi plus Protoneer boards,

which do not provide opto-isolation and can not easily be controlled via UGS.

My original idea was to develop a (cheap) board for THT, which needed to be assembled by myself. However, after I calculated the costs of assembly by JLCPCB,

I decided to go for partially assembled board. Connectors must still be assembled manually, however.Whenever possible, basic components were used, to lower costs.

The board needs to be powered via a separate 5 Volt external power supply.