Steven Mackaay's stuff

NCComm – An RS232 device for CNC communication

So, I wanted to try my hand at making a communication device between a standalone device and the CNC, something I wanted. I achieved that. I wanted it made out of the most common parts an average person can easily buy off Aliexpress. You can buy one for like 200 bucks but it was fun to make nonetheless. Things you need for this build:

• Arduino Mega 2560 or 1280 (I used this because it had enough IO, you could use a nano or a standard arduino but you’d wanna use a different keypad)
• A membrane keypad (This one is a 4×5 keypad, so 9 IO are needed)
• An SD card module that accepts 5v. (I used the large style, it is more hardy in an industrial environment.)
• A 2004 LCD module with an I2C backpack (You can use a standard LCD without a backpack but you’ll want to change the way the output is used, I made a wrapper for that.)
• An RS232 module. (This one should be with RTS and CTS, most CNC’s I know of need handshaking or just a CTS signal unless you tie the RTS CTS lines together on the cable)
• Not necessary but I used a hat for the 2560 just to simplify the connections to the board to use standard headers.

Simple, straightforward. Here is the code I have thus far. It’s not too solid and handshaking isn;t working perfect but it works thus far.

Here: https://www.smackaay.com/wp-content/uploads/2025/04/NCComm.zip

Enjoy