DIY GRBL 0.9+ board for Arduino Nano

I made a small laser cutter recently. This should be driven with an arduino nano. There are on eBay and other shops a "CNC Shield Version 4.0 Board". Hopefully I ordered several of these boards right away. But then came the bad surprise. All of these boards had errors and wrong connections. Without major alterations they were not up and running. That's why I've developed my own board for the Arduino Nano.

The designation of the connectors is grbl 0.9+ compatible. My board contains some more features. It is a buck regulator (MP1589) included, which ensures the power supply up to 24V input voltage. Thus, the stepper drivers can also be operated with this higher voltage, which may be useful in some circumstances. The diameter of the conductor tracks for the stepper drivers is sufficiently large, so that even higher currents can be used. In addition, the strong buck regulator also enables the supply of additional 5V consumers, such as sensors. The buck regulator and therefore the 5V technology is protected against reverse polarity of the input voltage by a power MOSFET.

You can see my machine powered by this board in this video.

There is another function. The enable signal of the stepper driver is used to control a fan. A fan for cooling the stepper driver can be connected to a small pin header. This fan must be a 5V fan or a fan suitable for the input voltage. This only runs if the stepper driver is active.

This project also includes a driving circuit for a laser. Here, too, I made bad experiences with the original circuits supplied and therefore developed my own circuit. Because lasers are very expensive and dangerous and do not forgive mistakes, only the experienced electronics technician should make a replica!

The driver circuit is a constant current source that can operate in PWM mode thanks to the high-speed optocoupler with up to 10 kHz. This circuit is suitable for laser diodes with currents up to 4.5 amperes. This laser driver purposely contains a slow dual OPA (LM358) because it provides a relatively clean output signal and it is frequency compensated for common mode. In addition, a time-delayed shutdown for the fan of the laser is realized with the second internal OPA from the LM358. The cooling of the laser starts when an input signal occurs and runs for another 30 seconds after the laser is switched off. 

However, what is additionally required is a good buck regulator, which provides the voltage required by the laser with sufficient power.

 

The output voltage of the buck regulators must be set to the maximum permissible voltage of the laser diode. This protects the diode and prevents overheating of the power MOSFET.

My KiCAD project files can be downloaded from my Google Drive

GRBL_V5.1 Board.zip
Bytes: 325107
MD5: 91B9ADBFE746B63C90AB36BA9C61E63C
SHA256: 2EAED850FB707BC1446D05051EEA5079F24879DAF73AB74D940CEB199D16B06F

Laserdriver.zip
Bytes: 249616
MD5: 2D7AEB7AF62058AF386E62074C359C56
SHA256: B427C313B893E182B4026F11F3932480043F2D06B0BB0B0D029E95F10FC63AC4

There is another archive in the ZIP files. This can be uploaded directly to a board manufacturer (I use Seedstudio or JLCPCB) to order professional PCBs in your desired color.

My project is free for private use. It is aimed at experienced people. I take no guarantee! Duplication is at your own risk and responsibility!

You are welcome to customize or modify my project and publish it. However, you always have to refer to the origin!