Using Active Low Stepper Drivers.
Typical stepper drivers expose both the positive and negative inputs of the opto-couplers but some older drivers do not. They often require a "pull down" interface where the inputs are +V and the step/direction/enable inputs which are pulled to 0V to trigger. This blog describes how you can use these drivers with Brookwood Design's controller boards such as the T41U5XBB, RP23CNC or PicoCNC. Study the diagram below. It shows the connections for the A Axis. Duplicate this for
EMI - Science, Voodoo or DooDoo?
A way forward to deal with EMI. I've been building CNC machines for more than 20 years and while the technology has changed a lot, one...
So, what's wrong with Grbl on the Arduino?
Arduino Uno vs Pico Smackdown? In a word, nothing is wrong with the Uno. But, there is nothing wrong with the original IBM PC. Though, I wouldn't want to use it either. Grbl running on an Arduino Uno was an amazing feat. I am in awe of the original Grbl team that was able to shoe horn a complete CNC control system into a pokey little 8-bit microcontroller and make it work pretty well. Sure there were some trade offs - step rate for one and not all features could be include
Which breakout board should I use?
OR Having 2 different boards has lead to a number of people asking which one they should use. Hopefully I can help you work through this...
A Peek at the PicoCNC
I've been designing a new CNC controller breakout board based on the Raspberry Pi Pico. We are calling it the PicoCNC. This is a very...
Using Relays with grblHAL and the T41U5XBB or PicoCNC
I regularly get questions about using relays. So, this blog entry's goal is to make it easier to understand. Relays are often used in CNC...
Logic Relays on the screw terminals?
The screw terminals on the breakout board are used to drive relay coils. As such, they are set up as an open collector output and used...
Using the grblHAL Web Builder
Terje at io-Engineering has created a fantastic builder for grblHAL. This allows you to build custom firmware files with no software...
Making sense of Feeds and Speeds
When I started out, one of the more confusing aspects of CNC machines was the concept of Feeds and Speeds. It seemed like a lot of math...
Networking the T41U5XBB and RP23CNC
Ethernet is a great feature of the T41U5XBB and RP23CNC. It is very easy to set up and use. Because the Ethernet interface uses transformers, the PCB is galvanically isolated from the Ethernet cable and is not a conduit for EMI. USB, on the other hand, is not isolated and EMI can be an issue. Also, Ethernet IP is a self correcting protocol. Any error packets will be rejected and resent. This procedure will allow you to connect to a router that dynamically assigns an IP addre
