N7JTI CNC Pendant Build



  • As part of my CNC Build I also built one of the CNC Pendants. It seems like a nice design overall. However, I did make a few changes. I love that evertying is open-source so I can tinker and share. But first, some pictures:

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    20201123_181653 (2).jpg

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    The build is nearly the same as the official link, but I substituted out the microcontroller for a Black Pill. This is an STM32F411 chip. There is full Arduino support (and micro-python, and native C/C++ support as well).

    I had to make some minor changes to the firmware. The changes fell into two categories. The first was updating all the inputs to match my build here. The 2nd was to fix the definition of a single class to remove the word "override" as it somehow prevented the build when using the stmduino libraries. My fork of the code-base can be found on my github here:

    The readme has the updated wiring and all the working changes to the code for the firmware. There are still lots of open IO ports on the board. I may even add some additional buttons to the pendant later.

    As for the BOM, I got he parts from ali-epxress:

    The choice of microcontroller simplified the design as the STM32 controller is a 3v3 Device but its inputs are 5v tolerant. The board takes the 5v in for power and tolerates the 5v GPIO inputs, but it sends out its own logic levels for the serial port at 3v3. So no need for the voltage divider on the output back to the board. And as you can see, even with the programming header installed, the board fits very nicely in the pendant.

    I'm still in the middle of my build so I haven't had it connected to the CNC machine yet. but I was able to do all of my testing by hooking up the output to a USB to serial converter: https://www.adafruit.com/product/3309. And I'd highly recommend using this method for testing as you can read the g-code commands directly in your serial terminal. Very handy!



  • I got the parts in to connect the pendant, and I got the box mounted. I also got the endstops programed to halt if the machine hits the endstops, but it stills homes. The parts on the deck are to mill the dust shoe.

    The updates for the config have been uploaded to github: https://github.com/n7jti/duet3-avid-cnc

    plendant.jpg


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