Jeff Epler's blog2021-08-18T19:03:43ZPhotos, electronics, cnc, and moreJeff Eplerjepler@unpythonic.netUsing Adafruit Macropad as LinuxCNC Control Pendant2021-08-18T19:03:43Z2021-08-18T19:03:43Zhttps://gamma.unpythonic.net/01629313423
<b>Update, 2021-09-25</b>: For compatibility with CircuitPython 7.0.0
<p><img src="https://media.unpythonic.net/emergent-files/01629313423/PXL_20210818_191419458.jpg">
<p><br>CircuitPython recently gained the power to have custom USB descriptors.
With these, we can define a USB HID device that will work with LinuxCNC's
hal_input.
<p>For instance, the <a href="https://www.adafruit.com/product/5128">Adafruit
Macropad</a> has a (very coarse, just 20 detents/revolution) encoder, 12 keyswitch
positions, and an OLED screen.
<p>The two pieces of software below, when placed in the CIRCUITPY drive as boot.py
and code.py configure it for use with hal_input, using a halcmd line similar to
<tt>loadusr -W hal_input Macropad</tt>. I haven't actually done the
work of hooking it all the way up to Touchy yet, but it causes all the buttons
& the encoder to appear in <tt>halcmd show pin</tt>.
<p>This is just the device I picked first; there's nothing to prevent you from
hooking up more exotic things like voltage/temperature monitors through added
CircuitPython code. Addition of output reports for status indicators is left
for the motivated reader.