Simulates an axis, drives RC Servo.
Want to use a servo in GRBL for the Z axis, but don't want to change your firmware?
This quick hack is designed as a plug-in replacement for a stepper driver such as the easydriver or Pololu driver. It reads the DIR and STEP signals and converts an internal step counter into PWM for an RC servo.
Great for use in existing hardware. No fundamental changes in firmware are needed.
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______
RESET-| |-+5V
HOME_Z-|ATTiny|-STEP
-|25/85 |-DIR
GND-|______|-Servo signal
Connect the parts to the respective pins. Set step direction to inverted in your Machine.
The fuses of your ATTiny should be programmed to the following values:
- lfuse: 0xe2
- hfuse: 0xdf
Using avrdude, you can set the fuses with the following command line (assuming an ATTiny25 connected via an Atmel AN910 compatible programmer):
avrdude -c avr910 -P /dev/ttyUSB0 -b115200 -pt25 -U lfuse:w:0xe2:m -U hfuse:w:0xdf:m
(adjust -c [programmer type] -P [COM port] -b [baud rate] to your setup)
Original code published 2014 by NilsRoe on Thingiverse (http://www.thingiverse.com/thing:224969)
Extended by Jan Reucker 2017.
Licensed under Creative Commons - Attribution - Non-Commercial (https://creativecommons.org/licenses/by-nc/3.0/legalcode)