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Adding a rotation axis (bottle cutter)
Added by peteruithoven over 10 years ago
Thanks to the hackability of LaOS, Fablab Amersfoort now has a Rotation axis.
It can be switched in or out relatively easy because we uses the Z-axis outputs for this and altered the firmware to use these pins for the Y axis. Basically we make the firmware think it's moving the Y axis but it's actually moving the Z axis.
How¶
Firmware¶
To make the firmware think it was controlling the Y axis we changed the pins in /laser/LaosMotion/LaosMotion.cpp:
// Inputs; DigitalIn xhome(p8); // p8 DigitalIn yhome(p16); // p17 DigitalIn zmin(p16); // p15 DigitalIn zmax(p16); // p16 // motors DigitalOut enable(p7); DigitalOut xdir(p23); DigitalOut xstep(p24); DigitalOut ydir(p27); // p25 DigitalOut ystep(p28); // p26 DigitalOut zdir(p29); // p27 DigitalOut zstep(p30); // p28 DigitalOut estep(p29); // NOK: CAN, (TODO) DigitalOut edir(p30); // NOK: CAN, (TODO)
See http://redmine.laoslaser.org/projects/laos/wiki/CompilingFirmware on how to compile the firmware yourself.
Electronics¶
![](/attachments/download/321/IMG_0236_2.png)
Our current Morntech lasercutter had it's own motor stepper drivers (we didn't use pololu's). These external stepperdrivers got 5v through J15 en J21 (which connected the + output to the VPP. VPP got his 5v trough the VMOT input. Now this needed to change because the pololu (or our rotation motor) requires 24v.
So we:
- disconnected the J15 and J21 jumpers,
- and connected 2 pins on the pololu footprint to get 3.3v to the external X & Y drivers; pin 10 (VDD) to pin 14.
- We removed the MBED (for it's own safety).
- Wired the 24v of our power supply to the VMOT input.
- Connected the 24v ground to the 5v ground on our power supply.
- We checked that there wasn't going 24v to any of the MBED pins.
- We put the MBED back in.
Then we needed a way to disable the Y axis endstop, otherwise it wouldn't get past the homing step on startup. The easiest way to do this seemed to connect our unused Z-axis endstop (Z- for example) to GND.
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IMG_0237_2.png (1.31 MB) IMG_0237_2.png | |||
IMG_0239_2.png (1.37 MB) IMG_0239_2.png |
Replies (1)
RE: Adding a rotation axis (bottle cutter)
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Added by peteruithoven over 8 years ago
I reapplied the changes to the latest firmware version in a separate branch:
https://github.com/Fablab-Amersfoort/Firmware/tree/bottle-cutter