Laser wiring?
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@t3p3tony Awesome, thanks.
Do you think the "Circuit operational theory" section I just added looks correct? I want to make sure people are able to understand why they're doing something, not just that they should do it.
https://gist.github.com/keyz182/34601ec4ba4a19c55a177d0d1738d5a3
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by connecting the heater PWM to two input pins of the 74HCT02, we get an inversion of the PWM, such that when PWM out is pulled low, the 74HCT02 output is driven high.
This is a little confusing as written because the diagram shows PWM connected to only one input. maybe re-order the text so it is clear what the 3.3V is doing first?
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@t3p3tony rearranged slightly now - https://gist.github.com/keyz182/34601ec4ba4a19c55a177d0d1738d5a3
I still haven't been able to fully test this yet, I ran out usable filament to print a cable chain mount (I have ABS, but needed to use the room today).
Hopefully I'll get things all tested tomorrow, and can augment the guide with some examples of using e.g. Inkscape to do both vector and raster.
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Added to the wiki - https://duet3d.dozuki.com/Item/Using_a_PWM_driven_laser_module
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@keyz182 thanks, I moved it to a wiki page as it's not really an item:
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Can anyone recommend the best way to protect the signal from interference. The signal cable is running a total of about 1 meter alongside stepper cabling. I could run the cable separately, but would prefer to keeps it clean and together if possible.
I have plenty of shielded Cat5e/6 lying about, would that be fine? How best would I go about utilising the twisted pairs? Tie them together and treat the entire cable as 4 conductors, or e.g. pair signal and gnd? Or should I just experiment and see what works?
Also, does anyone have experience using Cat5e/6 for the steppers? I'd need to check the gauge on the stuff I have, but from what I've read it should be able to handle the NEMA17s I've got.
