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3d printer - Leapfrog creatr conversion
BillTodd:
I have mgfade some progress...
I've built the main control board with a pi pico and relays to switch the main 24v and 240vac heater power, monitor the power button, mains fail and printer shutdown . A bank of supercaps will store enough energy to park the axes and write position to the SD card.
The pico will monitor the gcode data passing from the front panel lcd to the octopus printer board and extract gcodes for bed temperature setting .
More to follow when my brain recovers a bit.
BillTodd:
My aim is to get the printer running again in November.
I now have the bed debugged and the 9 way pid controller working
The solid state relays are mounted on the underside of the bed. Three max335 spi controlled switches multiplex the thermistors back to the Pico ADC and switch the SSRs.
BillTodd:
Not a big update but at least posting here helps to keep me focused...
Pico is now telling Marlin the bed temperature by faking a thermistor (using a PWM pin ) and reading the target temperature from the status report. The LCD asks for an update every second or so, Marlin responds with temperature and targets . The pico sniffs the rx and tx lines and parses the data to Extract the bed temperature.
Still work to do. The solid state relay that was supposed to power on the main 24v smpsu went pop immediately, too much surge current. The fake thermistor needs better filtering .
Overnight thought... The fake thermistor is faking the wrong type of thermistor . I remembered that the leadfrog bed uses a different thermistor. On close inspection, the SSR didn't pop , I had wired the PSU to the heater out relay so what I thought was a pop was just the relay momentarily engaging as the power was cycled. Long story short, it's working fine.
BillTodd:
Bed now controlled from Marlin on the printer
BillTodd:
This is going well... (should I have said that?)
The bed control software is working well , I've a couple of incidental hardware issues to fix .
Today i decided to align the bed : first the rails were trammed using a inclinometer (aka gunners quadrant) - these super accurate adjustable levels , it can easily detect a piece of paper (3 thou") inserted under one end of the bar shown , I'm confident I got the two rails planar to better than 50um.
Tramming the bed-frame was a fiddle , I could level the two front ball-screws using the toolhead mounted DTI , I had to use the Inclinometer for the rear one.
leveling the bed segments was (as mentioned above) a right PITA . I had to trim the tabs of a couple of panels to get them to sit flat with the meeting panels before I could adjust it. Once all the panels were close to zero , so there was a little less interaction between the adjusters ,it was possible to get it flat to better than +/-50um .
If I were to do this again , I'd make the plate from a single sheet and just cut thermal relief slots between segments.
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