@lo-fi, I just wanted to say thanks for this design! I have two different MFM's (a 1.7 and a 1.7b), using this mount has actually made the 1.7b useful and reliable. Before switching to this mount, I honestly just kept the MFM disabled and used a microswitch in front of the MFM for filament monitoring. I always wanted to get the sensors working reliably, though I never could get consistent performance out of them. The other day I decided to try troubleshooting them again and came across your post here. Wow, what a difference. Thank you again so much for actually making my sensor useful.

I hope that this model will be added to the doc page for the MFM when you and Phaedrux think it's ready. I think there are probably other people who will appreciate it too.

Here is my configuration for the bltouch
; Z-Probe
M574 Z1 S2 ; Set endstops controlled by probe
M307 H3 A-1 C-1 D-1 ; Disable heater on PWM channel for BLTouch
M558 P9 F100 H5 T6000 R0.2 A5 B1 ; Set Z probe type to bltouch and the dive height + speeds
M280 P3 S140 I1 ; Enable 5v logic for BLTouch
G31 P25 X-22.00 Y-16.00 Z0.29 ; Set Z probe trigger value, offset and trigger height
M557 X20:180 Y20:180 S15 ; Define mesh grid

@lo-fi, I just wanted to say thanks for this design! I have two different MFM's (a 1.7 and a 1.7b), using this mount has actually made the 1.7b useful and reliable. Before switching to this mount, I honestly just kept the MFM disabled and used a microswitch in front of the MFM for filament monitoring. I always wanted to get the sensors working reliably, though I never could get consistent performance out of them. The other day I decided to try troubleshooting them again and came across your post here. Wow, what a difference. Thank you again so much for actually making my sensor useful.

I hope that this model will be added to the doc page for the MFM when you and Phaedrux think it's ready. I think there are probably other people who will appreciate it too.

@Grudairian I double checked before I started splicing wires, and the step-up converter is intended to handle 24V at 10A, which means that it should need about 20A at 12V input to maintain that. If a single atx pin is only intended to handle 6A at 12V then the wire is probably not rated for too much more than that either. I checked and the wires are 20AWG from the PSU. So now I am thinking that the best course of action would be to take 4 x 12v lines off the PSU and solder all of those together with the positive line in on the step-up converter. That should provide 24A at 12V for input and should be enough power to keep the step-up converter happy. For the 4 12v lines, I figured I would sacrifice the 8 pin cpu connector. I also figured if we are allowing for that much power to go in, we should also allow it to get out and figured I would also splice grounds to be equivalently rated.

Thanks again for your reply, it has been good food for thought

@Grudairian I just wanted to add that when I was looking through the questions on the amazon page for my hotbed, someone mentioned that the hotbed should draw about 25 amps(at the 12v config). Looking on the side of the PSU it looks like the 12v lines are rated for 35A. So it seems like splicing the step up converter directly to the 12v line might be a good idea and would get around the 6A limitation of an atx connector.

@TDK Thanks for replying TDK. The printer did run in this set up for almost a year so it seems odd that it would blow in less than a week with the new board. Though the old I breakout board had the two 12v lines tied together and this one keeps them separate.

I checked, and it looks like the hotend should only be pulling about 1.67A, but I can't find wattage or amp draw for the heatbed. Do you think setting up the hotbed on a separate mosfet directly from one of the 12v lines would work to reduce the amps across the connection to a safe point?

Alternatively, I could bypass the breakout board for the 12v line going to the step-up converter and splice/solder the step up converter directly with the 12v line from the psu.

Do you have an approach you would recommend?

So my printer has been running perfectly happy for almost a year now, about a week ago I smelled a bit of burning plastic, and started to get warnings that Drivers 0,1,2,3,4 were over temperature and the print would come to a complete halt. I figured I would check the wiring and ensure there were no problems. Well, I was shocked when I detached the ATX PSU and found the 12v lines on the breakout board charred. Upon detaching the breakout board from the frame of the printer, the positive 12v lead just fell out of its connector.

To power my printer, I was running from a 450w EVGA ATX PSU into a breakout board, and from there I connected to a 12v->24v Step up converter before feeding 24v power into my duet board. I had seen the warning on the duet wiring guide that all connections should be in crimped ferrules and that you should not use tinned connections. But... I didn't have the equipment to properly crimp the included ferrules, and I figured that if I clamped the screws down hard enough I would be okay. It looks like the step-up converter I used had tinned ends though. It's my belief that over time the connection was heated by the high currents passing through and the solder or tinning began to run. As the solder began to run, the connection became poorer and the resistance increased. Eventually, the connection failed.

To repair the problem I ordered a ferrule set with crimps and reseated all of my screw terminal connections on the printer. I replaced the breakout board, and I cleaned the contacts on the ATX connector.

This week, however, I have run into a problem with the new breakout board burning out as well.

I don't want to keep throwing parts at the problem and I want to get to the bottom of what is going on so I had a few questions for people who are more knowledgable than myself.

The first thing I want to do is ensure there are no shorts anywhere in my system. To do this I was planning to use my multi-meter to check the power lines coming off the duet mainboard. Specifically, I was planning to check the hotend heater cartridge, and the hotbed by checking the resistance across them from their wires that currently connect to my duet. Do you think just checking resistance will work? Do you have any idea what resistance I should be expecting? (E3d high precision 24v 40W and Anycubic 43188-247109 12v/24v ultrabase and heated) Obviously I expect to find some resistance and no resistance would imply a short, but what I mean is, do I need a particular resistance to be confident there is no short?

Next, I plan to replace the breakout board again, and I am concerned the step up converter may have been damaged in the first incident. If so my guess is that there may be a short or problem with the step up converter that caused the second problem. Do you know if there is any way I can safely test the step up converter?

Lastly I was wondering if there is any way that I can check to see if the ATX PSU needs to be replaced? or if the connections might still be okay. The 5v line is still working and the duet can power up, but I cannot turn "on" the power from the web interface anymore, which is probably cause the 12v power line has a charred connection. (I realized there was a problem with the power again when I saw that the web interface listed the vin as 1.7v and had the red off icon indicating the psu was turned off. I tried to turn on the PSU and when it wouldn't do so inspected the connection and found the second problem.)

p.s. I want to mention that I do have a smoke detector mounted above the 3d printer, and especially with covid, I am almost always in the same room as the printer.

@Danal Hi Danal, thanks for the pointer to the servo and pin control page, but I am specifically trying to trigger an IFTTT trigger without having anything wired directly to the duet. I glanced through the servo page you linked, but I didn't see anything that seemed directly related to the process of setting up an IFTTT trigger from the duet. I apologize if i missed something.

Just a thought, would it be possible to setup the pinouts to fire on an event(print start, etc) and have something like a raspberry pi listen for a pin event? Then when the raspberry pi receives the pin out signal it could trigger an IFTTT event? I would prefer not to have to use a second board to make this work, but I am open to ideas.

@bearer is there any chance you could tell me more about how one might set this up? I have some wifi connected led's that I currently control with my google home assistant (I really enjoy being able to adjust colour and brightness with voice commands). I would really like to set up IFTTT triggers to change their colour based on gcode, so as to have visible status indicators (I also think IFTTT triggers would enable fancier effects, such as pulsing colour that would be challenging to achieve with the pinout system). I am happy to add gcode to my start, and stop or pause commands.

I recently saw a Thomas Sanladerer video where he talks about setting up leds based on pinouts, and my hope is to find a way to achieve a similiar status effect with IFTTT triggered events.

https://youtu.be/fb3hrjEiE3s

I was trying to figure out my sensors quirks a bit more today, and I updated from 2.04 to 2.05 ( firmware is here: https://github.com/dc42/RepRapFirmware/releases/tag/2.05). I was still having a problem with negative values being reported for the min range on M561 D0, so I reviewed the set up page again. I saw a new argument that I am going to test, but it might help you too.

"An (firmware 2.03 and later) 1 = check All extruder motion, 0 = only check extruder motion of printing moves (moves with both movement and forward extrusion)"

I'm hoping that this will keep my min range more reasonable, and I thought it might be useful for you too.

I'm glad you are running the right firmware, I'll keep watching this topic to see if anyone else can help you with it. I understand your frustration with having to hit resume every 30 seconds. At the moment I have my magnetic filament sensor set to S0 so it can monitor filament, but it disables the sensor from pausing the print. So it kind of seems pointless to even be running the thing. I need to spend more time figuring it out some time. I hope someone here will be able to help you, they have always been helpful when I have come here with questions.

I picked up a magnetic filament sensor about a month or two ago, and while I haven't completely nailed down my problems with it I keep getting negative min %), I did find that my duet board firmware was causing a lot of problems. Up to that point, I was running whatever firmware came with the board and I hadn't had any other problems. I updated to 2.04 and my magnetic sensor started working. Can I ask which firmware you are running? It should be available on your Machine specific tab, and the current release is 2.05. If I recall correctly you need to be running at least version 2.03 for the sensor to work properly. I was still on ~1.9, it connected but was a nightmare.