IR sensor only reads 0  

Re: IR sensor only reads 0

Some people have reported the trigger blade on the sensor being two millimetres too long...

might be worth adjusting the printed part, if all else fails, you can reprint a replacement...

I have no personal experience because I am still awaiting my upgrades.
regards Joan

Re: IR sensor only reads 0

The IR sensor triggers when the invisible beam between the two blades is blocked by an obstruction. Test it with a screwdriver blade. The sensor should switch from 0 to 1. If it doesn't then the sensor may be faulty or connected wrongly to the Einsy. Make sure it is plugged into the correct row of pins, and that the plug is the right way around. See the build manual for guidance.

Re: IR sensor only reads 0

Some people have reported the trigger blade on the sensor being two millimetres too long...

My blade was too long. My sensor would not switch to 0 after assembly, I had to shave down the blade quite a bit until I could get the sensor to operate correctly.

Re: IR sensor only reads 0

I had the same problem. And it turned out the I didnt have the cable properly plugged in.

First, verify whether or not the sensor is working at all, by placing a thin object in the little black plastic 'u' on the sensor PCB. It should read '1' when you do this. If not, then you know that the sensor is not reading at all and that it's not a mechanical issue.

My mistake was the the cable was plugged in, and at first glance, it seemed to be plugged in at the proper location. However it was actually offset a bit to the right (so connector 1 was plugged to pin 2 and connector 2 was plugged into pin 3, etc) I move the plug to proper place and it worked!

Re: IR sensor only reads 0

Exact same problem. Originally I had the cable at the sensor itself plugged in wrong. I don't know if this killed the sensor but I doubt it could because a sensor really only needs a small excitation voltage to produce a signal. Still fixing that and checking all other things made no difference. I have chatted probably 6 times in diagnosing this. After learning of a diagnostic step that was supposedly in the instructions (I can't find it in what I was using) from one of the online techs I did that and still had no luck. After spending more time over the weekend and exhausting everything short of a factory reset (which I was holding for a complete last resort) I finally got a tech on the chat to accept that my sensor is not functioning and I have one in que for a replacement.

I think this is an important upgrade for MMU2(S) functions. Anyone, like me, who has invested loads of filament and dozens of hours to fail near the end or have random missed layers can attest to the need for this sensor. I sure hope its worth it though. It's been exhausting like everything MMU2(S) has been. Until then I'm using 3.5.1/1.03 firmware and it works OK in either single or multi.

Re: IR sensor only reads 0

Third time was the charm, I had the MMU cable lined up wrong and then carried on the error with the IR sensor cable. I thought that lining the cable connector up with the edge of the mother board connector would ensure that the pins were correctly aligned, but that is what made everything offset. The cable connector goes in the middle of the motherboard connector with space on each side. Thanks for the help.

Re: IR sensor only reads 0

I had the same problem. IR Sensor = 0. Always.

First, check to ensure the sensor is working. Using a small piece of paper and putting it in the U channel should trigger a 1. Mine did, so electronics seem to be working fine. If this doesn't work, check the connection on the Einsy board.

However, the blade did not seem to work in the U channel when the chimney is mounted on the extruder. Tried removing the screw that puts tension on the idler door so that it was free to wiggle, but the blade just didn't want to trigger the sensor.

The idler door part was printed (not ordered) in black eSun PETG. Using precision digital calipers, the measurement from the top of the blade to the opposite end of the idler door (max length of the entire part) is 56.49 mm. Measuring the .STL file shows the length should be 56.5 mm, so that looks right. It almost looks like the sensor is not far enough down over the blade.

Next, the cap on the chimney was removed. There are two paths out the side of the chimney that could be used for the sensor wires - one shallow and one deep. Moving the wires from the shallow to the deep fixed part of the problem.

With the tension screw removed from the idler door, the door can fall down lower than normal. This appears to be the second problem when trying to align the sensor. By replacing the idler door screw and then inserting a filament (had to power on, and use menu to engage the extruder axis motor), then the chimney could be adjusted until it read "1". Secured the chimney, unloaded the filament and tested for a "0".

Seems to work now.

Hope that this helps others.

- Brad

Re: IR sensor only reads 0

I've just had this problem too. Thanks for the advice above guys, it lead me to rectify the problem quickly. 🙂

I took the chimney assembly apart and tried waving the probe over there top of the cover arm blade. It really struggled to register a 1 on the screen. I then remembered that PETG is usually transparent material with a bit of die to make it look opaque, so I got a marker pen and scribbled on the blade. That didn't work. But, I then tried a tiny piece of masking tape on one side of the blade and it would register every time I waved the sensor over the cover arm blade. It now working brilliantly and fixed the problem.

So, my conclusion is that the PETG arm isn't always detected by the sensor depending on the material used. I had problems with the old optical sensor and PETG, so this makes sense. I think it would be worth printing that part in ABS. I will try that when I get hold of some black ABS.

Re: IR sensor only reads 0

So, my conclusion is that the PETG arm isn't always detected by the sensor depending on the material used. I had problems with the old optical sensor and PETG, so this makes sense. I think it would be worth printing that part in ABS. I will try that when I get hold of some black ABS.

My sensor arm is mid-green PLA; working just fine.

Peter

Re: IR sensor only reads 0

My sensor arm is mid-green PLA; working just fine.

Peter

That nicely backs up my theory. Thanks.

It makes perfect sense 😉

Re: IR sensor only reads 0

I've just had this problem too. Thanks for the advice above guys, it lead me to rectify the problem quickly. 🙂

I took the chimney assembly apart and tried waving the probe over there top of the cover arm blade. It really struggled to register a 1 on the screen. I then remembered that PETG is usually transparent material with a bit of die to make it look opaque, so I got a marker pen and scribbled on the blade. That didn't work. But, I then tried a tiny piece of masking tape on one side of the blade and it would register every time I waved the sensor over the cover arm blade. It now working brilliantly and fixed the problem.

So, my conclusion is that the PETG arm isn't always detected by the sensor depending on the material used. I had problems with the old optical sensor and PETG, so this makes sense. I think it would be worth printing that part in ABS. I will try that when I get hold of some black ABS.

Not surprising, many plastics are IR-transparent. Whether it works depends entirely on what pigment they use. For example, a pigment-based black (e.g. carbon particles) would work fine, but a dye-based black might very well not if the dye is also IR-transparent.

Re: IR sensor only reads 0

Wow!

I have spent many hours fiddling with the adjustments on the IR Sensor to get it to trigger reliably - adjusting the position of the chimney ever so slightly, adjusting the tension on the idler door, adjusting the tightness of the screw that attaches the door to the assembly. It looked like it was working for a while, but then vibrations or even heat from the extruder motor seemed to make it go out of alignment. A lot of time was spent looking at Support > Sensors and seeing flickering between 1 and 0 during prints.

Then last night, after reading the most recent posts, I took black nail lacquer and "painted" the top tab of the idler door that triggers the IR sensor (be sure to let it dry completely). This morning the sensor seems to work much better. It actually could be aligned pretty easily.

The idler door was printed using eSun PETG. Perhaps eSun uses a dye based color that is not opaque to infrared light.

Thanks for the tips!

- Brad

Re: IR sensor only reads 0

Great news there Brad. 😀

I've just printed the idler door in black ABS and now the sensor registers perfectly every time.

Rigid.Ink black PETG didn't work with the IR sensor BTW.

Re: IR sensor only reads 0

I also am only getting 0 readings on the IR sensor, but I think I have the opposite problem from those whose sensor arm is too long. I believe mine is too short. The sensor works fine when I manually place something between the two halves of it. But when assembled, the sensor arm doesn't seem to quite reach high enough to fully get between the two halves. I'm not sure what I might do to try and correct that.

Everything in the chimney and extruder housing are tight, so I don't see any way to bring the two pieces closer together. If I had a 3D Pen, I might try adding a thin layer on top of the arm, but alas, I don't. I could probably tweek the STL file in Meshmixer, but how do I go about printing it if the sensor doesn't see the filament? Is there a way to get the MK3S to print when the sensor is reading 0?

Re: IR sensor only reads 0

Adding on to the idler arm did the trick for me. I added 1mm to it's length, then through testing ended up removing about 0.2mm of that until I got a consistent 1 when filament was in the gears and a 0 when it wasn't. If anyone has similar issues, I've uploaded the modified stl file here for you to print.

BTW, I figured out that unplugging the MMU from the MK3S would allow me to print without the sensor working.

Re: IR sensor only reads 0

My issue was that the nut on the idler was not pulled in all the way which meant I wasn't tightening the idler enough for it to move sufficiently for the IR sensor to see it. Once I fixed that, the situation is "better" - I still see IR sensor flicker between 1 and 0 when actually printing though. Perhaps I was one of the few folks that had pretty good luck with the old sensor as I find this new solution doesn't work we well so far. I'll keep playing with it though.

Re: IR sensor only reads 0

I initially printed the MK3S/MMU2S upgrade parts in black eSun PET prior to receiving the upgrade kit. After a lot of frustration with the new filament sensor I reprinted the chimney, idler, and cover in the PET shipped in the upgrade kit. May be too soon to tell, but first print seems to be working much better. I did have to file a little off the blade as others have suggested.

Re: IR sensor only reads 0

I also printed in esun black petg. Maybe I should break into that supply that came with my kit too. I can sort of wiggle a 1 to show up with chimney jammed full right and filament in the idler. Then when I tighten the screws it will go back to 0. I'm going to re-design the width of the slot so I can shift a bit more to the right using the step format files in Github. I believe my kit had the chimney with festo receiver in it. Hopefully that festo is just threaded into a pilot hole and not some kind of heat set design.

I assembled according to the instructions. That chimney has 1 fastener with a captured nut and the other a longer screw that looks to form threads in the mating part. I think this design is a little sketchy. I think only 1 fastener is holding all this in place as the short screw with nut is just clamping the nut and maybe some incidental contact with the mating screw hole which makes the chimney pivot.

Anyway to use the printer at all for single color (I'm not confident enough in this to attempt multi-material) I keep having to back out the firmware to 3.5.1/1.03. If I attempt to use this with any newer version loaded it's hit or miss on the extruder just ramming filament through. What a PITA

Re: IR sensor only reads 0

I had same problem. The IR sensor was primarily stuck on 0. When it did work it was sporadic during prints causing problems. The part of the chimney with the festo is a separate piece and came with the kit. I didn't have to reprint that piece.

I'm 3 prints in since reprinting the pieces with the included PET.....so far so good.