Precision Piezo Z-probe Now available.

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Dancer
sounds to me like a broken wire inside the insulation. When moving to this exact position the wire is bent so it does not have contact anymore. moving on to the next point it is bent another way, contacting again.

I once had this Problem in the wire to the heater cartridge on the hotend. Had to search some weeks until I noticed, because Temperature was swinging when moving. Did PID tunings, changed Fan duct, put insulation on hotend - nothing helped. One day it was broken that much, i got thermal runaway. Scratched my head some eventings until I noticed it was always on front right where there was maximum bending on the wires...

Do you work as a automobile mechanic ?

They too start by replacing the most expensive and unlikely parts (ECU, unrelated actuators, sensors...) before looking at the basics (fluid levels, fuses, connectors, wires...).

Personally I always start by pulling, pushing, hammering, cussing then if it fails, start to apply "Problem Solving & Decision Making" (KEPNER TREGOE)

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

ah okay guess I should change out the wires then. Thanks!

That's probably the answer and it is at least a fairly cheap place to start.

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

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MKSA
Do you work as a automobile mechanic ?

They too start by replacing the most expensive and unlikely parts (ECU, unrelated actuators, sensors...) before looking at the basics (fluid levels, fuses, connectors, wires...).

Sounds like you've had some bad experiences there. I can say that isn't the way the auto mechanics that |I choose to pay operate, but then I'm a car guy myself, and more or less rebuilt my car from the ground up.

I do apply the same troubleshooting to my hobbies as I do to my car, and I don't like spending money on replacing parts if I can make an existing part do its job. My winter beater car is a bit past the line, to the point where I'm about to just give up on it entirely.

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SupraGuy

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MKSA
Do you work as a automobile mechanic ?

They too start by replacing the most expensive and unlikely parts (ECU, unrelated actuators, sensors...) before looking at the basics (fluid levels, fuses, connectors, wires...).

Sounds like you've had some bad experiences there. I can say that isn't the way the auto mechanics that |I choose to pay operate, but then I'm a car guy myself, and more or less rebuilt my car from the ground up.

I do apply the same troubleshooting to my hobbies as I do to my car, and I don't like spending money on replacing parts if I can make an existing part do its job. My winter beater car is a bit past the line, to the point where I'm about to just give up on it entirely.

Some tried but not for long.
Note, relatives and friends always ask my advice.
OK, not all mechanics do that of course. Just a few are crooks but the complexity of today's car is such that many are totally lost and act let's say randomly.

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

I'm having an issue getting my piezo sensor working properly, and the site said to post here for support so that's what I'm doinig.

I bought 3 Andromeda boards and the universal PCB. I managed to make it work great, but it only works for a few seconds. Then it completely stops working and I have to either unplug and replug the board or turn the printer off and on again to get it working. It works instantly again after power cycle.

Video of behaviour here:
[www.dropbox.com]

Does anyone have any ideas of what I'm doing wrong, or does this look like a bad board?

I tried with multiple different Andromeda boards and also with a plain piezo disc, and am getting the same behaviour.

Thanks in advance,
Alex

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alexspeller
I bought 3 Andromeda boards and the universal PCB. I managed to make it work great, but it only works for a few seconds. Then it completely stops working and I have to either unplug and replug the board or turn the printer off and on again to get it working. It works instantly again after power cycle.

That is not normal behavior.

I'm using the Andromeda sensors and a generic board. (It's a regular v2 board, not the v2.75 in your video, but I have a v2.75 board, too, which works the same.)

I don't think it's the Andromeda sensors. For starters, the liklihood of all 3 going like that is so low as to be ridiculous. Therefore the PP board would be the suspect.

The behavior right after reset looks right, with the blue light flashing on activity. Sensitivity tuning seems correct, it doesn't seem to take excessive force on the sensor to react. what Vin voltage are you feeding it?

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

Hi Alex,

Sorry I've been slow to reply to your email, life is very busy at the moment.

What kind of controller board are you using?
Do you have pullups enabled?
Are you able to measure the voltage of the SIG pin when the Uni board is plugged into your controller?

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

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SupraGuy
what Vin voltage are you feeding it?

The supply is 3.3v

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Moriquendi
Sorry I've been slow to reply to your email, life is very busy at the moment.

What kind of controller board are you using?
Do you have pullups enabled?
Are you able to measure the voltage of the SIG pin when the Uni board is plugged into your controller?

Idris

No problem!

I'm using a Duet Wifi board, and the board is connected to the zprobe header.

I don't know if that means I have a pullup resistor or not. The config I'm using right now is M558 P1 I1 R0.4 F240

So that's analogue mode, which does report sensible values in the duet web UI whilst the board is working for those few seconds. I tried some other modes too with M558 and same results.


Voltage between SIG pin and GND pin is at 0.53V

Thanks,
Alex

There should be a pullup on the Duet Wifi (That\s what I'm using, too.) That is NOT a good setup for your M558 definition. Mine is as follows:

M558 P8 H8 F780 I1 T9000 R0.8 Z1 ; Set Z probe type to unmodulated and the dive height + speeds

edit: This was from an older backup of my config. I have since edited the dive height and speed, but this works. I'm also using hte piezo as the Z endstop, as you see here.

It may treat the signal pin and pullup differently when not in digital mode. I would suggest that you re-define the M558 and see if that changes behavior.

Edited 1 time(s). Last edit at 01/18/2019 12:06PM by SupraGuy.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

I recommend using mode 8 (P8) in place of P1, the output of the board is digital.

The voltage at the SIG pin when untriggered (red LED lit) should be the same as V+, in this case 3.3v. When the board is triggered (blue LED lit) the voltage on the SIG pin should be 0v so something, somewhere, is going wrong.

Are you able to measure the voltage of the pin on the Duet where the SIG pin would connect but without the Universal PCB connected? This should be 3.3v

What behaviour are you seeing from the LEDs?

Idris

Edit: That's a very good point Supraguy, I think it would have to disable the pullup in analog modes.

Edited 1 time(s). Last edit at 01/18/2019 12:11PM by Moriquendi.

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

OK, I've gone back to my original config which is "M558 P8 I1 R0.4 F240" - I only changed to analogue mode when I couldn't get digital working as the docs said it gave finer-grained control and my first thought was that I was just under the trigger threshold or something.

With that mode set, voltage at the SIG pin is 3.3v either plugged in to the piezo board or not (well, Duet calls it the Z_PROBE_IN pin). In analog mode it's about 0.5v plugged in or not, so looks like changing to analog mode changes the voltage at the Z_PROBE_IN pin on the Duet board.

No change in behaviour though

Alex

What are the LEDs doing?

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

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Moriquendi
What are the LEDs doing?

Same as in the video, no change. Specifically, at power on the blue LED is on for a few seconds. Then the blue LED goes off and the red LED turns on.

Tapping the piezo causes the blue LED to turn on and the red to turn off, along with triggering the zprobe in the duet web ui - so this seems like correct behaviour to me.

Then after a few more seconds, the red LED stays on and tapping the piezo no longer triggers any change in LED status or in duet web ui reported status, so it seems to have just "frozen" on red / untriggered.

Very strange...

Rather than messing about with trying to work out what's going wrong, I'll send you a replacement, would you be able to return the board you have to me?

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

This kind of service is why I'm happy that I paid Idris for my piezo sensors. He's been really good to me, too.

The described behavior definitely says that the Duet disables the pullup resistor for analogue monitoring. Good to know.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

Great, that makes sense to me, thanks!

Can you email me the address you want me to send it to? I don't think I have one for you from the order docs.

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SupraGuy
This kind of service is why I'm happy that I paid Idris for my piezo sensors. He's been really good to me, too.

The described behavior definitely says that the Duet disables the pullup resistor for analogue monitoring. Good to know.

This is the normal way to do as it is an input.

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

Well, this just happened today I was away from the printer when it broke so didn't see what caused it. Guess I need to find someplace to print a new top for my Orion Module.

Happened to me a couple months ago as well.

Anybody know why the ID of the top is 6mm? For direct drive peeps at least, seems it'd be a lot tougher if it was closer to 4mm OD of bowden tube.

@p40whk; Sorry to see that, can you PM me your order number and I'll send you a replacement. I'm assuming you were printing at the time? The nozzle probably hit the print, there's quite a long lever between the nozzle and the mount so it can apply quite a lot of force.

@Wescherry; It's to allow for the larger bowden tubes of 3mm filament. Also, adding material near the centre of the cylinder doesn't add much strenght.

I had some issues with this part early on but I thought I'd fixed them, I'll check again and see if I can make any improvements.

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

Well, it is pretty fragile and it’s layer adhesion that’s the issue so any extra meat is going to help.

It’d be great to have a 4mm od bowden version.

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Moriquendi
Very strange...

Rather than messing about with trying to work out what's going wrong, I'll send you a replacement, would you be able to return the board you have to me?

Idris

Received the new board today, worked perfectly without any changes to my setup, so it looks like it was just a bad board. Hopefully you also received the old board back by now.

Many thanks for the prompt replacement!

Alex

I currently have an FSR setup on my non-heated Delta bed. It's an aluminum plate that rests on the FSR's (with cork pads), the sensors are built into the tops of 3 towers at the centers of my base extrusions, which also keeps the bed nicely level.

Question: Does the board tuning work like the JohnSL board, in that it can "tune" or set zero at the current pressure sensed?

If so, it sounds like nearly a direct replacement without much more than a couple new printed towers to make the switch.
I'm interested in decreasing the force necessary for probing and increasing repeatability, as it sometimes fails calibration (1of4).

Thanks Much!

The piezo element responds only to changes in pressure, it automatically adjusts to the weight of the bed. The tuning is only required to achieve minimum probing pressure while avoiding false triggers due to vibration.

You may find the accuracy and repeatability are improved by having the bed positively fastened down rather than just resting there, particularly when probing outside of the triangle formed by the mounts. You might find the Andromeda PCB sensors interesting.

Idris

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{Precision Piezo} Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters.

Cool, I'll probably hit the shop later today then.

My bed is constrained somewhat at the edges by the corner covers I made, and pieces of aluminum angle bolt to the horizontal extrusion's outside face and reach up over the plate to keep it from lifting on opposite side probes. It cannot move around or lift, but can be depressed to activate the current sensors I have.
It triggers with a firm tap of the finger, but I'd like mostly to tighten the group of numbers returned for several calibration runs (smoothie reports repeatability at the end of auto-calibration).

Here's a pic, 3mm bolt is through a 6mm hole so that the bracket is widely adjustable but holds firm when tightened. There's zero gap at the plate.

Would appreciate some ideas for better delta bed mounting for Andromeda boards.

So, I got the new universal PCB and it seems to work fine, I tuned it as suggested in the docs and it triggers when I tap my bed reliably.

However, it does not trigger reliably by hotend probing at all, so it doesn't seem sensitive enough and I suspect I am mounting the Andromeda boards badly.

I've attached a picture of how they are mounted, so they are on the openbeam extrusion, with the bed tab on top, and a m3 bolt through the bed support tab and the board, tightened not massively tight but enough to hold in place. There are 3 of these supports at equal angles around the bed. Since any force to the bed should result in compressing the Andromeda boards through the bed mounts, I thought that this arrangement should work at least temporarily until I printed some better supports and mounting that at least don't have part gouged out with pliers for the connectors!

Any suggestions / pointers / thingiverse links for the type of mount I should look to design for a delta bed? I thought that even though my arrangement is makeshift and ugly, it was at least conceptually sound, but now I don't think it is but I'm not sure what a correct design would look like.

Thanks,
Alex

@Alex: I can't see from that picture what is supposed to apply pressure to the Andromeda board.

Generally speaking, what you want is a mount where pressure from the hotend against the bed will try to flex the Andromeda circuit board. This is usually done by mounting the ends to the frame, and the center to the bed. In that case, Irdis' example drawings show this quite well.

in your picture, it looks like you just put the bed mounting bolt through the Andromeda board into the frame. This isn't going to work. I don't know what the other side of that printed piece looks like, but I assume that it holds the bed, and you chipped some out to make room for the Andromeda's connecgtion.

Try mounting the Andrometa to the frame by the end holes, on stand-offs, then use a shorter screw to mount the bed to the center of the Andromeda. you will probably want to change the printed mount to only apply pressure to the center of the Andromeda, or you can put a nut on the bottom of the piece between it and the Andromeda to do the same thing. You'll loose a few mm of print height doing this.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

@SupraGuy that's clicked and made a lot of sense, I think I know what I need to do now.

Thanks!

Is there a drawing of the Orion board like for the Andromeda board?
How big of a hole can we have in the center?