Anyone interested in a differential IR Z probe for deltas?

Im interested as well, since my cheap IR probe failed me on unreliable reflectivity across the bed. On what kind of surfaces have you tested this?

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sungod3k
Im interested as well, since my cheap IR probe failed me on unreliable reflectivity across the bed. On what kind of surfaces have you tested this?

I have tested it on plain glass, glass covered with Kapton tape, glass.coated with ABS juice, and BuildTak. I do not recommend using it on mirror glass, because the strong reflection from the back interferes with the weaker reflection from the front that the sensor detects. Likewise, if you have glass on top of aluminium then I recommend putting a sheet of black paper or thin black plastic between them, although it isn't essential.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
sungod3k
Im interested as well, since my cheap IR probe failed me on unreliable reflectivity across the bed. On what kind of surfaces have you tested this?

I have tested it on plain glass, glass covered with Kapton tape, glass.coated with ABS juice, and BuildTak. I do not recommend using it on mirror glass, because the strong reflection from the back interferes with the weaker reflection from the front that the sensor detects. Likewise, if you have glass on top of aluminium then I recommend putting a sheet of black paper or thin black plastic between them, although it isn't essential.

I couldn't find a piec of black paper big enough for my 400 mm diam aluminium bed so I bought a permanent black chisel tip marker pen and coloured the Alloy then the sensor works reliably over 4 mm float glass.

HHTH

Doug

Ah great. As long as it works on paper or sprayed glass, or even the backside of a mirror Im all in. You maybe remember my thread from a few weeks ago with the unmodulated IR probe, which wasn't very reliable across normal paper.

Quote
sungod3k
Ah great. As long as it works on paper or sprayed glass, or even the backside of a mirror Im all in. You maybe remember my thread from a few weeks ago with the unmodulated IR probe, which wasn't very reliable across normal paper.

it works on plain glass but doesn't like a reflective rear to the glass hence the Black paper etc that's why I have given up on the mirror.

Doug

Thanks for sharing the source.

I might just buy your complete IR sensor later down the road. When I have more money.

The IR sensor is only 50 cents if I am correct.
[www.newark.com]


Also replacing R4 with 1K ("In schematic is says R1") will give a digital high, when sensor is triggered at critical point height about 535 reading?
(Or Pin 2 straight to output) I need it to ask like a endstop for the smoothie board.

Edited 3 time(s). Last edit at 05/11/2015 05:20PM by mikes3ds.

I have another 7 mini differential IR sensor boards nearing completion, so I'll be sending Paypal requests to the 6 people on the waiting list tomorrow.

I've made a firmware change and some component changes, in order to provide automatic switching between digital and analog output. After power up, the board now waits 4 seconds to allow the printer electronics to initialize everything, and then senses whether or not there is a pullup resistor on the output pin. If a pullup resistor is found, it provides a digital output that emulates a normally-closed microswitch. If no pullup resistor is found, then it provides a 4-level analog output, which Duet electronics can use to slow down probing as the target height is approached.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

David,

I'm busy designing a bracket to mount the board on my CherryPi delta when it arrives.
Could you tell me the spacing of the 2 mounting holes? And what is their diameter?

Thanks,
David

Edited 1 time(s). Last edit at 05/16/2015 07:36AM by David J.

If the bottom left of the board is at (0,0) then the other coordinates are as follows:

Top left (0, 18.6)
Top right (23.8, 18.6)
Bottom right (23.6, 0)
Hole near top left (2.7, 15.875)
Hole near top right (21.1, 15.875)

The hole diameter is 2.8mm. I supply two M2.5 x 10mm countersunk screws with the board. They are countersunk because the intention is that you print an insulating cover for the board, and use the screws to attach both the cover and the board to your bracket. I'll publish a design for the insulating cover soon.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

More information than I expected!

That's excellent - the info will give me a chance to create something in openSCAD in anticipation of the board's arrival. I'll also draw up a cover to go over the top.

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David J
More information than I expected!

That's excellent - the info will give me a chance to create something in openSCAD in anticipation of the board's arrival. I'll also draw up a cover to go over the top.

I shipped your board (and all the other mini board orders) yesterday - unfortunately, just too late to catch the last post - but I haven't yet got around to updating the status with PayPal. Your board should arrive on Monday. I've included a 3-pin right angle header strip with the latest batch as well as the 3-pin Molex connector. You can choose to use either of them, or neither.

If you haven't already seen it, the fitting instructions are at [miscsolutions.wordpress.com].

My design for the insulating cover for my full-size Ormerod sensor board is at [github.com]. You will need to shrink it for the mini board.

Edited 1 time(s). Last edit at 05/16/2015 05:48PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Excellent news - I'd better get my mount finished!

My mount will protect the back of the board from the hot end (hopefully!) as it will be quite close. However, the component side will be open - is it a good idea to cover the component side of the board to exclude light, or isn't it an issue?

It's no great problem if it should be covered - it will be easy to add it to the design.

Edited 1 time(s). Last edit at 05/17/2015 06:05AM by David J.

Excluding light is normally not necessary. The sensor doesn't like having bright sunlight reflecting directly into it, but is tolerant of most other light sources. But if there is any possibility of the components bumping into towers etc. then you should protect the board with a cover.

Edited 1 time(s). Last edit at 05/17/2015 06:25AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

That makes sense. The board will be in a recess, but adding a cover will be trivial.

One final question (for now!) - is it ok to use ordinary wire to connect to the Duet board, or should I consider screened cable? Ordinary wire would be easier...

David

I wired my full size one with normal wire and it was fine.

It was even in the same bundle as the Heater/Theristor/Bowden tube all inside Spiral wrap.

Doug

Yes ordinary wire is OK.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Z-probe received - small, isn't it!

Quote
dc42
I've made a firmware change and some component changes, in order to provide automatic switching between digital and analog output. After power up, the board now waits 4 seconds to allow the printer electronics to initialize everything, and then senses whether or not there is a pullup resistor on the output pin. If a pullup resistor is found, it provides a digital output that emulates a normally-closed microswitch. If no pullup resistor is found, then it provides a 4-level analog output, which Duet electronics can use to slow down probing as the target height is approached.

Does this mean that in future, if I decide to fit one of these on my RAMPS-powered Prusa, I can just connect it up and go? Assuming that the config is set correctly of course!

Perhaps you should add this info to your mini-probe web page? And while you're in there editing, could you make the Duet wiring diagram a bit larger - or make a 'click-on-the-image' link to a larger diagram? My poor old eyes find the current diagram a bit of a struggle, and I've got a big monitor too...

Thanks for all your efforts,
David

Quote
David J
Z-probe received - small, isn't it!

Quote
dc42
I've made a firmware change and some component changes, in order to provide automatic switching between digital and analog output. After power up, the board now waits 4 seconds to allow the printer electronics to initialize everything, and then senses whether or not there is a pullup resistor on the output pin. If a pullup resistor is found, it provides a digital output that emulates a normally-closed microswitch. If no pullup resistor is found, then it provides a 4-level analog output, which Duet electronics can use to slow down probing as the target height is approached.

Does this mean that in future, if I decide to fit one of these on my RAMPS-powered Prusa, I can just connect it up and go? Assuming that the config is set correctly of course!

Perhaps you should add this info to your mini-probe web page? And while you're in there editing, could you make the Duet wiring diagram a bit larger - or make a 'click-on-the-image' link to a larger diagram? My poor old eyes find the current diagram a bit of a struggle, and I've got a big monitor too...

Thanks for all your efforts,
David

This may help

Duet Proximity sensor wiring

Doug

Quote
dougal1957
This may help

Duet Proximity sensor wiring

Doug

Thanks Doug - same diagram, but a lot bigger!

Quote
David J

Quote
dougal1957
This may help

Duet Proximity sensor wiring

Doug

Thanks Doug - same diagram, but a lot bigger!

Yep taken from the RepRapPro Ormerod 1 docs.


How are you getting on with your Printer I have had a complete nightmare with my extended Pi XL so much so I have purchased a set of Kossel Extruded Aluminium Corner's and converted to full OpenBuild true V-Slot extrusions as I think that the wheels weren't running in the Motedis stuff properly I was getting far to many inconsistancies when trying to Calibrate.

Also think I was getting a lot of movement due to delamination in my original corners (I printed all Parts in ABS (with a 0.6 mm layer height and 0.8 mm nozzle so that may have contributed to it as well) as I want to put the whole thing in a heated chamber for ABS printing This may have to be reserved for the CoreXY Build now and leave the delta just for PLA and PetG).

Doug

Dave's board is tiny isn't it have to design a mount for it now

Mine's coming along, but I hit a brick wall with the RAMPS setup - I just found it a PITA to set things up nicely. Fitting a Duet board made things neater and easier to manage, but I keep thinking of things to add such as the Z-probe, tidying up the power wiring, fitting a power controller for the heated bed, and so on - I've gone from 'just about finished' back to 'I'll get it finished soon'!

The latest thing to tackle was the power supply - I'd designed a nice connection box to hold the USB and XBox sockets, but yesterday I found out that the PSU just isn't up to the job. If I turn on the bed, then the hot-end, and finally try to move a motor or two then a red light would flash on the PSU and everything would reset. So now I have had to redesign the connection box to take just USB and ethernet sockets, and the power wiring will be a pair of flying leads to my existing 30A PSU.

Still, the power wiring is now done, the connection box is made & fitted (just needs its lid), and the Z-probe mount is currently being printed. Maybe the printer will be finished tomorrow...

Nil illegitema carborundum, as the saying goes.

Oh yes... I also decided to design all of these new parts in OpenSCAD rather than FreeCAD, as I was getting really cheesed off with the latter. Glad I did as I've found it so much easier to make minor changes. I've learned a lot of new OpenSCAD commands, and I like using it a lot.

David

Edited 2 time(s). Last edit at 05/19/2015 03:46PM by David J.

I just can't get to grips with Open Scad at all just totally aliegn to me but can do the majority/Basic stuff in Freecad maybe need to try and get to grips with Open Scad but finding the time is not easy!!


Doug

Quote
David J
Does this mean that in future, if I decide to fit one of these on my RAMPS-powered Prusa, I can just connect it up and go? Assuming that the config is set correctly of course!

Yes, that's the idea.

Quote
David J
Perhaps you should add this info to your mini-probe web page? And while you're in there editing, could you make the Duet wiring diagram a bit larger - or make a 'click-on-the-image' link to a larger diagram? My poor old eyes find the current diagram a bit of a struggle, and I've got a big monitor too...

Sorry, the intention was that you can click on the image to get a larger one - but that wasn't working. It is working now. I'll update the text soon to cover the auto analog/digital output switching. BTW for anyone who has already received one with the new firmware, at startup it flashes the LED twice to let you know it is in digital mode, or four times to let you know it is in analog mode.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks David.

I think that an IR probe for my Prusa is a distinct possibility, as currently I'm printing onto an aluminium heated bed covered in kapton tape and it's a pain to replace the tape. I used to print onto glass, but I needed the aluminium bed to allow use of an inductive sensor. I prefer printing on glass... and if I want to put kapton tape on a sheet of glass it's much easier to remove the sheet and do it elsewhere. Often I didn't need the kapton...

I gave up using Kapton tape within a few weeks of assembling my first printer, mostly because I found it too hard to apply the tape without getting bubbles under it (I never tried the wet method). I print PLA direct on glass, and ABS on glass coated with ABS juice. But without the glass, I think you are wise to use the Kapton, to protect the aluminium.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

For PLA I used to use hairspray on the glass - I presume that the IR detector can cope with that? (no different to a smear of stick glue, I guess). ABS juice was also successful.

Quote
David J
For PLA I used to use hairspray on the glass - I presume that the IR detector can cope with that? (no different to a smear of stick glue, I guess). ABS juice was also successful.

Should be no problem, I've used the IR sensor on glass coated with solvent cement, which is similar to ABS juice.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
BTW for anyone who has already received one with the new firmware, at startup it flashes the LED twice to let you know it is in digital mode, or four times to let you know it is in analog mode.

David,

A quick request for clarification from someone who's being chronically thick this afternoon:

Am I right in thinking that

2 flashes = digital = simple on-off switch, for use with something like a RAMPS
4 flashes = analogue = varying values, for use with a Duet board

Just that I've connected everything up to my Duet board, and I'm getting 4 flashes. I think this is correct, but I have sudden doubt...

DON'T WORRY! I've just read the instructions for setting up the sensor, and it explains everything... if all else fails, RTFM...

Edited 1 time(s). Last edit at 05/21/2015 11:31AM by David J.

That's OK, I only updated the instructions to cover the analog/digital output sensing and the LED flashes about 2 hours ago! You may have read the older instructions initially.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dougal1957
I just can't get to grips with Open Scad at all just totally aliegn to me but can do the majority/Basic stuff in Freecad maybe need to try and get to grips with Open Scad but finding the time is not easy!!

I find it reasonably easy - but I have had many years of coding in various languages in the past, so the form and structure of the code is second nature to me. The only down-side is learning all the commands...
I'm also quite good at picturing a design in my head, so I can write up the code with a fair expectation of getting what I want (give or take the odd mistake or so!).

The problem with FreeCAD for me was making modifications - if a change was made to a sketch half-way up the dependency tree then it often broke everything that came after that sketch. I found it too frustrating. With OpenCAD you can change any component at any time you like, and you can also preview just the component you're currently working on, or hide others at will.

Anyway - better not hijack this thread any longer...

Edited 1 time(s). Last edit at 05/22/2015 02:08AM by David J.