Cherry Pi III Is Available

I have already tried it at a very low travel speed - no different.

I've decided to get myself an inductive sensor like the one Andy's used - that should take delta calibration out of the equation. Unfortunately I'll have to devise a different bracket for it, as I'm currently using the E3Dv6 effector designed by Pointy - Andy's new effector won't take the E3Dv6. I've already got a few ideas about fixing it, although I won't be able to get the sensor as close to the hot end nozzle as Andy's version. I'll also have to work out how to get its cable down to the RAMPS board. Still, nil illegitema carborundum, as they say in these parts...

As an aside - I did a bit more research regarding inductive proximity detectors, and found this interesting circuit. Got all excited because I reckoned that I could easily make a small/specially-shaped sensor with that chip - until I found out that it was an old web page and the chip hasn't been available for years... I haven't managed to find anything else that's as uncomplicated as that chip... rats...

Edited 1 time(s). Last edit at 04/25/2015 10:55AM by David J.

Hi Andy,

I have your printer up and running no problems at all at 100mm/s except my pla is a little dodgy !

The one thing i wanted to do was print new higher "bottom stepper bases" so i acnput a power supply underneath, Could you send me the sketchup file for the ones you sent me which look like a lite version compared to the thingiverse ones.

Thanks Adam

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adambrum
Hi Andy,

I have your printer up and running no problems at all at 100mm/s except my pla is a little dodgy !

The one thing i wanted to do was print new higher "bottom stepper bases" so i acnput a power supply underneath, Could you send me the sketchup file for the ones you sent me which look like a lite version compared to the thingiverse ones.

Thanks Adam

Adam

I had this issue as well and I tapped the bottom of the towers and fitted some swivle feet however that might not be possible if you have used that central channel for cables!!

I also designed some feet that could be mounted to the bottom of the horizontal beams and I have attached both my STL fil and Freecad files for you to look at (Will probably be easier/quicker and less disruptive to your build) you may need to increase the height of the feet depending on the depth of your PSU (I can modify it for you if you wish

HTH Doug

Now why didn't i think of that !

Thanks for that

I needed to increase the spacing between the bottom horizontals of my Kossel in order to fit an IEC mains inlet, so I printed taller frame motor mounts. Having done that, I found there was enough height to fit the power supply under the bed too.

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dougal1957

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adambrum
Hi Andy,

I have your printer up and running no problems at all at 100mm/s except my pla is a little dodgy !

The one thing i wanted to do was print new higher "bottom stepper bases" so i acnput a power supply underneath, Could you send me the sketchup file for the ones you sent me which look like a lite version compared to the thingiverse ones.

Thanks Adam

Adam

I had this issue as well and I tapped the bottom of the towers and fitted some swivle feet however that might not be possible if you have used that central channel for cables!!

I also designed some feet that could be mounted to the bottom of the horizontal beams and I have attached both my STL fil and Freecad files for you to look at (Will probably be easier/quicker and less disruptive to your build) you may need to increase the height of the feet depending on the depth of your PSU (I can modify it for you if you wish

HTH Doug

---

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].

Any one try a cheap IR Sensor with a simple voltage comparator circuit (with adjustable pot) as z probe. (~$10 total)

I have a glass & pcb board heat bed. (I know I will need to put a piece of paper down, or blue tape.) Cant really use a inductive sensor I think.



Edited 3 time(s). Last edit at 04/27/2015 05:45PM by mikes3ds.

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mikes3ds
Any one try a cheap IR Sensor with a simple voltage comparator circuit (with adjustable pot) as z probe. (~$10 total)

Two big problems with that. First, it is very sensitive to the bed surface. Second, it is badly affected by sunlight and incandescent artificial light.

RepRapPro used this approach on their Ormerod 1 kit. They used white targets on the corners of the glass to get consistent reflectivity. But the sensitivity to ambient IR was a big problem. For the Ormerod 2 they switched to a modulated IR sensor. This reduces the sensitivity to ambient IR but doesn't eliminate it completely.

I have sold around 120 differential IR sensors to Ormerod owners to replace the standard ones. They use 2 IR beams to eliminate the sensitivity to ambient IR and reduce the importance of surface reflectivity. They don't need white targets, they work well on plain glass.

---

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].

Well, I've made my mind up - a Duet board has been ordered, and is on its way.

I've also just taken delivery of an inductive sensor, so I'll be working out how I'm going to fit that to my non-standard E3Dv6-mounted effector over the next few days... I have an idea or two, so we'll see how it works out...

One issue that has cropped up is that if you use any sort of zprobe that doesn't use the nozzle as the probe, then any change in the angle between the effector and the bed as the head moves in the XY plane will cause errors in the zprobe height. The further the zprobe is displaced from the nozzle, the greater the effect of any varying tilt. This sort of tilt can be caused by e.g. a pair of rods not being quite parallel because the distance between bearing centres at top and bottom ends is not quite the same, or the carriages rotating very slightly as they move up and down on the towers.

So I suggest you keep your inductive probe as close to the hot end as possible, to minimize the effect of varying tilt.

---

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].

It will probably end up the same distance from the nozzle as in Andy's new effector, possibly 5mm further away. Not exactly sure yet (but something I will bear in mind when I get down to it).

A couple of questions for dc42:

David,

1. I've now got my Duet board - can I follow your instructions for converting the Kossel Mini to Duet when I install the board in my Cherry Pi? Not so much the physical aspects such as mounting the board, but the general set-up and so on.

2. Can I use a 2Gb microSD card? I have one in my cupboard, and it seems a shame to have to buy another!

FYI - the RepRapPro boards no longer come with plain headers for connecting the motors, end stops and thermistors - they now fit the polarised type like this. It's still possible to plug the normal 2 or 4 way connector in though.

I was surprised by the total lack of anything with the board though - just the Duet, in an anti-static bag, and nothing else. Considering the cost, you'd think they'd stretch to a few sheets of paper explaining how it all connects! I'm glad that you've made that list of links...

Thanks,
David

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David J
A couple of questions for dc42:

David,

1. I've now got my Duet board - can I follow your instructions for converting the Kossel Mini to Duet when I install the board in my Cherry Pi? Not so much the physical aspects such as mounting the board, but the general set-up and so on.

2. Can I use a 2Gb microSD card? I have one in my cupboard, and it seems a shame to have to buy another!

FYI - the RepRapPro boards no longer come with plain headers for connecting the motors, end stops and thermistors - they now fit the polarised type like this. It's still possible to plug the normal 2 or 4 way connector in though.

I was surprised by the total lack of anything with the board though - just the Duet, in an anti-static bag, and nothing else. Considering the cost, you'd think they'd stretch to a few sheets of paper explaining how it all connects! I'm glad that you've made that list of links...

Thanks,
David

David

If you look on RepRapPro site they have build instruction's for the Ormerod 1 and that is a good place to start.

As for the connectors that is the norm and they are Molex KK connectors you can get them from Rapid Electronics and IMHO are a much better connector than the Dupont ones (you can't get them the wrong way round. oh and be aware that the endstops will need 3 way connectors outer pins in use IIRC.

I have just got my 2nd board from Replikeo and that came with a 8Gb card and the regulator board (Don't think I will be using that mind)

It is pretty straight forward to set up and I can share my PI4 config.g file if you wish (assuming you have your Pi as fully standard then you will only have to adjust the delta radius rod length and home height to get you going oh and adjust the motor currents to suit your motors.

If you let me know the figures and Motor types I can adjust the file for you?

You will have to download daves files and follow part 3 of his Kossel blog (I Think).

HTH

Doug

Thanks Doug,

I wouldn't mind a copy of your config.g file - more for information/education than anything else.
I can modify it to suit if necessary.

Cheers,
David

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David J
Thanks Doug,

I wouldn't mind a copy of your config.g file - more for information/education than anything else.
I can modify it to suit if necessary.

Cheers,
David

OK here is my Config.g for my Larger slice of Pi it is set up for use with std Cherry pi directions for the motors as if using the std carriages (If you are using Pointy's then you need to reverse the first 3 motors defined.

Keep the homing speed low to start with and have the hotend at half height just to give you chance to hit the panic button to stop it should it go wrong. (I still get worried when i see the hotend heading towards the bed at high speed)

Remember to also alter the Homing file and the BED.g file if you are going to use auto cal

I have attached all my Files first 3 go in the sys folder on the card and the other's go in the macros folder on the card.

HTH

Doug

oh and a 2Gb card should be enough for now and maybe for ever depending on how often you clear out any print files you put in there.

Edited 1 time(s). Last edit at 05/01/2015 08:36AM by dougal1957.

David,

1. Yes. For your config and homing files, I suggest you start from the ones I provide for the Mini Kossel, and adapt them to suit the large dimensions of your Cherry Pi. In particular, you will need to adjust the parameters in the M665 command in config.g, the maximum homing distance in homedelta.g, and the bed probe points in bed.g.

2. Yes, if it is fast enough. The Duet is a little fussy and has problems reading some of the slower types of microSD card. One day I'll dive into the SD card driver and see if I can fix this. Are you sure that there was not an SD card included with the Duet, perhaps installed in the socket already?

3. I am aware that the RepRapPro boards use Molex connectors now. They are more secure than pin headers, because if you use the proper Molex shells to terminate the wires, the shells lock into them and prevent accidental disconnection. This is particularly useful for the stepper motor connections, because disconnecting a stepper motor while it is powered can damage the driver (on ajy 3D printer electronics, not just the Duet).

What revision is your Duet? I believe RepRapPro has recently taken delivery of revision 0.8 boards. These use a linear 5V regulator instead of the switching regulator on the 0.6 board. It produces less EMI, but the current it can provide is much lower.

[EDIT: posting this response was much delayed because the forum server failed with an error message on the first attempt, and Doug has replied in the meantime.]

Edited 2 time(s). Last edit at 05/01/2015 09:35AM by dc42.

---

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 Doug - I'll have a look at those shortly.

My printer is almost entirely standard, with the exception of the effector, which was designed by Pointy for the E3Dv6.

Cheers,
David

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David J
Thanks Doug - I'll have a look at those shortly.

My printer is almost entirely standard, with the exception of the effector, which was designed by Pointy for the E3Dv6.

Cheers,
David

Ah so only the upper clamp pieces then.

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dc42
David,

1. Yes. For your config and homing files, I suggest you start from the ones I provide for the Mini Kossel, and adapt them to suit the large dimensions of your Cherry Pi. In particular, you will need to adjust the parameters in the M665 command in config.g, the maximum homing distance in homedelta.g, and the bed probe points in bed.g.

2. Yes, if it is fast enough. The Duet is a little fussy and has problems reading some of the slower types of microSD card. One day I'll dive into the SD card driver and see if I can fix this. Are you sure that there was not an SD card included with the Duet, perhaps installed in the socket already?

3. I am aware that the RepRapPro boards use Molex connectors now. They are more secure than pin headers, because if you use the proper Molex shells to terminate the wires, the shells lock into them and prevent accidental disconnection. This is particularly useful for the stepper motor connections, because disconnecting a stepper motor while it is powered can damage the driver (on ajy 3D printer electronics, not just the Duet).

What revision is your Duet? I believe RepRapPro has recently taken delivery of revision 0.8 boards. These use a linear 5V regulator instead of the switching regulator on the 0.6 board. It produces less EMI, but the current it can provide is much lower.

[EDIT: posting this response was much delayed because the forum server failed with an error message on the first attempt, and Doug has replied in the meantime.]

Mine from RRP didn't come with anything either.

Doug

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dc42
1. Yes. For your config and homing files, I suggest you start from the ones I provide for the Mini Kossel, and adapt them to suit the large dimensions of your Cherry Pi. In particular, you will need to adjust the parameters in the M665 command in config.g, the maximum homing distance in homedelta.g, and the bed probe points in bed.g.

Understood - I've taken a quick look at the .g files and they seem easy to comprehend.

Quote

2. Yes, if it is fast enough. The Duet is a little fussy and has problems reading some of the slower types of microSD card. One day I'll dive into the SD card driver and see if I can fix this. Are you sure that there was not an SD card included with the Duet, perhaps installed in the socket already?

No SD card, unfortunately. They're obviously doing some economy measures! Mine is a Transcend one, but I have no idea of its performance class - I don't think it's the slowest though. I'll try and see how it goes, and update it if it isn't good enough.

Quote

3. I am aware that the RepRapPro boards use Molex connectors now. They are more secure than pin headers, because if you use the proper Molex shells to terminate the wires, the shells lock into them and prevent accidental disconnection. This is particularly useful for the stepper motor connections, because disconnecting a stepper motor while it is powered can damage the driver (on ajy 3D printer electronics, not just the Duet).

I only mentioned it because in your mini kossel web pages you stress that the version with ordinary pin headers is easier to install!

Quote

What revision is your Duet? I believe RepRapPro has recently taken delivery of revision 0.8 boards. These use a linear 5V regulator instead of the switching regulator on the 0.6 board. It produces less EMI, but the current it can provide is much lower.

Mine has V0.6 written next to the PreRapPro logo - I guess that's the version number. Otherwise, can I identify the version by the ICs and/or components?

BTW: I guess that it won't hurt to have a fan blowing over the card? If so, I'll incorporate one while I'm sorting out the mounting of the board.

Thanks,
David

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dougal1957

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David J
Thanks Doug - I'll have a look at those shortly.

My printer is almost entirely standard, with the exception of the effector, which was designed by Pointy for the E3Dv6.

Cheers,
David

Ah so only the upper clamp pieces then.

It's a bit more complicated - the effector's spacers have been modified so that the E3Dv6 fan can fit in the usual place. This leaves the hot-end block at the level of the lower piece, so the hole has to be a fair bit bigger. It works well, but it will make the fitting of my inductive Z probe... interesting.

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David J

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dougal1957

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David J
Thanks Doug - I'll have a look at those shortly.

My printer is almost entirely standard, with the exception of the effector, which was designed by Pointy for the E3Dv6.

Cheers,
David

Ah so only the upper clamp pieces then.

It's a bit more complicated - the effector's spacers have been modified so that the E3Dv6 fan can fit in the usual place. This leaves the hot-end block at the level of the lower piece, so the hole has to be a fair bit bigger. It works well, but it will make the fitting of my inductive Z probe... interesting.

Yes

I have also used his mounts with 30 mm spacers

Doug.

I am having horrendous problem's with mine getting it to calibrate the effector just will not track across the bed in a true fashion until I can get that sorted it is going no where so may just park it for a while and get the CoreXY going as I have a buyer for my Prusa I3 and I can't afford to be without a working printer so that I can manufacture the parts needed.

Oh by the way I can wholeheartedly recommend one of DC42's PanelDue displays to go with the Duet they are absolutely the Dogs Danglies

Doug

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David J

Quote

What revision is your Duet? I believe RepRapPro has recently taken delivery of revision 0.8 boards. These use a linear 5V regulator instead of the switching regulator on the 0.6 board. It produces less EMI, but the current it can provide is much lower.

Mine has V0.6 written next to the PreRapPro logo - I guess that's the version number. Otherwise, can I identify the version by the ICs and/or components?

BTW: I guess that it won't hurt to have a fan blowing over the card? If so, I'll incorporate one while I'm sorting out the mounting of the board.

Thanks,
David

Yes, that's the version then, so you have a board with the switching regulator - perfect for adding a PanelDue if you ever want to.

A fan won't do any harm, but isn't necessary unless you want to use higher than normal motor currents. I find 800mA enough for the tower motors on my Midi Kossel, except when I want to increase the acceleration so that I can do firmware speed tests. I find 500mA enough for the extruder motor, because I want it to skip steps in preference to chewing up the filament when it can't extrude. If you go higher than 1A, then I suggest you check the temperatures of the A4982 driver chips, and use a fan if they feel hot.

---

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].

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dougal1957
Oh by the way I can wholeheartedly recommend one of DC42's PanelDue displays to go with the Duet they are absolutely the Dogs Danglies

Having just bought the Duet board - I'll have to wait until my bank account catches up! Anyway, I can manage with the printer connected to the computer as that's the way I normally work. I'll consider it once I get the printer working properly with the new board (it was already sort-of working OK with RAMPS, including tracking, it's just the blobby print that knocks the effector out of register that I'll need to deal with once everything's back up and running with the new board).

Edited 1 time(s). Last edit at 05/01/2015 10:40AM by David J.

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David J

Quote
dougal1957
Oh by the way I can wholeheartedly recommend one of DC42's PanelDue displays to go with the Duet they are absolutely the Dogs Danglies

Having just bought the Duet board - I'll have to wait until my bank account catches up! Anyway, I can manage with the printer connected to the computer as that's the way I normally work. I'll consider it once I get the printer working properly with the new board (it was already sort-of working OK with RAMPS, including tracking, it's just the blobby print that knocks the effector out of register that I'll need to deal with once everything's back up and running with the new board).

use ZPL's web interface along with DC42 Firmware and you will love it.

Doug

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dougal1957
use ZPL's web interface along with DC42 Firmware and you will love it.

I've got it downloaded and ready to go!

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dougal1957
I am having horrendous problem's with mine getting it to calibrate the effector just will not track across the bed in a true fashion until I can get that sorted it is going no where so may just park it for a while and get the CoreXY going as I have a buyer for my Prusa I3 and I can't afford to be without a working printer so that I can manufacture the parts needed.

Doug, is the tracking in error across the entire bed, or only near the edges? If it is only near the edges, then for now you could accept a smaller print radius, and adjust the probe points in the bed.g file to reflect this.

---

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].

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dc42

Quote
dougal1957
I am having horrendous problem's with mine getting it to calibrate the effector just will not track across the bed in a true fashion until I can get that sorted it is going no where so may just park it for a while and get the CoreXY going as I have a buyer for my Prusa I3 and I can't afford to be without a working printer so that I can manufacture the parts needed.

Doug, is the tracking in error across the entire bed, or only near the edges? If it is only near the edges, then for now you could accept a smaller print radius, and adjust the probe points in the bed.g file to reflect this.

Yeah I thought about that and I may well have one last try useing that idea however it seems to be ok in the centre and close to the Z towers but goes concave towards the front of the bed it very strange have found the one of my carriages was moving on the extrusion so tightened that up and thought I may have to much tension in the sprins so put the older arms back on (about 35 mm shorter) then there wasn't enough tension.

It's as if the bed is not true to the frame I may try packing the front slightly to see if that makes any difference.

Doug

It doesn't matter too much if the bed is not quite at right angles to the frame - I have that problem, even after trying to eliminate it on my Midi Kossel build. I can still get reasonable (but not perfect) calibration, and I don't think it should affect whether or not the effector tracks at a constant angle, as long as the tower extrusions are straight.

---

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].

Hey Andy, I might be tempted on one of your Cherry Pi IIIS metal machines...could you pm me with costs of a pre-built v a kit?

I'd like to have a go at the kit build but I'm unsure, dont want a box of parts sitting around or a half-built monstrous carbuncle sitting on my worktop for 6 months... the mrs wouldnt be impressed