Anyone interested in a modulated IR sensor + fan control + illumination board?

I am designing a small pcb to combine a modulated IR sensor, thermostatic control of the fan, and LED illumination of the bed (either on-board LEDs, or power to a LED strip of the sort that some folks are using already). The board mounts on the hotend (so that the sensor is less sensitive to hot end sag) and is used in conjunction with either johneato's modified heatsink duct here [forums.reprap.org] or Matt's modified one-piece duct here [forums.reprap.org], and johneato's modified x-motor mount here [forums.reprap.org]. It would include a 6-pin connector that replaces the current hot end connector, is easier to take apart (i.e. remove and replace individual pins), and is (hopefully) more reliable.

The thermostatic control will monitor the temperature using the existing hot end thermistor, and will include open-circuit thermistor detection. The modulated IR sensor will be usable in two different ways: either with modulation controlled by the Ormerod using a 4th wire (as with my prototype modified sensor, and being developed in parallel by RRP), or with modulation controlled on-board so that it is compatible with the existing 3-wire sensor.

The on-board modulation and fan control will be handled by an on-board attiny24 mcu. If the fan control is not required and the modulation is to be controlled by the Ormerod, it will be possible to populate the board without the mcu.

Before I order parts and PCBs, is anyone interested in purchasing either a bare PCB (estimated cost £4 + VAT + carriage), or a fully-populated board (estimated cost £22 + VAT + carriage)? The assembled price is higher than I would like, but I will mounting the components manually as I don't have automatic component placement equipment. I will open-source the design and firmware sometime after I have shipped the initial batch.

Also, does anyone have any suggestions about anything else that could usefully be incorporated on this board?

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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].

Hi dc42, put me down for one populated board please ( and a bare one just in case ) - is there power or space to shoe-horn a white LED or two in at all?

Cheers

Ray

Could you put me down for a fully populated one

Would it be worth building in support for a force resistive sensor, if I ever get round to redesigning the x-carriage

Edited 1 time(s). Last edit at 02/12/2014 05:52PM by iamburny.

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Ray, yes I was going to include some white LEDs (probably 3 if I can fit them in).

Matt, yes I already had it in mind to allow the FSR to be used in place of the IR sensor - or perhaps as well as the IR sensor?

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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].

[hijack alert] Matt mentioning the FSR reminded me of another indirect but maybe reproducibly useable approach that may be worth investigating which occurred to me today - based on fan vibration. As pointed out by Erik (Ormerod 168?) the vibration of the fan is detectable when pulling paper under the nozzle - it's actually also audible - the bed glass resonates just as the nozzle touches. It may (or may not) be possible to use a piezo coupled to the glass to pick up the (orders of magnitude) increase in fan-frequency sound that occurs just as the nozzle makes contact. It may alternatively be possible to pick up the slight change in pitch and decrease in amplitude as the nozzle couples the fan to the bed from a piezo mounted on the hotend (but this would be problematic since it would probably have to be coupled to the nozzle itself to be effective and may pass the Curie point of the piezo) [/hijack]

Ray

Quote
dc42
a fully-populated board (estimated cost £22 + VAT + carriage)?

yes please..let me know

Dario

I would also like a fully populated board, please. Great initiative; there goes several of the todo list entries :-)

I'm curious about the FSR - is the idea to let it touch the print bed in order to auto-sense Z=0 without IR calibration? Just wondering -- I sense the potential for getting everything a bit higher with regard to the nozzle apart from that. On the other hand, IR calibration still doesn't sound ideal with several bed plates of different thickness, swapping between glass, Kapton and blue tape and so forth, so a more automatic alternative is certainly interesting.

/Allan

dc42 - sorry I obviously didn't read the title or first line of your original post properly, I totally missed the illumination/LED part

Out of interest, how many takers would you need to go ahead with getting some boards printed? I'd be happy with two "minimal kits" if needs be (including programmed attiny, if that's the way it develops, and pcb and connector hardware) rather than one bare and one populated board at the same sort of price - hopefully you'll get enough takers to make this option irrelevant

Cheers

Ray

Edited 1 time(s). Last edit at 02/12/2014 06:35PM by rayhicks.

Ray, interesting idea to use a piezo attached to the bed to pick up the fan vibration - that definitely has possibilities. One problem I can see is that piezos don't like heat, and the bed temperature needed for ABS printing might be too much for it. So I think it would be necessary to insulate the piezo from the bed thermally, but couple it well acoustically.

It's not worth me getting less than 10 pcbs made, the question I need to answer is whether to order more than 10, and how many sets of components to order 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].

Yes please - count me in for a fully populated one

Quote
dc42
Ray, interesting idea to use a piezo attached to the bed to pick up the fan vibration - that definitely has possibilities. One problem I can see is that piezos don't like heat, and the bed temperature needed for ABS printing might be too much for it. So I think it would be necessary to insulate the piezo from the bed thermally, but couple it well acoustically.

It's not worth me getting less than 10 pcbs made, the question I need to answer is whether to order more than 10, and how many sets of components to order initially.

From the late night /first night response looks to me like it'll be worth it, shame we can't run polls on this forum (maybe we can but I can't see the interface) - it would help to tally the "yes" responses.

On the piezo temperature front, the curie point of PZT (the most common piezo material) is around 300°C so there should be no damage at bed temperatures, though there is a marked change in time constant from 100s @ 25°C to 5s @100°C (presumably decrease in capacitance) from various random web info.

Maplin has these at 1.29 or so [www.maplin.co.uk] , and I'll gladly burn a couple on my bed to see what happens - will feedback tomorrow if I get some (I wonder if a dual single rail opamp running off the bed 12V, the first amp feeding into a bridge rectifier with smoothing then into the second amp as comparator would be the easiest way to go?)

You can put me down for a fully populated one as well. And if you're one shy of reaching the 10 you need to order as a minimum, I'll take an extra one as a thank you for your never-ending great advise on this forum, and all the efforts you've put in the firmware updates.
Thanks in advance,

Onno

> fully-populated board
yes please + I hope you will also ship "outside europe" (CH ;-)

I would like a bare pcb if I'm not too late. Unfortunately I'm way behind with upgrading all the parts but live in hope that I will get round to upgrading soon!

Re additional parts. Heres my idea... Maybe you could add some uncommitted breakout pins (dependent on which package you get ? and how much space you have) and give the unused mcu pins extended pads so you can connect them up to them. Then there would be some flexibility to do upgrades using any (maybe upgraded)mcu features.. pwm, serial i2c etc

regards
Andy

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Ormerod #318
www.zoomworks.org - Free and Open Source Stuff

Quote
dc42
... a fully-populated board (estimated cost £22 + VAT + carriage)?..

Thank's much for doing this, put me down for one please!

Erik

And you can put me down for a fully populated (Cos I is lazy) one please.

Mike

Please put me down for a fully populated one please

Thanks
Paul

Quote
kwikius
I would like a bare pcb if I'm not too late. Unfortunately I'm way behind with upgrading all the parts but live in hope that I will get round to upgrading soon!

Re additional parts. Heres my idea... Maybe you could add some uncommitted breakout pins (dependent on which package you get ? and how much space you have) and give the unused mcu pins extended pads so you can connect them up to them. Then there would be some flexibility to do upgrades using any (maybe upgraded)mcu features.. pwm, serial i2c etc

regards
Andy

EDIT I would be keen to have a populated board... but only if you have enough boards to justify get the boards fabbed.. since I know how much work is involved in doing them by hand and it looks like you may have quite a run

regards
Andy

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Ormerod #318
www.zoomworks.org - Free and Open Source Stuff

dc42, have you thought about supplying it as a kit? I'm used to hand assembly of SM parts and I'm sure other people would be too - so long as you don't go lower than 0805 and 0.05" - and you mention doing the assembly yourself by hand anyway. Just a thought as I've been here myself and even fulfilling small orders in the dozens gets to be a real PITA in no time flat. By kitting it in addition to offering the bare PCB you get to buy in bulk and pass some of the savings to customers. Anyway, I'm in for a couple of blanks

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RS Components Reprap Ormerod No. 481

I would appreciate a fully populated board (if it is not getting to much work)

and use this chance to thank you for all the work/suppot done.

Hi

I would be interested in a PCB or a kit of parts if you decided to offer that option.

Martin

Radian, I will be hand-populating the boards with SMD parts and solder paste, then reflow-soldering them. I mostly use 0603 components.

I'm going to do some experiments with vibration sensing - see [forums.reprap.org] - before I finalize the board, in case I also need an op amp to get that working.

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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].

Yes please to a full board DC.
I am concerned at the potential workload for you - and for your sanity. I could imagine making, perhaps, three model airplanes for friends, but if it got to a couple of dozen then I would 'throw in the towel'
So, if the numbers are getting too great, fell free to drop my order in favour of others.
Very many thanks for the amazing work you are doing (I am currently printing your fan deflector)
Greg

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Ormerod #17

I would like a fully populated board as well


Dave

Quote
dc42
Radian, I will be hand-populating the boards with SMD parts and solder paste, then reflow-soldering them. I mostly use 0603 components.

In that case maybe your next project should be Pick and Place RepRap style

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RS Components Reprap Ormerod No. 481

I would like a fully populated board as well

Jan

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XB70

Hi dc

I have been quietly hoping you would go into production on the Modulated IR board save me hacking mine to bits.

Please put me down for a fully populated one.

Thanks,
Dan.

Hello DC,
Yes please - I would like a fully populated one but if it gets too much for you to build a kit of parts would be fine as long as the instructions are good.
Paul

Hi ,
Same as @appjaws , put me down for a populated board, but a kit of parts ok so long as no eagle eyesight required (i.e no surface mount parts or 0.5mm pin spaceing etc ).

Alan

Yes, fully populated board please.
Thanks

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Ormerod #007 (shaken but not stirred!)