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New hot end board: pre-order yours now!

Posted by dc42 
New hot end board: pre-order yours now!
May 30, 2014 09:35AM
I'll shortly be ordering the production PCBs for my new hot-end board (I'm just waiting for a sunny day so that I can test the prototype in bright sunlight). I need to decide how many PCBs order and assemble, so I am accepting pre-orders now. Provisional prices are at the end of this post. The board has the following features:

Height sensing

* Uses 3-way modulation to detect the difference in the light reflected by the surface of the bed from two IR LEDs.
* No need for white tapes, so can be used anywhere on the bed, e.g. in the centre when z-homing.
* Works well on bare glass, Kapton tape, and glass coated with solvent cement. Other surfaces should be OK as long as they are uniform and reflect some IR.
* Not affected by reasonable amounts of ambient IR, such as from incandescent lighting. May need to be shielded from direct bright sunlight. The board will report if there is too much ambient IR.
* Height is sensed at a spot close to the y-offset of the nozzle, so the height reading is less affected by varying head sag than a sensor mounted on the x-carriage.
* Back-up mode provided (simple modulated IR sensor) for x-homing use, in case the x-homing tab is not at a suitable height to use with 3-way modulation. Switching to back-up mode requires a 4th wire in the sensor loom.

Fan control

* Thermostatic control of the hot end fan. Fan will be on if the hot end temperature exceeds approx. 41C or if it is showing very cold (possible disconnected thermistor). Fan will be off at normal room temperatures.

Lighting

* Three Cree LEDs with constant current drive illuminate the bed in the region of the nozzle.

Indication

* Amber LED at the top of the board indicates that the hot end heater is on. Brightness of the LED will vary with heater power.
* Small red LED on the board edge indicates that the height sensor is triggered.

Connectors

* 8-way connector for hot end loom.
* 4-way connector for sensor loom.
* 2- way connectors for fan, thermistor and cartridge heater.
* All connectors are polarised and mounted on the board.
* Connectors are compatible with my previous hot-end boards.
* The original floating 6-pin connector is no longer used.

Mounting

* Secures to modified heatsink duct using two M2.5 screws (supplied). Mounting points compatible with my previous hot-end boards.

Firmware compatibility

Compatible with recent dc42 firmware releases. When used with RRP 0.65 firmware, the sensor will work in 3-way modulated mode only.

Other features

* Option to use the constant current driver with your own external LEDs instead of LEDs on the board.
* 12V pads provided for connecting your own 12V strip lighting
* 2 spare pins on the on-board ATTINY44A microcontroller brought out to pads for hacking
* 2 spare pads for 0603 components provided for hacking

Specifications (preliminary, subject to change)

Trigger height: approx. 2.5mm below bottom edge of board.
Height reproducibility between different surfaces (3-way modulation mode): 0.1mm or less when changing between bare glass, Kapton tape, and solvent cement.
Output G31 readings (3-way modulated mode): 0 = too high, 465 = getting close, 558 = triggered, 1023 = too much ambient IR.
Output G31 readings (simple modulated mode): 0 = tab not detected, 558 = tab detected, 1023 = too much ambient IR.
Fan supply voltage: 11V min. (for correct operation of illumination), 30V max. (fan FET limit)
Fan current: 1.5A max continuous.
Heater supply voltage: 20V max. as supplied. Increase LED series resistor (0805 SMD type) for higher voltages.
Illumination LED current: 20mA as supplied, can be increased to max. 60mA (subject to power dissipation in constant current driver) by adding a resistor (0603 SMD type)

Options available to special order

Component value adjustment to suit 5V power supply instead of 3.3V (for use with pre-Duet electronics)
Firmware adjustment to suit different hot end thermistor 25C resistance, or different thermistor series resistance
Low value output resistance, so that the board can emulate a microswitch instead of the IR probe

Tools required for assembly

1.5mm allen key
Crimp tool recommended e.g. HT-225D (available at reasonable prices from Rapid Electronics and via eBay)
Soldering iron and solder (not required for fully soldered boards)
Working 3D printer, to print replacement heatsink duct etc.

Provisional prices including delivery, for payment by PayPal:

	                UK inc VAT   EU VAT paid  Europe no VAT  Outside EU
					
Bare PCB	        £7.34	     £8.36	  £6.97          £7.65
Full kit	        £44.44	     £51.84	  £43.20  	 £44.00
Full kit soldered   	£52.84	     £60.24	  £50.20  	 £51.00
Upgrade kit	        £38.44	     £45.84	  £38.20  	 £39.00
Upgrade kit soldered	£46.84	     £54.24	  £45.20   	 £46.00

All kits have the SMD components soldered on the board and the microcontroller programmed and verified. "Soldered" kits also have the through-hole components soldered on and the board fully tested. The "Europe no VAT" column applies to purchases both by EU but non-UK businesses that are registered for VAT, and to deliveries to countries within Europe but outside the EU. Upgrade kits are for those who already have one of my previous kit 3, 4 or 5 boards, and are supplied without the crimp pins, header shells, wire and screws.

To reserve your board, please send me a PM or email giving your forum name, PayPal email address, what you want, your delivery region, and your VAT number if you are an EU but non UK business. Current shipping estimate is end of June. I will send payment requests via eBay when the boards are imminent. If you require more than one board, please contact me with the details so that I can work out the delivery charge. If you are already on the waiting list for one of my kit 5 boards and wish to be taken off that list, please let me know.

Note that if all you want is a sensor that works reliably with the white tapes in the corners of the bed even in the presence of ambient IR, then there are a couple of lower-cost solutions: (a) wait for RRP to release their modulated IR sensor board, or (b) if some people decide to cancel their existing kit 5 orders because they want to wait for the new board instead, then I can produce a few more of my Kit 2 or 3 boards at a special low price.

Edited 10 time(s). Last edit at 05/30/2014 06:50PM by dc42.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
May 30, 2014 01:24PM
Could you remind me which parts need to be printed to use this board (and where they can be found) - I'm afraid I've lost track of all the variations.

Dave
(#106)
Re: New hot end board: pre-order yours now!
May 30, 2014 02:14PM
The printed parts needed are:

1. Modified heatsink duct, or modified version of Matt's one-piece heatsink/fan duct.

2. Sensor pad to extend x-homing tab around the front of the z threaded rod.

3. Insulating cover.

All can be downloaded at from [github.com].



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
May 30, 2014 02:47PM
Full Kit soldered please.
Re: New hot end board: pre-order yours now!
May 30, 2014 02:59PM
Quote
dc42
The printed parts needed are:

1. Modified heatsink duct, or modified version of Matt's one-piece heatsink/fan duct....

..or johneato's Control air to the nozzles version, have used it with your kit 5 since started ABS printing, I think its great!

[forums.reprap.org]



Erik
Re: New hot end board: pre-order yours now!
May 30, 2014 06:41PM
I've just added a small red LED to the specification, to indicate when the height sensor has triggered. This should make it easier for those who use Pronterface to control the printer and so don't have a continuous read-out of the z-probe output.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
May 31, 2014 04:56AM
Thanks!

Erik
Re: New hot end board: pre-order yours now!
June 01, 2014 05:09AM
Thanks to all of you who have sent me PMs to reserve boards. So far I have orders for 14, which gives me enough confidence to make 30. I'll order the boards today so that assembly can start about 2 weeks from now.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 03, 2014 03:17PM
Thanks to all who have sent me PMs or emails. I now have enough interest commision a batch of 50, and I have ordered 100 PCBs.

I received a good offer for assembly of fully-soldered boards, so I have decided to offer them fully-soldered only. For those of you who wanted fully-soldered boards anyway (the majority), the price has come down by GBP3.00 (+VAT if applicable). Those of you who were prepared to solder the through-hole components yourselves will have to pay another GBP4.00 (+VAT if applicable). But you will receive a fully assembled and tested board.

So here are the new prices, all fully-soldered, including carriage:

	        UK inc VAT   EU VAT paid  Europe no VAT  Outside EU
					
Bare PCB	£7.34	     £8.36	  £6.97	         £7.65
Full kit	£54.04	     £61.44	  £51.20	 £52.00
Upgrade kit	£47.44	     £54.84	  £45.70	 £46.50



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 10, 2014 08:03AM
A few updates:

1. Thanks for all the provisional orders. As there are nearly 30 of them, I haven't acknowledged them all individually. I will send payment requests via PayPal when the boards are nearing completion, which should be near the end of this month.

2. We finally had a sunny day here, so I tested the effect of sunlight shining on the bed. The only way I could get the sensor to saturate was by removing the sensor board from the hot end, holding it a few mm above the bed, and rotating it so that the area of the bed directly under the sensor was not in the shadow of the board or anything else. This is in contrast to the TCRT1000 sensor used in my previous board and RRPs board, which saturates much more easily. I also tested it with a 60W incandescent light, and I had to move the bulb to within 5cm of the bed and sensor head to get it to saturate.

So the differential IR sensor is even more resistant to sunlight and other ambient IR than my previous board, which was already nearly 100 times less sensitive to it than RRP's unmodulated board. About the only way I think you could get it to saturate in real use is with strong sunlight falling on the bed at a shallow angle. If the sensor does saturate, it signals this by giving a z-probe reading of 1023 to alert you.

3. The bare PCBs have been manufactured and are on their way to me. I have ordered 100 PCBs, and I will get 50 of them assembled initially.

4. Here are some scope traces of the signal from the phototransistor, showing how the 3-way modulation works. First, with the sensor above the target height and returning a G31 reading of zero:

:

The base level is with both LEDs off, so it is the response to ambient IR. The shoulder is the response to reflected light from the LED closest to the phototransistor. The peak is from the LED farthest from the phototransistor, showing a strong reflection from the surface of the bed.

Next, when the sensor has detected that it is approaching target height and set the G31 reading to 441 (so that the Duet knows to slow down the z motor):



The reflection from the far LED has reduced a little, and the reflection from the near LED has almost caught up with it.

Now the Goldilocks moment, the reading has just jumped to 576:



Both reflections are of equal intensity.

Finally, with the sensor too low, still reading 576:



Now the far LED is reflecting much less strongly, and the near one strongly.

Edited 1 time(s). Last edit at 06/10/2014 08:04AM by dc42.



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

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

Re: New hot end board: pre-order yours now!
June 11, 2014 09:04AM
While I have been getting good results with my switch I am tempted by one of these.

A couple of slightly off topic questions if you don't mind dc.

  • Where do you get your boards made?
  • Is your ATTiny SMD and how are you programming it?


Regards,

Les


Pointy's Things
Pointy's Blog
Re: New hot end board: pre-order yours now!
June 11, 2014 10:21AM
Hi Les,

I'm getting the PCBs made by Itead in HK and the boards assembled by Castle Technologies in Stranraer.

Yes the attiny44a is SMD. The board includes pads for a standard 6-pin Atmel ICSP header, but I don't populate it because it would increase the height of the board too much. Instead, I use a programmer attachment with 6 spring-loaded probes that I press on to those pads.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 11, 2014 11:29AM
I have put the draft installation instructions for this board at [miscsolutions.wordpress.com]. Some of the photos will need updating when the production boards arrive.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 12, 2014 12:18PM
Quote
dc42
Hi Les,

I'm getting the PCBs made by Itead in HK and the boards assembled by Castle Technologies in Stranraer.

Yes the attiny44a is SMD. The board includes pads for a standard 6-pin Atmel ICSP header, but I don't populate it because it would increase the height of the board too much. Instead, I use a programmer attachment with 6 spring-loaded probes that I press on to those pads.

Thanks for the info dc,

Itead seem really cheap for small PCBs, I might give them a try when my design is finalised. Is your programming probe a commercial product or home made?

Back on topic, please put me down for a full kit.

Regards,

Les


Pointy's Things
Pointy's Blog
Re: New hot end board: pre-order yours now!
June 12, 2014 12:44PM
Hi @DC - if you still have some available, please put me down for a fully soldered upgrade kit - thanks
Re: New hot end board: pre-order yours now!
June 12, 2014 01:07PM
The programming probe is home made. I soldered 6 spring loaded test probes on to a 2x3 header.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 13, 2014 08:06AM
Hi dc42,
I'm interested in a full kit, but I don't need fan control - I'm happy with my PWM fan already. Would it be possible to use your IR sensor board for lighting and Z-height measurements only? And will this board work at a bed temperature of 120°C?
Re: New hot end board: pre-order yours now!
June 13, 2014 09:03AM
Hi zpl,

First I would caution against using a single PWM fan. The heatsink needs to be cooled whenever the hot end is hot. So if you want to control the fan speed then I suggest you use one on/off fan to cool the heatsink, and a separate PWM fan to cool the print.

However, if you want to then you can bypass the fan control on my board by soldering a 0 ohm 0603 resistor or a wire link across the pads provided for this purpose.

Regarding use at a bed temperature of 120C, the IR emitter and phototransistor at the bottom of the board are rated at 85C. There is also a capacitor at the bottom of the board, rated at 105C. If the bed thermistor is reading 120C then I think you will find that the bed surface is at more like 105C. I think it would be advisable to provide cooling for the IR emitters and phototransistor, perhaps by drilling a small hole in the heatsink duct.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 14, 2014 09:21AM
Hi dc42,
thanks for your reply!

Quote
dc42
First I would caution against using a single PWM fan. The heatsink needs to be cooled whenever the hot end is hot. So if you want to control the fan speed then I suggest you use one on/off fan to cool the heatsink, and a separate PWM fan to cool the print.

There is absolutely no problem using a 4-pin PWM fan for the hotend cooling. As per Intel's specifications, all 4-pin PWM fans will run at somewhere near 35% if the PWM line is pulled low or the duty cycle decreases to less than 30%. In fact, this limitation even makes them idiot-proof and allows me to utilize the M106/M107 commands quite nicely.

Quote
dc42
However, if you want to then you can bypass the fan control on my board by soldering a 0 ohm 0603 resistor or a wire link across the pads provided for this purpose.

Regarding use at a bed temperature of 120C, the IR emitter and phototransistor at the bottom of the board are rated at 85C. There is also a capacitor at the bottom of the board, rated at 105C. If the bed thermistor is reading 120C then I think you will find that the bed surface is at more like 105C. I think it would be advisable to provide cooling for the IR emitters and phototransistor, perhaps by drilling a small hole in the heatsink duct.

Thanks for these tips, I'll measure the maximum temperature 2.5mm above the heated bed when it's at 120°C, and if it doesn't exceed 85C, I'll let you know about a new order! I thought about drilling an extra hole, too, and it might be another option if the temperatures are actually too high at Z=2.5. I hope this won't be necessary, though.
Re: New hot end board: pre-order yours now!
June 14, 2014 10:11AM
Quote
zombiepantslol
There is absolutely no problem using a 4-pin PWM fan for the hotend cooling. As per Intel's specifications, all 4-pin PWM fans will run at somewhere near 35% if the PWM line is pulled low or the duty cycle decreases to less than 30%. In fact, this limitation even makes them idiot-proof and allows me to utilize the M106/M107 commands quite nicely.

zpl, I think you have misread the Intel specification. It says that the minimum fan speed shall be 30% or less. Even if your particular fan is outside the specification and runs at 35% minimum speed, are you certain that 35% is enough to cool the heatsink sufficiently, at the ABS hot end temperatures that I presume you are using? I guess you have probably blocked off the outlets if you are printing ABS, so perhaps it is.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 14, 2014 10:42AM
I use iamburny's fan duct, and when I print the first layers with ABS with the cooling turned off by the Duet, the cooling at ~35% is absolutely sufficient for the hotend. I've been printing more than 1kg of ABS at 250C with this configuration and I have not had any problems since I mounted the new PWM fan. Before I switched to my current PWM fan, I was using a simple 40x40x10 fan and that one had basically the same throughput as my current one running at minimum speed. I can't say how well this would work with other PWM fans, but it's perfectly safe with the SunOn fan I have here.
Re: New hot end board: pre-order yours now!
June 16, 2014 02:17AM
Hello, excuse my English (google translated).
Could I ask you a question?
How did you create the base of your pieces?
How do you create top closure pieces so beautiful?
How did you set the program Slic3r?
thanks
Re: New hot end board: pre-order yours now!
June 19, 2014 09:30AM
Here is a quick update. I have just assembled two pre-production boards:



I'll test them this afternoon, then if all goes well I shall place the order for 50 to be assembled.

I already have provisional orders for 31 boards, so there are 19 more available from the first batch.

The draft installation instructions are at [miscsolutions.wordpress.com] although some of the photos need to be updated.

Edited 2 time(s). Last edit at 06/19/2014 09:32AM by dc42.



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

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

Re: New hot end board: pre-order yours now!
June 19, 2014 03:33PM
Hi there,

do you ship this out to South Africa? I am interested in this as I've been struggling with the current sensor for a day and a half, he he.

thanks,
derrick
Re: New hot end board: pre-order yours now!
June 19, 2014 05:41PM
Yes I can ship to South Africa.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: pre-order yours now!
June 20, 2014 12:01AM
Hi dc42,


it´s like christmas..... cant wait to upgrade my ormerod......
Re: New hot end board: pre-order yours now!
June 20, 2014 03:22AM
The pre-production boards are working well and I have placed the order for manufacture. I should have the boards ready to test and ship about 2 weeks from now.





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

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

Re: New hot end board: pre-order yours now!
June 20, 2014 03:53AM
Hello DC42.
Could you offer me a total price for 1 full kit (electrics and plastics parts)
I have a problem to printer!
My mail: simosartori76@gmail.com
Thanks.
Bye
Re: New hot end board: pre-order yours now!
June 20, 2014 05:02AM
Hi Simon, I'll send you a quote by email.

What is the problem that is preventing you from printing? It is possible to use the printer without a working z-probe.



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

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: New hot end board: shipping from 1 July!
June 24, 2014 06:17AM
Thanks to all who have sent me provisional orders. I expect to start shipping the boards next Tuesday, so I will send PayPal requests for payment starting today. Regrettably I have had to increase delivery charges a little, because it turned out that I was losing money on carriage. Here are the final prices, for payment by PayPal:

	        UK inc VAT   EU VAT paid  Europe no VAT  Outside Europe
					
Bare PCB	£7.35	     £8.48	  £7.07	         £7.82
Full kit	£54.63	     £62.89	  £52.41	 £53.50
Upgrade kit	£47.56	     £55.75	  £46.46	 £47.52

If you have pre-ordered a board and do not receive a request for payment before the weekend, please PM me.

I have orders for 33 boards so far, so there are still 17 available from this batch.

I have posted the schematic at [github.com].

Edited 1 time(s). Last edit at 06/24/2014 07:07AM by dc42.



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

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