Youyue 858D+ some reverse engineering + custom firmware

[Gixy]

Just to be sure : which firmware has to be used for MK1841D3 board with Waynes's adapter? The one provided by Wayne or the original from Robert?

[Christe4nM]

A place to watch: http://www.heartoftechnology.com/reverse-engineering-the-858d-hot-air-rework-station/

He's traced out the full schematic for the YouYue 858D+

As far as I've read, he's planning to do a complete redesign of the control board.

Thanks for mentioning my blog. I am indeed working on a redesign. It's in progress and I haven't been able to find time to update my blog or start a topic here. Here is just a tiny teaser of the board in progress. (Just to be clear: I don't want to hijack this tread, so let's keep it on Madworm's firmware and directly related)

[wguibas]

Just to be sure : which firmware has to be used for MK1841D3 board with Waynes's adapter? The one provided by Wayne or the original from Robert?

It's the same firmware, It just has this 1 line edited.  The files I provide are just the compiled hex files with the change done already

Original code from madworm:
temp_inst =analogRead(A0) + temp_offset_corr.value;   // approx. temp in °C


For the samsung chip board it's

temp_inst =(analogRead(A0)/1.9) + temp_offset_corr.value;   // approx. temp in °C

For the MK1841D3
I'm still tweaking the number but it's somewhere around 2.3-2.4

temp_inst =(analogRead(A0)/2.4) + temp_offset_corr.value;   // approx. temp in °C



I also changed the default low and high FAN SPD limits to 130 and 400.

[Gixy]

OK, clear. And this is this value which could also depend on main voltage.

[Jetiman]

#FAN-speed mod https://github.com/madworm/Youyue-858D-plus-FAN-speed-mod/blob/master/youyue-858d-plus-fan-speed-mod__schematic.pdf
If the C1 and C3 100n  a  100nf ?

And C2 = 1 µF but C4 = 1µ?

[madworm]

n == nF
µ == µF

[wguibas]

OK, clear. And this is this value which could also depend on main voltage.

I'm not sure yet, technically reporting the temperature back to the chip is independent of the power heating the air, it would just get hot quicker.  But, if the electronics are different for the 220v vs 110v, even just a resistor, then the calibration could be way off. 

[madworm]

And C2 = 1 µF but C4 = 1µ?

What's wrong with 1µF for C4? A bit of decoupling doesn't hurt. Just a few cents for the cap.

[Votality]

Hi guys a little off topic but I'm considering getting one of the 858d's clones is anyone able to help me get up to speed on the differences between the models and different sellers.

I.e atten 858, yihua ,youyue, scotle.

I'm guessing given this thread that the temperature regulation isn't perfect on the youyue and needs some improving. Are the other brands any better (atten etc). Also you guys seem to talk about a number of different controller boards. Can someone recommend a particular ebay seller and brand and why. (Sorry not up to speed on all the variants) edit: After reading through the forum it appears you guys recommend the youyue can anyone recommend an ebay seller for a known good quality clone.

[giovannirat]

A big thank you to madworm for investigating and solving the RST problem on 858D+

Changed both of my 858D+ to V1.44 and all problems gone !

[bianchifan]

The issue is as follows:

The code provided by avr-libc that turns off the watchdog timer (see previous assembler code) requires that register R1 (zero-reg) is ZERO. This is usually the case, but not when said code is put into the memory section ".init1". The intention for that was to have the code run as early as possible.

Last time I did some register programming was 1985
Last use of a cross-reference list in the early 90th..

Please get V1.44 and test :-)

I'm still happy with my personal variation of v 1.37 - having-a-beer-smiley

I think that 90% of today's Arduino users wouldn't be able to find such a bug.

You may rise the number to 99% and more...
Those shit is the reason why some clever people developed JAVA

I wonder sometimes why Atmel&Co are still alive..  

[Gixy]

Hi Wayne,
Back from skiing holidays. I've found your adapter board in my mailbox: many thanks for providing me with an already programmed Atmel chip.
On which pin of the potentiometer shall I connect the FANSPD wire? I tried to compare this device (Kaleep) with the schematic at www.heartoftechnology.com but there the fan speed is sensed with a divider on the fan wires, not on the pot.
Looking forward to reading from you and test this upgrade..
Denis

[wguibas]

It solders to the inner most pin of the pot.  My board has the divider on it with the two resistors on the front bottom left.

[Gixy]

I saw the divider. Thx for the photo. I'll keep you informed as soon as the upgrade is done.

[Gixy]

Hi Wayne,
Yesterday night I installed your board in my 230V Kaleep 858D+. Everything went well at start-up : firmware version, fan ON during approx 3 seconds then OFF, operationally it works (no reset, no errors).
Then I began to measure the temperature with a DMM/thermocouple just at the output of the smallest nozzle. I did two runs from 50°C to 400°C upwards and backwards.
Here are the results, compared with the original version with MK1841D3. You can see that there is a big difference between the displayed set point and the real temperature. An other issue is that when increasing the set point the value is achieved without overshoot, as when decreasing there is always a large undershoot (between -20°C to -30°C) before going back to the set point. Let me know if you need some more information to adjust the parameters accordingly. Shall I try to play with the calib pot? Thanks in advance,
Denis

     MK1841D3                            ATMEGA328P               
Set point   Run #1          Set point    Run #1      Run #2          Mean delta           %
  50°C         53°C               50°C        37°C         38°C                 12,5°C           25%
100°C       106°C              100°C        73°C         70°C                 28,5°C           29%
150°C       147°C              150°C       112°C       110°C                39,0°C           26%
200°C       191°C              200°C       154°C       149°C                48,5°C           24%
250°C       234°C              250°C       204°C       203°C                46,5°C           19%
300°C       275°C              300°C       250°C       249°C                50,5°C           17%
350°C       317°C              350°C       295°C       291°C                57,0°C           16%
400°C       363°C              400°C       337°C       330°C                66,5°C           17%
350°C       320°C              350°C       299°C       294°C                53,5°C           15%
300°C       283°C              300°C       258°C       255°C                43,5°C           15%
250°C       240°C              250°C       214°C       210°C                38,0°C           15%
200°C       198°C              200°C       156°C       155°C                44,5°C           22%
150°C       156°C              150°C       115°C       114°C                35,5°C           24%
100°C       113°C              100°C        77°C         82°C                 20,5°C           21%
  50°C         54°C               50°C        38°C         40°C                 11,0°C           22%

[madworm]

Ran a test with the 858D+. Nonlinear temp delta. Possibly due to airflow restriction effect with small nozzle. Needs new calibration for each nozzle diameter and ideally lookup table or decent nonlinear fit on data. No time now to fix it right.

[Gixy]

Thank you Robert,
I'll try another set of measurement with the other nozzles. I don't remember well, but it is possible that I made the MK1841D3 measurement with the middle-size nozzle.
I also set the fan at level "6", knowing that the "FAN" menu shows 145 and 375 as extreme values.

[madworm]

Felt like doing another test run. This time I aligned the temperature probe coaxially with the 7mm nozzle & chose a fan speed of 4.5 ripms. The results were quite different and much better. It didn't go up to 500°C, but that is due to restricted airflow. Once I cranked the fan up to max, temperature went up. Too bad the sensor can't be at the exit of the nozzle.

I've changed the firmware a bit (not yet released, probably V1.45). There is now a config option in the menu (like the PID parameters) to show raw adc values instead of "temperature". Makes it much easier to record calibration data :-)

[Gixy]

Did something similar last night with the 7mm nozzle. The probe was at 45° from the nozzle axis, 3mm from its output. Fan speed at 5. I notice that fan speed has not a big influence on the exhaust temperature at low distance. All in all I confirm that results are much better, around 7 to 12 degrees of difference at much, after having also played with the calibration potentiometer (but not with the temp_corr parameter which is set at 33).

A real issue is that when I tried to set the target temp at 500°C, the temperature suddenly rose up, above 650°, which made the heater body and nozzle becoming blue and gold, and the probe red... I just had time to lower the target before ruining everything.

[madworm]

The blueing does happen. 650°C should have triggered an auto shutdown and temp error. Maybe the heater is stronger and the PID parameters don't quite fit your model.

[Gixy]

This is the Kaleep device, with the adapter board from Wayne, but it is a 220V/700W. This indeed may imply different PID parameters, although below 450°C everything went well.

[GiantGnome]

I just got my board from OSHPark, and I have assembled it and tried it out on my 220V Kaleep 858d+

My temperature probe only goes to 250°C, so that is what I tested by hand-holding the probe over the nozzle-less handle. It went almost straight to 250, with a small overshoot to 251°C. When i turned it back to 170°C, it went all the way down to 127°, slowly rising to 155°C and stayed there.

I clearly need to do more testing and I have only changed one line in madworms code, I need to check if I need more code changes. I used an atmega88pa, but a few corrections to the makefile later, it was no problem.

Quick tip: Do not use an angled programming header. I have to unplug the board to reprogram it  . Luckily OSHPark sends you three boards :-)

[steve41993]

Hi GiantGnome,
your PCB looks pretty nice  . I try to make one for the MLF package of the ATMEGA328P. So im searching for schematics. Can you send me yours please?
Just following the traces of the design from wguibas and match them up is a bit unreliable.
I have to do this because I want to put it on a PCB with an other layout. Got a bit room left on my 10cm x 10cm order by elecrow. (I cant import the gerber files and place them on a existing layout in Altium. Maybe there is a way, but I cant find it.)

[GiantGnome]

Thanks, Steve 

I have made my schematic by following the traces. So, no guarantees at all. The basic functionality seems to work (buttons, display, temperature settings), but I have not tested fan speed sensing and the like.

I should probably upload my entire KiCad project to some place, but here is the schematic I made for it. It's not pretty, but it made it possible for me to lay out the board.

The OSHPark project is here https://oshpark.com/projects/vLy9R74P .

Wguibas, madworm, Is there somewhere I can throw a small donation your ways? I feel like I am freeloading on your hard work.

[steve41993]

Hi,
thanks for the schematics . I compared your schematics with my schematics and they match up.
I will start the layout tomorrow and post the results here.
And thanks to all who worked on this project 

Edit: The layout is now finished (untested!). Ordering will be in the next few weeks. So testing is possible in maybe two months.
Download project files: https://goo.gl/ixK7Va