Author Topic: Youyue 858D+ some reverse engineering + custom firmware  (Read 196553 times)

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Offline DGM

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #650 on: April 28, 2018, 10:38:02 pm »
I went to try finding newer examples of Atten internals and I found something interesting.  There appears to be a new kid on the block -- at least new to me.  The most interesting part is that it's an AVR-based design and the firmware behavior appears similar to the older Atten units.  The board is entirely different than anything else in this thread.  Because the panel layout is different, it should be easy to identify, and there's less uncertainty of the board type within.  None of the other boards would even fit.




aliexpress turns up results for "mypovos 858d"

I had avoided looking for references on YT because it's basically impossible to do it effectively on a <1Mbit network connection.  It's incredibly slow to skim videos, and at 240p, you can't see board marks or anything relevant.  I may see if there are other bits to add to the index, but don't count on it.

Offline HotAir

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #651 on: May 30, 2018, 05:44:14 pm »
Hello!
Got this one today, attached photos of PCB, as DGM said above, it's AVR based, and also it looks like have a different heater element.

I don't have a thermal couple to check how accurate is, but I had seen one comment in Aliexpress, some one says it's accurate, and as you can see it does not have a calibration.

Bought it for about 30€, I was able to take the Youyue 858D+ for the same money. So what do you think, it is have advantages to taking this instead of Youyue 858D+?
In case if it will be inaccurate, the custom firmware can be modified and loaded for it also, right?
« Last Edit: May 31, 2018, 02:41:27 pm by HotAir »
 

Offline Gabse

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #652 on: June 02, 2018, 05:32:50 am »
 Hey Guys,
I have a hacked 858D station an I am pretty happy with it. The station needs quite long to cool down if the fan speed limited (specially with the small nozzle), so I worked out a hack to make the speed switchable via Software. The Trick is to add a Transistor which shorts the potentiometer slider pin to ground. I used a BC547B, because I had it around, but any NPN Transistor should work. The current through the Transistor and the potentiometer bias resistor is about 5mA Which are 125mW on the Resistor.



On the Microcontroller side I used the until now unused PB3 (MOSI) Pin, because it should be easy accessible on most adapter boards. It is switched on when the hot hand piece is put in the cradle and also in Fan Test mode to get a accurate reference. I also improved the Handpiece-not-in-cradle-mode, because I think this way it saves some time on startup. Software is available on my GitHub page and  will hopefully be merged to madworms Page.
Cheers,
« Last Edit: June 02, 2018, 03:50:03 pm by Gabse »
 

Offline DGM

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #653 on: June 03, 2018, 12:20:14 pm »
Hello!
Got this one today, attached photos of PCB, as DGM said above, it's AVR based, and also it looks like have a different heater element.

I don't have a thermal couple to check how accurate is, but I had seen one comment in Aliexpress, some one says it's accurate, and as you can see it does not have a calibration.

Bought it for about 30€, I was able to take the Youyue 858D+ for the same money. So what do you think, it is have advantages to taking this instead of Youyue 858D+?
In case if it will be inaccurate, the custom firmware can be modified and loaded for it also, right?

I didn't notice that this variant had no cal pot.  I wonder what the tolerance stackup is with all the resistors in the TC amp.  Maybe it's not a terribly big deal, but I haven't gone back to the schematic to check ... or checked this board against other AVR 858D schematics.  The worst-case scenario would just require calibration in firmware.  I suppose I should start adding AVR-based 858D maps to the board index, shouldn't I? 

So long as it functions well, I don't know why you couldn't use the alternative firmware.  It might take some remapping of the IO pins, but that's simple enough.   I suppose the big advantage that you get with AVR versions in general is the ability to drop a new MCU in the thing.  All the 20-pin types (like the 858D06 board in the current Youyue) need an adapter board of some sort.

If you do decide to try the alternative firmware and care to share your pin mapping, I'll gladly add it to the index. 

Hey Guys,
I have a hacked 858D station an I am pretty happy with it. The station needs quite long to cool down if the fan speed limited (specially with the small nozzle), so I worked out a hack to make the speed switchable via Software. The Trick is to add a Transistor which shorts the potentiometer slider pin to ground. I used a BC547B, because I had it around, but any NPN Transistor should work. The current through the Transistor and the potentiometer bias resistor is about 5mA Which are 125mW on the Resistor.

On the Microcontroller side I used the until now unused PB3 (MOSI) Pin, because it should be easy accessible on most adapter boards. It is switched on when the hot hand piece is put in the cradle and also in Fan Test mode to get a accurate reference. I also improved the Handpiece-not-in-cradle-mode, because I think this way it saves some time on startup. Software is available on my GitHub page and  will hopefully be merged to madworms Page.
Cheers,

I'd thought about that too, but I was kind of thinking that it could just be done in hardware.  I kind of figured it would suffice to pull the wiper down whenever the optotriac drive was inactive.  The only issue would be that you'd need some sort of delay to keep the mod inactive during normal heater switching operation.  I suppose a diode, cap, mosfet and a resistor would suffice.  If overshoot causes a long enough off-time to trigger the mod, it would likely only improve overall settling time. 

Of course, my entire approach would be problematic if you wanted to implement a blower-only mode with controllable speed.  Control through firmware is ultimately more flexible.
« Last Edit: June 03, 2018, 12:25:40 pm by DGM »
 
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Offline HotAir

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #654 on: June 04, 2018, 02:15:39 am »
Hm, in the Chinese manual which came with it, there is mention about temperature calibration(photo attached), here what I translated with google translate

"1, in the welding state, measure the actual temperature value, and record
2. In the welding state, the colleague presses the “▲” and “▼” keys to display “CAL”, when the release shows three small dots below the displayed value, Immediately enter the measured temperature (performed within three seconds). After the correct input, press the "▲" and "▼" keys simultaneously to display the "CAL" temperature calibration."

I have tried this method, however it does not work, strange...  :-// I will try to ask other peoples in youtube, if their station can be calibrated, so to understand, if all those models can't be calibrated or just mine have an issue.

Few days ago ordered a thermometer with thermocouple, in few weeks it should arrive, then I'll test how accurate is that 858D
 

Offline Gabse

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #655 on: June 04, 2018, 02:55:59 pm »
I'd thought about that too, but I was kind of thinking that it could just be done in hardware.  I kind of figured it would suffice to pull the wiper down whenever the optotriac drive was inactive.

You could use the reed switch signal to switch the transistor every time the heater is in the cradle. That should work too, the only downsides are, it doesn’t work in Fan test mode, and if the heater is switched on all the time due to a broken TRIAC.
 

Offline DGM

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #656 on: June 04, 2018, 06:09:56 pm »
You could use the reed switch signal to switch the transistor every time the heater is in the cradle. That should work too, the only downsides are, it doesn’t work in Fan test mode, and if the heater is switched on all the time due to a broken TRIAC.

Oh, the reed switch.. /me facepalms
but really, not much protects against the inevitable stuck triac in these designs.

From my experience incinerating ebay SSR's and BTA26-800's by the dozen, I kind of learned to regard chinese triacs as a pending failure.

Offline HotAir

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #657 on: June 19, 2018, 04:41:10 am »
I asked on youtube some peoples with same station, they said the calibration on their station is also does not working.

However, today I received my thermometer with thermocouple, did some quick tests, and found out that when I hold the thermocouple very close to the nozzle, almost inside, then the temperature is very accurate, like about 0 - 10 °C difference.
 

Offline DGM

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #658 on: June 21, 2018, 12:50:16 pm »
As far as i'm concerned, that's good news. 

The offset between the internal thermocouple and an external thermocouple is going to vary with distance, fan speed, and nozzle size.  Trying to cal for somewhere significantly beyond the end of the nozzle is going to be fairly pointless unless you never change the nozzle or fan speed.
« Last Edit: June 21, 2018, 12:52:15 pm by DGM »
 

Offline fordson

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #659 on: July 08, 2018, 01:02:16 am »
Hi forum ,


I also have the HD 858d v1.0 mainboard with the unlabeled processor.

I tried to understand all info given in this tread , but i am i kind of lost ...............( mus tbe age ).

Is there already an adapterboard available which has been tested by someone ??  ( i have downloaded the eagle files already )
What is the result of this ?? , is it working with the custom firmware ?? ( also downloaded ) .


any help highly appreciated .




fordson


 

Offline bwack

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #660 on: July 08, 2018, 07:05:44 am »
fordson, at least the HD 858d v1.0 board is in the index two pages back in this thread.

Offline fordson

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #661 on: July 08, 2018, 11:16:43 pm »
Yep , i have already downloaded all files i could find related to the HD858D v 1.0 .

But...................is there already someone out there who has managed to get it modded and working .

unfortunately i am a bit rusty in reverse-engineering  :scared:






As aliexpress is selling them by the thousands ...................


 

Offline DGM

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #662 on: July 13, 2018, 07:34:43 am »
I only made the adapter layouts, but I do not have the boards to test them on.  You can always try to contact one of the members who have the Hyiko 858D's and ask them if they've pursued the mod.  IIRC, Miwer had expressed interest at least. 

http://www.eevblog.com/forum/reviews/youyue-858d-some-reverse-engineering-custom-firmware/msg1317403/#msg1317403
http://www.eevblog.com/forum/reviews/youyue-858d-some-reverse-engineering-custom-firmware/msg1328274/#msg1328274
http://www.eevblog.com/forum/reviews/youyue-858d-some-reverse-engineering-custom-firmware/msg1364083/#msg1364083
these links are in the reference index (I added yours)

If you are comfortable with making the adapter and programming the AVR, tailoring and debugging isn't that much more..
Sanity check the layout before you make the adapter.   Go over your board and make sure that the pin map in the index and eagle files matches what you see.
You'll also need the DMM to measure the voltage on the ADC so that you can calculate the ADC scaling for the TC.
I mentioned this in a post a few pages back, or there's a sheet in the index spreadsheet for calculating the scaling factors.

If you're worried about the risks associated with the heater control, just disconnect the heater from the board until you're sure the code appears to be working. 
You could probably even use a heat source (lighter or something) on the TC to demonstrate that the ADC is working and that the firmware turns the heater off.
That way you won't have to worry about roasting the heater if there's an issue with the code.
I don't think there's any checks in the code that would make such a test problematic (someone can correct me)

Offline Miwer

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Re: Youyue 858D+ some reverse engineering + custom firmware
« Reply #663 on: August 02, 2018, 06:33:47 pm »
You'll also need the DMM to measure the voltage on the ADC so that you can calculate the ADC scaling for the TC.
I mentioned this in a post a few pages back, or there's a sheet in the index spreadsheet for calculating the scaling factors.

Just adding a lille note on this.
I did actually make an adapter board for the Hylko model, but the temperature afterwards was all wrong of course. I wanted to use the firmware without modifications, but that require that I match the ADC input voltage range to the original adapter, and it was a bit harder to tune in, than I anticipated.

The problem with the Hylko model and the 858D-1.0 board is, that the unlabelled chip has no dedicated input for ADC reference voltage. If the chip is indeed a Zilog S3F94C8 (or equivalent chip), then the ADC reference voltage is fixed on VCC (so no need to measure it).

However, VCC is all over the shop, since this clone is so poorly designed. It's very hard to tune the temperature properly. I'm seeing VCC voltage drops and noise, whenever the hand piece fan is running, so I suspect the transformer is simply not big enough to handle the load, which is probably why the designers choose to put the IC after a diode with another capacitor, causing the chip to run at 4.3V instead of 5V. Not that it helps, since the caps are shitty quality anyway. I tried swapping some of them, and got a more stable power rail, but could still not adjust the temperature properly, and I have just not worked on it since last time I posted.
I probably should have another look at it, since at the moment it's just sitting on the bench. :D

/Miwer
 


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