Youyue 858D+ some reverse engineering + custom firmware

[Carrington]

@ madworm: Good job. 
Have you thought about programming this reflow curve (or something similar)?

[madworm]

I'm not sure that it would be helpful. The air temperature (once outside the device) varies a lot, depending on nozzle size, air-speed, distance to board...

If you need / want that functionality, you'll have to code it yourself.

[Carrington]

I'm not sure that it would be helpful. The air temperature (once outside the device) varies a lot, depending on nozzle size, air-speed, distance to board...

Yes, that's right.

If you need / want that functionality, you'll have to code it yourself.

The truth is that my goal is very specific. I'm thinking about using two 858D + (one above and one below), to create similar conditions as an oven (a small oven).
Are all microcontroller pins used? Because a serial port could be a solution.

[madworm]

Code: [Select]

/*
 * PC5: FAN-speed (A5 in Arduino lingo) (OK)
 * PC3: TIP122.base --> FAN (OK)
 * PC2: fan-current-sense mod (OPTIONAL) - see Docs folder
 * PC0: ADC <-- amplif. thermo couple voltage (A0 in Arduino lingo) (OK)
 * #21: AREF <--- about 2.5V as analog reference for ADC
 * PB1: opto-triac driver !! THIS IS DANGEROUS TO USE !! (OK)
 *
 * PB0: 7-seg digit 0 (OK)
 * PB7: 7-seg digit 1 (OK)
 * PB6: 7-seg digit 2 (OK)
 *
 * PD0: 7-seg top (OK)
 * PD1: 7-seg bottom left (OK)
 * PD2: 7-seg bottom (OK)
 * PD3: 7-seg top left (OK)
 * PD4: 7-seg dot (OK)
 * PD5: 7-seg bottom right (OK)
 * PD6: 7-seg middle (OK)
 * PD7: 7-seg top right (OK)
 *
 * PB5: SW1 (button1) (OK)
 * PB2: SW2 (button2) (OK)
 * PB4: reed switch (wand craddle sensor) (OK)
 *
 */


[GiskardReventlov]

Atyue?

How about Gaoyue or is this old? Did this start the naming chain reaction or are the names randomized or just a mystery?

It's only an 858 not 858D

eBay auction: #131087676123

Are  these non-D units simpler and therefore less problematic?  Does anyone know how temp is controlled in these?

[tx8]

http://www.aliexpress.com/item/Free-shipping-BEST-858-BEST858-BEST-858-858-welding-station-rework-hot-air-gun-solder-Rework/546575498.html
I dont know, but there are several versions of that one, too. Maybe they are completely analog.  This one i found says 1600w others only 400w. Its a jungle out there. I think the youyue 858D+ is the best with madworms firmware no doubt. Cheers again for that!

[Carrington]

Are crap, but are cheap and easy to modify.
For example the NT F-204:



Not fun:



Funny:





I need another one below the board.

[GiskardReventlov]

Its a jungle out there.

It's a junk-le out there.

I think the youyue 858D+ is the best with madworms firmware no doubt.

I have been following this thread and I thought I read that you never know what's inside even though the name and model are the same.  I've seen a lot of W.E.P. for sale too. I guess it's a crap shoot.  Emphasis on crap.

[tx8]

I have been following this thread and I thought I read that you never know what's inside even though the name and model are the same.  I've seen a lot of W.E.P. for sale too. I guess it's a crap shoot.  Emphasis on crap.

As far as I read the Youyue 858D+ models are all the same technically. Or did i miss something? Build quality varies at least check for propper ground connection for all exposed metal parts.

[linux-works]

I have some interest in this thread.  in fact, I was planning on building my own PID controller for the hakko 936 series.

I recently bought some hot tweezers that are 936-style plugs and it would be great to have a dual display to show the set point and the current temp point.  I'd also like a safety auto-off timer and maybe some other features.

my first task would be to create a table of the resistance of the temperature sensor (or the voltage out, if its a thermocouple and an amp stage) so that I can display the 'oper' (current) value.  since this is currently a bang-bang thermostat, the 'admin' (set value) is nothing real or measured but just a reference that is used to stop sending current to the iron.  that can be done entirely in firmware.

I find it very useful to display both, the admin and the oper values; and so I'll probably use a small lcd or maybe dual led display rather than modifying the existing driver board in the base station.

[tx8]

I have some interest in this thread.  in fact, I was planning on building my own PID controller for the hakko 936 series.

I recently bought some hot tweezers that are 936-style plugs and it would be great to have a dual display to show the set point and the current temp point.  I'd also like a safety auto-off timer and maybe some other features.

http://makezine.com/2012/01/10/open-source-soldering-iron-driver/

too bad its in serbian... might be helpfull

[linux-works]

I'll give that a look.

the basics of heat control are not hard.  I wrote software to 'manage' my espresso machine and its the same exact concept, probably even most of the code can be re-used.

I'm not sure, yet, if the temp sensors in the tweezers and the 936 style iron are t-couples or something else.  I think its simple resistance but I will have to find out for sure.  if its a true t-couple, adafruit makes a nice amplifier/driver board that works a treat.  if its simple resistance, then I can read that pretty much directly with simple circuits.

the value is the user interface and features and I find off-the-shelf consumer grade irons to have really minimal user interfaces and feature sets.

[GiskardReventlov]

As far as I read the Youyue 858D+ models are all the same technically. Or did i miss something?

No I think I missed something, there was another model by atten I thought it was a youyue. Dave did a video on the atten. I don't know if he identified the mcu though.

[tx8]

Monkeh pointed that out already:

E: If the Youyue is meant to be the clone, it's significantly better built than the Atten.. No isolation slots, no attention to clearance, single-sided PCB with all the dodgy reverse soldering that implies, two 14-pin sockets used for the 28-pin micro, flux everywhere, damaged ground lead from poor stripping..

And of course a completely different (Holtek) micro.

some other guy reported he had mains voltage on the metal nozzle on his atten.

[tjb1]

So my WEP branded hot air station just died today and I was wondering if someone here could help me troubleshoot it.

I had finished using it and put the gun back into the holster and it did the normal cooldown and shut off routine.  Few minutes later I noticed the fan had come on but the screen was off(power to unit still on).  Removing gun and putting it back in does nothing, fan stays on but no heat when in holster or when removed from holster.  Screen does not come on at all.  If I shut unit off and turn back on, screen comes on real quick and goes back off and then fan comes on.

Using my E4, the first time I took it apart I noticed the big capacitor in the front of the picture was up at 114F.  Put it back together and turned it on again for a little while, turned off and took apart and seen the TIP122 transistor was up around 104F.  The regulator seems to get a little warm but I think that is to be expected.

Board picture - https://www.dropbox.com/s/tr38qt46xdvy74b/2014-04-12%2022.18.11.jpg



Thermal picture - https://www.dropbox.com/s/6mu0yq5gsdpy273/FLIR0067.jpg




And a video showing what it is doing

https://www.dropbox.com/s/h36domywr8syxzf/2014-04-12%2022.26.03.mp4

[tjb1]

Well after some poking around with the E4, I did find the issue.  Little ceramic capacitor had a baked top, I'm sure the issue is more than that but I found an axial with the same value and tossed it in and all is good for now.

[eldosergio]

Hello everybody, I recently bought a Baku 858D and found that, inside, it's like the one from Brainwash or Tjb1 (i.e. 20-pin micro, mine is completely black). The PCB is the same.
I would be interested in adapting this project to my station, as far as I've seen all schematics foresee the same blocks (not-inverting thermocouple amplifier built around OP07), linear regulation of fan voltage and feedback to uC, AC regulation by means of triac + opto 3020 or 3040), it should be simple by just using an adapter board for the uC (display connections still to be verified).
I've found that temperature regulation in my station is not that good. For example, setting a temperature of 350° C and an airflow in the upper part of the scale, looking inside the wand I see the heater glowing red, then the temperature decreases and it looks less bright, then it glows again. It stays hot for 1 second, then "less hot" for another second and it repeats.
Is this a common behaviour with factory firmware, also for Youye or Atten?
I'm a little worried that cycling temperature this way could lead to a premature death of heater...
For the moment I managed to reduce this behaviour by reducing the power to the heater. Basically I put a diode in series to heater with a 20k resistor in parallel to said diode (resistor was needed most probably because the opto needs it, I didn't investigate why without resistor it doesn't work). This way the maximum power to heater is 350W (instead of 700W), it's sufficient also at max airflow and the effect is to reduce temperature swing of the heater (still present, but at a lower degree).
Any plan to introduce a phase modulation of 230V to the heater instead of on/off control (would require an hardware mod)?

Thanks
Sergio

[madworm]

I'm certainly not going to touch any of the HV stuff in there. If it ain't broken, don't fix it.

[rob77]

very interresting thread and excellent job madworm !
i just wanted to suggest the proskit SS-969 - it's the same unit from outside, and it has a atmega8 inside - so you can mod the firmware easilly (you won't be surprised by a weird 20pin MCU while expecting an atmega)
on the other hand i have no need to mod my SS-969 - it works like a charm. and the build quality is simply excellent for a product which costs ~70Eur.

[GerdJ]

Hi there,
really nice work creating a custom firmware for the YouYue 858D+.

I own a Atten 858D+, which has a different board and mcu.
I found the schematics for the Atten 858D+ (don't know if they are 100% correct!), but I think it should not be a problem to change the mcu to a Atmega mcu like done for the YouYue with some sort of adapter board.

My question is, how to calibrate the device after changing the firmware. I guess that YouYue maybe has another temp-sensor values compared to the Atten. I need to know what value the sensor (resistance in ohm) will produce at a certain temperature. Or am I totally wrong and it's much easier?

Anyone can help?

[madworm]

You just need an external high-temperature thermometer to calibrate the temperature sensor. Many multimeters can connect to thermo-couples, which can do a couple of hundred °C.

It is not hard to make a table of raw ADC values vs. measured temperature. In case of the Youyue, the relationship was linear. Do a least-square fit on the data with a linear model (openoffice can do that), and you have your 2 parameters to translate between raw-ADC and temperature.

So... when you first upload your alpha-firmware, set the duty cycle for the heater to a safe level (e.g. 1% or so), let your firmware show the raw ADC value on the display and measure the air temperature at the nozzle with a thermo couple. Then increase the duty cycle carefully a bit to get a higher temperature and repeat the process for enough data points up to 500°C or so. As at this stage there cannot be any temperature regulation, make sure you have a very close watch on the heater and have the fan spin at maximum rpm. Once you have enough data points to calibrate the sensor, your next step should be implementing a fool-proof over-temperature shutdown. Once that works, do PID and user interface.

[Carrington]

You just need an external high-temperature thermometer to calibrate the temperature sensor. Many multimeters can connect to thermo-couples, which can do a couple of hundred °C.

It is not hard to make a table of raw ADC values vs. measured temperature. In case of the Youyue, the relationship was linear. Do a least-square fit on the data with a linear model (openoffice can do that), and you have your 2 parameters to translate between raw-ADC and temperature.

So... when you first upload your alpha-firmware, set the duty cycle for the heater to a safe level (e.g. 1% or so), let your firmware show the raw ADC value on the display and measure the air temperature at the nozzle with a thermo couple. Then increase the duty cycle carefully a bit to get a higher temperature and repeat the process for enough data points up to 500°C or so. As at this stage there cannot be any temperature regulation, make sure you have a very close watch on the heater and have the fan spin at maximum rpm. Once you have enough data points to calibrate the sensor, your next step should be implementing a fool-proof over-temperature shutdown. Once that works, do PID and user interface.

Linear? Sure?

And the cold junction? You have an error equivalent to the room temperature.

Look attached code (is not finished), I have tried several PID, but I can't get it work properly (without cheating). 
I attached the impulse response, but the heater is turned off after reach 450º C.
So I use the RC response as approach, because runing free it  probably reach over 600° C.
I think that is necessary a zero crossing detection. It need also different KP, KD and KI values, according to the air flow (different response).

I forgot to mention that I use only the AVR's internal reference and a gain of ~57, so the resolution is ~0.5ºC (theoretical, of course, and without the ADC errors).

The truth is that this stuff are boring me...


Another thing: The 858D uses a single resistor (to save two cents) for each digit (as current limiting). So, if you turn on several segments simultaneously the brightness varies. My code only allows one segment active at a time, for each digit.

[Carrington]

I need to know what value the sensor (resistance in ohm) will produce at a certain temperature.

uVolts, the temp. sensor is a thermocouple.

[madworm]

If you want to do a polynomial fit on the data, go ahead! If you want to fully characterize the system analytically and go crazy... your choice.

I just did a 2-point calibration for the readings and checked if the middle point is close enough, and that was the case. This is not a precision instrument that requires 0.5°C resolution, +-5°C is plenty good.

Sure, the fan-speed messes with the PID a bit, but you can find parameters that give overall satisfactory results applying the principle of trial and error. You do have to limit the I-term if you're far away from the target.

If your code is giving you a headache, you may want to look at mine. Don't re-invent the wheel. It works quite well.

[Carrington]

LOL...

You can say whatever the hell you want.

I attached a simplified version, only ON/OFF control. If someone wants to use it as a starting point, go ahead.

Cheers,
Carrington.