# Successful MES brain transplant!  Plug and Play replacement controller = Full  PID + Cellular contro



## tiros (Sep 6, 2017)

MyOvenScreen.png



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MyOvenHW.jpg



__ tiros
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My MES40 gen1 temps were allways a good 20 degrees low, oven could not make 275. I was tired of staying tethered to my smoker. I was tired of only having one meat probe. I decided to make a new controller, to replace the old controller completely. It is working and usable right now. I have smoked in excess of 200 lbs of food with it!

Features:
Full PID control with Autotune built in!! Holds within one or two degrees of setpoint.
Full wireless control from anywhwere through my Android device.
8 probe channels, more precise than Heatermeter, thermistor channels are fully buffered.
No modifications to the oven. Remove old controller, replace with this. Easy to switch back to stock.
No separate power supply. 
Exports charts and graphs to email.
Uses only about $20 in parts.

Does not require an SSR modification to achieve full PID Control. Just like in the original design, the power is regulated by relay on/off time. My code uses a special anti relay hammering algorithm I developed that insures the relay is not short cycled while still achieving near perfect temp control.

Not real expensive, but a local Rasberry Pi server is recommended somewhere in the home. The Raspi does not have anything to do with controlling the oven. It has no physical connection to the oven. It is used as a wireless bridge from the internet to the new controller.  An internet connected always on PC could also be used, but a Pi is cheaper and lower power.

I am using the excellent Thermoworks Pro-Series probes, SKU: #TX-1003X-AP for oven temp and SKU: #TX-1001X-OP for meats. Got them directly from Thermoworks, about $15 each.

In progress right now:
Use two of the 8 channels to buffer and read the built in MES oven and meat probes.
Select any channel as the oven control channel.
Get notification by text or email when a probe reaches set point. (No screenshot yet)

ToDo:
Create some kind of enclosure.

Probably won't generate much smoke when using the chip box. I use an Amazen. I might add some code to allow more temperature swings, (MES mode lol) which translates to more "on" time for the element.

Currently the project exists as a one off bread board. If there seems to be interest, I can lay it out on a pcb. Maybe sell some boards or a kit. I have the MES40 Gen1. From what I have seen, it should be very easy to port the design to another model.

I am trying to monitor the built in MES probes with two of the 8 available channels. I need the Stienharts for those. I have a curve for the meat probe that works ok. That one doesn't work for the oven. If I could remove the oven probe, I could characterize it or replace it. Doesn't seem to be a way to get behind it. It looks like maybe under one of the serial number plates in the back might expose it?


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## candurin (Sep 6, 2017)

Fantastic!  Well done.

And I was excited when I built a retropie.  This is much better than my Gen1 analog with Auber PnP PID.


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## redoctobyr (Sep 7, 2017)

Wow, Tiros, that is amazing! Well done!! 

Any further details that you chose to share would only help people, I'm sure. The idea of being able to buy a hardware kit is interesting. 

At some point I will likely do some more research on building a temp-logging device. But this is way cooler, also incorporating heater control. Awesome! 

When you say it replaces the controller, you mean is just Taps into the connector at the top of the smoker, rather than requiring "surgery" to tie directly to the heater element leads? If so, that's pretty slick. 

Again, great work, thanks for sharing! It's so cool to see what inventive, clever people can come up with.


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## dr k (Sep 7, 2017)

These Mes digital hacks are fun to read!

-Kurt


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## tiros (Sep 7, 2017)

RedOctobyr said:


> Wow, Tiros, that is amazing! Well done!!
> 
> Any further details that you chose to share would only help people, I'm sure. The idea of being able to buy a hardware kit is interesting.
> 
> ...


Thanks!

Yes it plugs directly on to the existing connector on top. The old controller is removed and not used anymore.

There is no surgery of wiring. On that subject, from what I have read here, there are many unnecessary surgeries being performed! It turns out all you need to do to use the other PID box solutions I have seen here is simply "hot" the relay on all the time. A 1k ohm resistor from +5 volt to the relay pin will leave the relay on whenever the unit is plugged in. On my MES40 gen1 this is would be the red wire on pin #1, and the blue wire on pin #4 of the control box. Remove the control, add resistor to the ovens wires and your done. Since the relay contacts are now "on" all the time, they don't wear out. Then you just plug it in to your PID box.  No need to drill anything.  :)

In my solution that blue wire is controlled by the microprocessor that is performing the PID calculations, monitoring temps, and talking to the phone. There is plenty of power right from the old controllers connection on top of the oven, I don't need a separate power supply. Since I am using the relay to control the power/temperature I don't need an SSD mod either. I was very careful about the frequency of relay cycling to not hurt the relay. Masterbuilt does it this way. I just control that blue wire a hella lot better than they do :P

If there is enough interest I can lay out a PCB board. Maybe do something like the Heatermeter does? A board, a kit, assembled? Also need to decide about through hole or SMT layout. There is really not many parts.

I have seen some other MES control boards, and they all look very similar in the way I would need to tie in. If I had photo of your models control boards PCB side, I could add a connector for it.


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## tallbm (Sep 7, 2017)

Man that is cool!

What are your plans for creating the project box/enclosure?  

If I had mine to do all over again I might think of trying to talk to someone to have it custom designed and 3D printed with a better grounding design in mind.  I don't really ever deal with hardware or electronics in this manner so my HeaterMeter setup and my controller box job were basically my best stab at creating something functionally solid.

Great job and it is cool to see it turning out well.  I'm sure it is exciting to see your hard work pay off because I know it isn't a simple job :)


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## Rings Я Us (Sep 7, 2017)

Pretty sweet..


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## dr k (Sep 8, 2017)

Tiros said:


> Thanks!
> 
> Yes it plugs directly on to the existing connector on top. The old controller is removed and not used anymore.
> 
> ...


I enlarged the bottom component access pic that TallBM put up on the Gen 1 40 that I have that has the riveted plate over it and was wondering when the relay, transformer or any part of the circuit board fails how do we get those out like those that have screws securing the plate?  I haven't seen the Gen 2 or 2.5 so I don't know if there are screws in the circuit board to take out to replace the board.  Since the resistor on your custom top controller modifies MB"s relay then getting the whole replacement board from MB would be good since your design involves their relay.  So my main question is would your controller be best used on the Gen 2 or 2.5 user friendly replaceable circuit board vs. the Gen 1?

-Kurt


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## tiros (Sep 8, 2017)

Kurt,

I am not sure I understand maybe I confused things in my explanation. I clarify:

There are two boards in each smoker, the power board, located on the bottom and the control board located on the top. My project replaces completely the top control board. The lower board is not affected in any way. The lower board is the ovens +5 volt power supply and the element control relay. It has some wiring that connects it the top control board. The relay on the power board connects to the control board up top by a blue wire. It also sends up +5 volts by the red wire, and ground on the white one. My control board then can control the relay (by blue wire) to provide heat when it needs to (The PID inside my projects CPU calculates how long to put it on based on temps). There is also a yellow wire for the oven light control coming from down there, so I can control the oven light as well :)

So for my MES-Gen1, I remove the two screws that hold the LED control board on top. Disconnect the 5 pin white plug from it, then connect the plug remaining on the oven to my board. That's it! That's all! Take a look at the photo in my first post, That blue colored board on top of my grill is the ONLY mod. If you look carefully you can see it plugged into the factory wiring harness. You don't cut or add any wires. You can put the old one back any time.

I only mentioned the lower board before to explain how to hot wire the oven to be on all the time for some people who are using PIDs from like Amazon or Ebay. It had nothing to do with my project at all.

Tall:

Thanks. Your build inspired me to try this.

As for the case, I don't know what to do. Currently I flip a rectangular plastic container on top of the blue board, like a tent. :)

I don't want the probe jacks to get wet if it rains. They need to be under some kind of a "roof" in the enclosure I think.

I was also thinking that it would be nice to solder those jacks right to PCB, maybe on the edge, then abut the PCB to case somehow so they can poke through.

I am wide open for any Ideas you have!


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## tallbm (Sep 8, 2017)

Tiros said:


> Tall:
> 
> Thanks. Your build inspired me to try this.
> 
> ...


I'm glad my little project gave you some inspiration.  You have definitely done some amazing work.

Your idea about the jacks is exactly what the HeaterMeter does.  It works well for them so I don't see any drawbacks for you to go that route.

As for the cover you are using, I totally get it.  After building my heavy duty enclosure I wish I would have had a plastic/metal combo peg board I could have zip tied everything to and grounded against as needed.  Then just covered it like you are doing or just put it in a big simple plastic enclosure.  Plastic is soo much easier to work with then steel.

With my all steel enclosure/project box I keep the lid like half off so the heat can escape.  I also have it sitting on plastic legs to elevate and get air under it.  

I went with what I could find but I kind of wish I went with a simpler enclosure and just rigged the peg board idea up somehow.


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## dr k (Sep 9, 2017)

Tiros said:


> Kurt,
> 
> I am not sure I understand maybe I confused things in my explanation. I clarify:
> 
> ...


I'm assuming the relay and voltage regulator or what ever your using at the lower PCB is attached as one piece being the PCB.  According to MB the lower PCB in the Gen 1 40 is not serviceable so when it fails the smoker is a goner so they riveted the access plate on.  It's like MB built the smoker around the Gen 1 PCB.  The Gen 2 and 2.5 I believe have all end user accessible plates to the PCB's that are replaceable so the plates have screws.  So when the Gen 1 PCB fails you may be able to hack that board whereby the Gen 2 or 2.5 owners can just get a new PCB from MB. That's why I was wondering if your controller is best used on Gen 2 or 2.5.  Us novices that can solder and terminate wires but can't hack circuit boards when they fail would be stuck with your fantastic top controller on the Gen 1 when the PCB fails. So I was wondering for the long run with the Gen 1 do TallBM's PCB bypass with a plug and play PID and do your top controller plug and play on the Gen 2 and 2.5.  I hope this helps.  TallBM may chime in if I'm way off.  He has crawled around inside a Gen 1 and 2 as well.    

-Kurt


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## bbqwillie (Sep 9, 2017)

Tidiest solution I've seen yet. Well Done!


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## tallbm (Sep 9, 2017)

Dr K said:


> I'm assuming the relay and voltage regulator or what ever your using at the lower PCB is attached as one piece being the PCB.  According to MB the lower PCB in the Gen 1 40 is not serviceable so when it fails the smoker is a goner so they riveted the access plate on.  It's like MB built the smoker around the Gen 1 PCB.  The Gen 2 and 2.5 I believe have all end user accessible plates to the PCB's that are replaceable so the plates have screws.  So when the Gen 1 PCB fails you may be able to hack that board whereby the Gen 2 or 2.5 owners can just get a new PCB from MB. That's why I was wondering if your controller is best used on Gen 2 or 2.5.  Us novices that can solder and terminate wires but can't hack circuit boards when they fail would be stuck with your fantastic top controller on the Gen 1 when the PCB fails. So I was wondering for the long run with the Gen 1 do TallBM's PCB bypass with a plug and play PID and do your top controller plug and play on the Gen 2 and 2.5.  I hope this helps.  TallBM may chime in if I'm way off.  He has crawled around inside a Gen 1 and 2 as well.
> 
> -Kurt


Kurt I think you are about correct in your thinking.  

If we think of the MES PCB in simple terms it does two things:

Feed Power to the controller and to the MES heating element
Get told by the MES controller WHEN to feed power on/off to the MES heating element
Tiros' board is basically a better version of the MES controller on top so if the bottom PCB fails on a Gen 1 then I believe Tiros' controller would suffer the same fate as the standard MES controller.  Tiros, please correct me if I am wrong at this point.

HOWEVER, with Tiros' board I think a Gen 1 PCB failure could be handled more easily.  It would still take some rewiring to:

Wire power to Tiros' board
Add into the MES+Tiros' board wiring/electrical circuit a new Relay (theoretically assuming the one on the Gen 1 PCB is shot at this point) to control on/off of power to MES heating element
New Relay has hot/power wire wired to it and to the MES heating element (preferably with rollout switch still in the loop); relay can  now cut on/off power to heating element
New Relay has control signal wired to it from Tiro's board; relay can now receive control signal to switch power on/off according to Tiros' board control behavior

Unless I have misunderstood something to this point I think that would be all that is needed to use Tiros' board should the Gen 1 PCB fail or should someone want to completely bypass the MES PCB all together.  Now I didn't cover any details an which relays would work, if any working relays really exists, how the additional wiring and relay would be wired up and housed/enclosed, etc.

This is all just conceptual and logical brainstorming and the details would come once these ideas are vetted.

Man this nerdy stuff is kind of fun to think and talk about hahaha.

Tiros please feel free to correct anything I may have misstated or anything that is just plan incorrect/inaccurate.  I don't want to put any potentially confusing or bad information out into the world if I can avoid it :)


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## tiros (Sep 9, 2017)

Ahh! now I understand the concern.

I was not aware the lower pcb was not serviceable. I just checked mine, and there are rivets not screws :( 

However I do have a drill :) The question is this: Can that lower PCB be removed at all?

If so, it can be repaired. It is a very simple circuit. Another option might be to use the board used to repair the other style. Another option, duplicate that board.

Tall:

In this photo:

http://www.smokingmeatforums.com/t/63863/masterbuilt-not-working-properly/160#post_1676242

There seems to be two lower boards. The yellow has screws, the white does not. What are these from?

I'm sure that yellow board can replace the white one. If not directly, with some small modification,

My control board needs only 3 things from any host to operate, +5, Gnd, and a control line for the element. The temperature sensor is supplied by a probe. So yes the board could drive a relay box, plugged in to a rewired oven. It could drive a kitchen oven. It could drive a toaster oven. It could drive a sous vide heating element. It drive run any kind of heater if there is a way to control the power element.

I built this for Gen1 only because that's what I have. The project hardware would be basically the same for any heating device I want to control. Some small tweaks to the code would allow it to work on really any kind of heater. I suspect MB uses the same config for all their units and I would likely be able to find the 3 connection points I need for any model they make without any change to my hardware. These 3 points are easy to find. I could probably find them by looking at a photo of the PCB solder side, if anyone cares to post a pic.


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## tallbm (Sep 9, 2017)

Tiros said:


> Tall:
> 
> In this photo:
> 
> ...


In that post I simply located 2 different pictures of the MES PCB.  They are from different generations of the MES.  They were not my direct images.  I don't have real good direct images other then some of the ones I used in my rewire post.

I agree that the boards are very possibly interchangeable between gen 1 and gen 2 however we all know that they have different controllers and physical designs so the controller algorithms/code may be a bit different.  I'm not sure that would have too much affect on the PCB unless they change control signal strength or something like that.  I'm not one for that much guess work and would only consider checking it out if I had the spare parts laying around.

I do wonder how much extra space would be down in that compartment if the board was removed.  I wonder because if the 25A SSR and heat sick could fit down there then that would be awesome for rewire jobs and could eliminate the need of any project box if using the HeaterMeter or some kind of simple PID enclosure should someone want to rewire.


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## muddydogs (Jan 9, 2018)

Tiros
Have you done anything else on this since your last posting? I'm interested in upgrading my MES 40" gen 2 temp control and have been looking at plug and play PID's then I ran across this post and am interested in your set up.

Also interested in how you talked about adding a resistor to the wiring to keep the relay on so the smoker can be plugged into a plug and play PID with no surgery, not sure I understand it all as I know enough about this kind of stuff to reek havoc and make lots of bad smoke come out of things.


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## Telemachus (Jan 13, 2018)

His adding the resister is basically just turning the standard (not SSR) relay on all the time.  Then you could wire in an SSR that is controlled by your PID.

Tiros, what microcontroller did you use?  Would you be willing to share your schematics and code?

What I like best is the 5V VCC, meaning no other power adapter is needed.


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## tiros (Jan 15, 2018)

I have the circuit mostly laid out on a PCB, but I haven't had any fabricated yet. There didn't seem to be too much interest. I might put it up on Github, but it seems like not too many smoking meat guys are into coding. My first idea was to make a kit.

From what I have seen since I designed it, it can probably work with most any of the MES electrics with digital controls. I am using an esp8266 wifi module, some op amps, and a 12 bit Microchip ADC. The PID is implemented within the microcontroller (Thanks to ...Brett Beauregard).


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## muddydogs (Jan 15, 2018)

I've looked into building a PID a couple times. I have thought about a PID to use with my lead pot while casting bullets a few years ago and now to use on the smoker but knowing how these projects go, my lack of knowledge, and not being able to get into learning like I do on other things I just decided to purchase the Auber PID. At $150 it probably saved me $200 as most of my projects tend to get carried away. The Auber works great and holds my temp within a couple degrees without the over and under run swings.
I thought it would be nice to have the temp probes on the smoker still work as well as the light but I have found that my Morpilot 6 probe thermometer takes care of any smoker temps I need. Seems a shame that I purchased a new MES just to do away with the controls and hook up a PID but my setup is running great and working like I want.


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## daveomak (Jan 15, 2018)

Great Thread Tiros !!!!  You are really helping out the younger generation to retrofit their smokers...

Iffin I were 30 years younger, I would dive right in...  Thanks for your brain power...


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## Telemachus (Jan 15, 2018)

tiros said:


> I have the circuit mostly laid out on a PCB, but I haven't had any fabricated yet. There didn't seem to be too much interest. I might put it up on Github, but it seems like not too many smoking meat guys are into coding. My first idea was to make a kit.
> 
> From what I have seen since I designed it, it can probably work with most any of the MES electrics with digital controls. I am using an esp8266 wifi module, some op amps, and a 12 bit Microchip ADC. The PID is implemented within the microcontroller (Thanks to ...Brett Beauregard).



I have etched many a circuit board.  I could help with the Eagle layout if you are interested.

Do you use Assemblar with the microchip?  I have experience with JAL and C as well. 

I am a little suprised by the lack of interest here... maybe just not the right forum, LOL.

I was going to go the heater meter route, but I don't really think we need 12V of power nor a raspberry pi with the cheap esp8226 modules available... some even have the uC built into them with arduino sketch ability:


If you do get the GitHub going, please let me know.


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## Desjardo (Jun 18, 2018)

Hey guys.

I am writing code this week as well, same issue - dead mes 30.

I plan on using Blynk to control it.

Any chance you would share code to date?


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## Desjardo (Jun 18, 2018)

I have everything here already and will probably have it coded and running by weekend if you want to work together.


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## tiros (Jul 10, 2018)

Did you get it up and working?
Blynk is a nice platform. It makes the GUI development a snap. The real work is the rest of it ;)


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## Ben58 (Aug 6, 2018)

tiros

I am not a programmer by any means, but did you look at this: https://github.com/vitotai/BrewPiLess
There are a couple of people at Homebrewtalk who have done a lot of work that may help expand on what you are doing here, especially not needing a RPI.


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## drawz (May 25, 2020)

tiros
 I registered just to say I would buy this in a heartbeat as a kit or complete unit. You could even offer an upgraded model with an LCD/OLED display and a couple buttons so it could be used without a phone and/or wifi. Seems like a lot of people are buying more expensive PID controllers that require more modding. If this were available, it would be a no-brainer purchase for any MES in the know (and an alternative repair option when stock controllers die).

If you've decided for sure not to pursue offering a product, it sure would be nice to see this on GitHub or elsewhere so we can make our own! :)



tiros said:


> MyOvenScreen.png
> 
> 
> 
> ...


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## Hog (Jun 9, 2020)

tiros said:


> Kurt,
> 
> I am not sure I understand maybe I confused things in my explanation. I clarify:
> 
> ...





tiros said:


> MyOvenScreen.png
> 
> 
> 
> ...


I need electronically smart guys oppinions...

I got this idea from ya'll so here goes. I bought an Ink Bird 
	

		
			
		

		
	







	

		
			
		

		
	
ITC-1000F to control the heat in my electric Pt Boss smoker. Then I got online to get ideas for parts and came up with a fully functioning thermo-regulator that looks pretty cool. Problem is I didn't review the details enough to know that the Temperture Set Value -50~210 °F and of course the avg temp in the smoker runs higher than that. My question is can I just switch the temperature sensor out with the one in the smoker to change the Temp Set Value higher?


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## dr k (Jun 9, 2020)

Hog said:


> I need electronically smart guys oppinions...
> 
> I got this idea from ya'll so here goes. I bought an Ink Bird
> 
> ...


I don't know.  I can use a multi meter to figure stuff out but not code or build PCBs. In the description of the controller and sensor the sensor may have a different range than -50~210. The display may be limited to -50~210 so even if the pit boss sensor is compatible the controller may not go higher than 210.


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## drewb0y (Jul 5, 2020)

drawz said:


> tiros
> I registered just to say I would buy this in a heartbeat as a kit or complete unit. You could even offer an upgraded model with an LCD/OLED display and a couple buttons so it could be used without a phone and/or wifi. Seems like a lot of people are buying more expensive PID controllers that require more modding. If this were available, it would be a no-brainer purchase for any MES in the know (and an alternative repair option when stock controllers die).
> 
> If you've decided for sure not to pursue offering a product, it sure would be nice to see this on GitHub or elsewhere so we can make our own! :)


I second this. If you could post a schematic and the code at least that would be awesome.


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## TheEyeTGuy (Jul 13, 2020)

Agreed. Schematic and code would be great!


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## drewb0y (Jul 14, 2020)

TheEyeTGuy said:


> Agreed. Schematic and code would be great!


It looks like the original poster has not been around in a while. Last post was end of January.


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## TheEyeTGuy (Jul 14, 2020)

drewb0y said:


> It looks like the original poster has not been around in a while. Last post was end of January.


That's an absolute shame.


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## tallbm (Jul 14, 2020)

Hog said:


> I need electronically smart guys oppinions...
> 
> I got this idea from ya'll so here goes. I bought an Ink Bird
> 
> ...



Hi there and welcome!

I think the unit may not be able to display or handle signal to indicate above 210F.
It sucks but for about $40-50 I bet you could buy a different PID and an SSR (if u are not using one) and just replace the PID you have and u should be ready to rock and roll.  You can always use this unit for Sous Vide cooking or beer brewing if u do either of those hobbies.


I would also buy a different probe that was 6ft long and I'm partial to the ones with an aligator clip so u can move it around easily for more accurate temp readings not these wall mount types.

I hope this info helps :)


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## rick123 (Oct 13, 2020)

tiros
   I know this is an old thread but I'm working on a project very similar to yours based on an esp8266.  I may have wasted some effort though after reading through this thread. 

I am using 3 MAX31850K thermocouple amplifiers to read 3 probes currently.  I went this route both for accuracy and because I could not find anything solid on how to read something like a Thermoworks thermistor probe like you seam to be using.   *Could you explain how you are reading the Thermoworks probes accurately and how you calibrated them? *   Essentially, it comes down to cost.  The thermocouple route was easy and accurate but is much more expensive. 

I also built my own relay control board using an OMRON electromechanical relay driven by 5v signal.  I had to use an NPN transistor to control the 5v signal of course from 3.3v .  I was originally going to do a SSR like others have but was concerned about heat build up as I have seen some pictures of these things melted . I was happy to see the existing relay on the MES is driven with 3.3v signal and may now simply mount my PCB inside the existing front panel of my Gen 2.5 MES. It looks like I even have room for the MAX31850K boards and sockets the the K Type probes. Which leads to my second question. *Since you did your MOD, have you had any issues with the original MES relay?*


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## jr_ece (Mar 2, 2021)

tiros said:


> The relay on the power board connects to the control board up top by a *blue *wire. It also sends up +5 volts by the *red *wire, and ground on the *white *one. My control board then can control the relay (by blue wire) to provide heat when it needs to (The PID inside my projects CPU calculates how long to put it on based on temps). There is also a *yellow *wire for the oven light control coming from down there, so I can control the oven light as well :)



Do you know the purpose of the black wire? I uncovered the power supply board under my smoker and found the black wire is labeled STOVE-T.

Is that STOVE Thermostat or Temperature??

It is also routed to the 2 pin header that's next to the 5 pin along with +5V.


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## jr_ece (Mar 20, 2021)

I wanted to follow up with an answer for anyone following this thread. The STOVE-T has 5V applied by the power board (shown above) that then runs through the thermostat and finally routed up to the control panel where it monitors this signal for open/close. From a quick test, the control panel beeps and kicks off the heating element relay when 5V is present indicating the thermostat closed due to an overheating condition. You can see the 2 pin header that runs out to the thermostat. By looking at the back of the power board one can see the STOVE-T and +5V signals (shown in pic above) are simply routed from/to the 5 pin header that routes to the control panel.

Hope this helps someone.


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## MM2021 (May 24, 2021)

Great thread. Thanks 

 tiros
 , 
J
 jr_ece
, and others.

I've been trying to find the pinouts in order to use a 4-pin controller on a 5(+2) pin smoker. I figured out pins 1 (+5V), 3 (gnd), and 4 (element relay), and they are the same on both 4 and 5-pin connectors. When I connect pin 2, I get ERR1, so that must be different on the 4-pin system.

Putting +5V on Pin 5 turns on the light (via a relay).

The controller also gets a temperature reading with only Pin 1 and 3 connected, which is a little confusing. I wonder if someone can explain? The sensor seems to be malfunctioning and I'd like to wire in something else.

I might just build my own - I've got a simple Arduino controller running now using a thermocouple + MAX6675 board. The tricky part is wiring up a display + an input mechanism so I can check the temperature and change setpoint.


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## jr_ece (May 27, 2021)

MM2021,
From my research I believe the 5 position connector numbering is reversed from how you've referenced them. I know it really doesn't matter for our discussion, but just wanted to be accurate to the original design in case others catch up with our dialog.

If I'm right...

Controller connectors
CN2
5 --  +5V (red wire)
4 --  STOVE-T  (back wall temp sensor?); causes err if controller gets +5V on this input, probably due to this being max temp?
3 --  GND
2 --  HEAT  (+5V from controller closes relay on power board, turns on 120VAC element)
1 --  LIGHT (+5V from controller closes relay on power board, turns on 120VAC light)

CN3
2 --  +5V (out to meat probe)
1 --  AD (meat probe return input to micro controller)

If the 4 pin controller you are using has a LIGHT control button then the only remaining (missing) signal seems to be STOVE-T.  In this case there is nothing to do with this signal in relation to the controller, but you could still monitor with your own circuit (buzzer, LED, etc).


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## jr_ece (May 29, 2021)

dr k said:


> I'm assuming the relay and voltage regulator or what ever your using at the lower PCB is attached as one piece being the PCB.  According to MB the lower PCB in the Gen 1 40 is not serviceable so when it fails the smoker is a goner so they riveted the access plate on.  It's like MB built the smoker around the Gen 1 PCB.  The Gen 2 and 2.5 I believe have all end user accessible plates to the PCB's that are replaceable so the plates have screws.  So when the Gen 1 PCB fails you may be able to hack that board whereby the Gen 2 or 2.5 owners can just get a new PCB from MB. That's why I was wondering if your controller is best used on Gen 2 or 2.5.  Us novices that can solder and terminate wires but can't hack circuit boards when they fail would be stuck with your fantastic top controller on the Gen 1 when the PCB fails. So I was wondering for the long run with the Gen 1 do TallBM's PCB bypass with a plug and play PID and do your top controller plug and play on the Gen 2 and 2.5.  I hope this helps.  TallBM may chime in if I'm way off.  He has crawled around inside a Gen 1 and 2 as well.
> 
> -Kurt



Kurt,
You are correct that the Gen 1 Power Board in the bottom is really meant to be permanent with rivets holding the cover in place. My Power Board failed shorted and pushed the smoker to over 300 deg F before I realized it. I drilled the rivets, cut through the white rubber type coating, and removed it. Sadly, the 5 pin (to controller on top) and 2 pin (thermostat) connectors have their pins soldered to the PCB. I desoldered them, troubleshot the board and replaced a couple of components to return it to service. I also purchased mating Molex connectors and pins and added  headers and connector plugs so my Gen 1 is now serviceable. Upon working through all of this I believe that I can now purchase one of the newer serviceable Power Boards if the current board fails beyond repair (e.g., transformer). Point is, with a little work and the addition of 2 plug connectors the Gen 1 can be made serviceable. The hardest part is removing the white rubbery coating without damaging the PCB for the component repairs. note, I used a paint can opener to get under the edge of the PCB to pull it out of the cavity. As for the cover, I was originally thinking I would use screws or small fasteners to reinstall. I ended up using "baling wire" to loop through several of the mounting holes and then crossing over the middle back to the beginning of the wire. This allowed for using Lineman's pliers to put a good twist on the wire ends and cinch down the cover.


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## jr_ece (May 30, 2021)

tiros said:


> Ahh! now I understand the concern.
> 
> I was not aware the lower pcb was not serviceable. I just checked mine, and there are rivets not screws :(
> 
> ...



Very doable. See my previous post where I mention Gen 1 Power Board removal.


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## MM2021 (May 30, 2021)

J
 jr_ece
 thanks for clarifying the order.

The 4 pin controller has no LIGHT button.

I'm still trying to get my head around the STOVE-T signal. When you say thermostat above,  do you mean the (high temp cut-off) thermal switch? And by probe, do you mean the temp sensor on the back wall, or the meat probe (my smoker has both). I read somewhere that the power to the element was wired through that switch, but maybe it's different on this model?

It's still not clear to me how controller gets the temperature reading from the temp probe on the back wall.

I made my own simple controller with an Arduino and a thermocouple/max6675 board. No PID control, I need a bit of fluctuation to get smoke.


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## jr_ece (May 30, 2021)

MM2021 said:


> J
> jr_ece
> thanks for clarifying the order.
> 
> ...



MM2021,
Ah, so the light is the missing line.

Yes, STOVE-T is the label on the Power Board (see one of my post above for pic) that runs through out and through the high temp cut-off. I've had both the Power Board and Controller on the bench to troubleshoot. It's a 5V signal that is sent through the cut off and then to the control board from what I could determine.

My unit also has the temperature sensor on the back wall and meat probe hanging inside. I've done nothing with the meat probe to this point since I have a Maverick 4 probe unit to measure temps. It's a good question. There are few options here it seems, but I believe the 2 wire connector would have to be the back wall sensor although I have not confirmed it.


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## MM2021 (May 30, 2021)

The two wire connector is from the meat probe. I pulled it out so I could install my own sensor inside the smoker. I may switch back to using the probe on the back wall if I can figure out how to read it.


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## jr_ece (May 30, 2021)

MM2021 said:


> The two wire connector is from the meat probe. I pulled it out so I could install my own sensor inside the smoker. I may switch back to using the probe on the back wall if I can figure out how to read it.



Interesting. I'll have to look at the info I captured for my smoker to see if I can figure out where the back wall temp sensor is tied in. With you confirming the 2 wire is the meat probe then STOVE-T would have to be the input to the controller, right?

Hmm. This would also mean that my thermostat has also failed shorted since it went well over 300 degs when my Power Board failed. Will need to do some further testing and tracing signals now that is appears I missed this when repairing the Power Board.


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## jr_ece (May 30, 2021)

jr_ece said:


> I wanted to follow up with an answer for anyone following this thread. The STOVE-T has 5V applied by the power board (shown above) that then runs through the thermostat and finally routed up to the control panel where it monitors this signal for open/close. From a quick test, the control panel beeps and kicks off the heating element relay when 5V is present indicating the thermostat closed due to an overheating condition. You can see the 2 pin header that runs out to the thermostat. By looking at the back of the power board one can see the STOVE-T and +5V signals (shown in pic above) are simply routed from/to the 5 pin header that routes to the control panel.
> 
> Hope this helps someone.



Quick update. Based on MM2021s work, my earlier post is not accurate at least for his unit which I believe is very close to mine except no light in his model. So, in this case the thermostat must be wired inline to the AC line running to the heating element. I don't recall why but originally thought this was not the case with my unit. It makes sense now that it must be that way as others confirmed for similar models.


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## MM2021 (May 30, 2021)

Actually I've got a mismatch of parts: the smoker itself has five + two pins. The original controller failed and I ended up with four pin controller that I haven't figured out how to connect.


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## jr_ece (May 30, 2021)

MM2021 said:


> Actually I've got a mismatch of parts: the smoker itself has five + two pins. The original controller failed and I ended up with four pin controller that I haven't figured out how to connect.



I probably didn't state things as clearly as I should have, but mainly wanted to correct my post so I don't trip someone in the future.


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## jr_ece (May 30, 2021)

MM2021 said:


> J
> jr_ece
> thanks for clarifying the order.
> I made my own simple controller with an Arduino and a thermocouple/max6675 board. No PID control, I need a bit of fluctuation to get smoke.



I am really thinking about putting together an Arduino controller or following Tiros Esp8266 micro controller setup. I've also thought about looking into a PID (Inkbird on Amazon?) that would work with the built in Power Board. But, if it takes circuitry to make it work with everything then I might as well go the custom controller route and keep it low cost.

This is mainly due to the display failing on my controller. I can count button pushes/beeps and get close to what I want, but it gets old after awhile.


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## jr_ece (Jun 10, 2021)

MM2021 said:


> Actually I've got a mismatch of parts: the smoker itself has five + two pins. The original controller failed and I ended up with four pin controller that I haven't figured out how to connect.



Based on what I learned from a power board that mates with a 4 pin controller the pin ordering is the same minus the light signal. This could mean the actual pin numbers are renumbered from my 5 pin controller.  Regardless, here are how the pins are labeled and ordered on the power board:

*Power Board* connectors
4 pin connector - connects to controller
-- +5V (to controller)
-- TEMP (back wall temp probe -- sends varying amount of voltage to controller based on temperature?)
-- GND (to controller)
-- HEAT (+5V from controller closes relay on power board, turns on 120VAC element)

2 pin connector - connects to back wall temperature probe <-- concluded in thread above
-- TEMP (back wall temp probe -- returns varying amount of voltage to power board based on temperature?)
-- +5V (out to back wall temp probe)

As mentioned previously, the power board (the copper trace can be seen) simply ties TEMP to TEMP and +5V to +5V between the 2 pin connector and 5 pin connector on the 5 pin power board. This is assumed to be the same for the 4 pin since they are nearly identical designs.

NOTE:  My assumption for the back wall temp probe (or sensor) is based on our discussion above that TEMP (or STOVE-T on 5 pin) is the back wall temperature probe (not the AC thermal cutoff switch). I am going to see if I can make time to characterize this signal a bit while in operation at different temperatures.

Conclusion, I think you can wire the 4 pins directly to the the 5 pin connector (minus light signal) as long as the back wall temp probes are the same specs or at least very close.


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