HeaterMeter Controller, with Wifi, and Electric Smoker (MES40) Mod in Detail

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So I'll try toggle some information about how I added heater meter control to my MES 40.

I ordered some five pin connectors from amazon.


happily these turned out to exactly match the connectors used to connect the bluetooth controller to the MES.

I also ordered an adjustable voltage divider though you could easily use fixed resistors as well.


This allowed me to reduce the heater meter fan control line to 3.3 volts (which is what comes from the controller board.

I also ordered a weatherproof ethernet pass through.


to connect the heatermeter control line to the MES.

I also bought a single throw dual pole toggle switch at my local home depot.

There is a small amount of soldering involved in this project. I also used liberal amounts of heat shrink tubing.

I started by butchering an ethernet cable and using just the blue (ground) and blue white (fan control signal) I soldered thereto the ground and VCC pins of the voltage divider. I also soldered another blue wire to the ground pin (to carry through to the MES) and another blue white to the output of the potentiometer as shown below


Now I started setting up the connectors. All the lines but the blue (signal) and white (signal ground) go through. The package comes with both male and female connectors so you can take one of each and solder together the black, greed and red wires. You can also solder together the white wires and solder in the blue wire from to potentiometer ground.


That's really all the soldering. Now you can attach the blue wire from the controller side of your go between cable to one pole of the switch and the output side to the center connector. The blue white wire from the output of the potentiometer goes to the other pole as shown below. Now you can select between on-board control and heater meter control.


Here' the final wired assembly, as you can see I put heat shrink everywhere.



I used a stepped drill bit to drill holes in the plastic controller cover for both the switch and the ethernet pass through. Here's the pass through side (I put it on the left)


Here's the switch side. There was plenty of room for the wiring.


Here's the assembled panel on the MES. I think it looks pretty clean. Well the smoker is dirty but the install looks nice.


I think theres room for something even nicer. You could take the 5 volt line from the heater meter controller and use that to automatically detect the heater meter connection and automatically switch to heater meter control. 
 
Hahahaha wow that is cool!

I can't wait to see it in action! :)

Oh by the way I blew one of my 15A quick bust glass fuses yesterday during a smoke.  I have a feeling it simply wore out or the controller box temp got too hot.  I replaced with another fuse, pulled the top off my controller box, and continued with no issue.  I also did about 8 pounds of smoked pork franks today for about a total of 6 hours of operation and no issue.

Just some info if you ever have an issue with a glass fuse busting :)
 
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Cooked a couple of small briskets on Sunday. Ran the whole thing through heatermeter on my phone and ipad. They came out really well.
 
 
Cooked a couple of small briskets on Sunday. Ran the whole thing through heatermeter on my phone and ipad. They came out really well.
Congrats on the successful cook!

How cool is the HeterMeter controller?

Also did any of my info on settings help out at all?  I am hoping my PID settings really help people get dialed in or start them off closely.  Also that freaking "Lid Open" feature is a pain.  I hope that my notes on fixing that setting for the MES use were useful.

Let me know if any of my info helped or was the opposite of helpful haha :)
 
I definitely used your PID settings and they held the temp really well. The iphone interface is pretty nice the heatermeter controller is the bomb and  works really well. I had a probe in each of the briskets and everything just worked. Maybe next time I'll use a port forwarding service so I can monitor when I am away from my wifi. Here's what the interface looks lie in portrait mode, in landscape it gives you the graphs.

 
 
I definitely used your PID settings and they held the temp really well. The iphone interface is pretty nice the heatermeter controller is the bomb and  works really well. I had a probe in each of the briskets and everything just worked. Maybe next time I'll use a port forwarding service so I can monitor when I am away from my wifi. Here's what the interface looks lie in portrait mode, in landscape it gives you the graphs.

That's awesome and the app looks good. The PitDroid app I use on my Android phone is a bit less flashy but basically the same thing.

Also, did you use a 3Amp Power Plug from the start?  That was an initial headache I ran into and discovered after some initial research on the RaspberryPi3 behavior.  Once I upgraded to the 3Amp power plug the reboot and such went away.

As for the port forwarding, I'm really thinking about that as well but I'm leery or opening up my router/network in any fasion.  I DO have a DNS name I just paid for while doing some Amazon Web Service certification training.  The networking lab has you buy a cheap one if you want to participate in the lab so I got one for like $10 or $11 for a year so I could just use that DNS for it.   I'm still debating but as for now my TP20 reaches all the way out to the pool so I have the long range alert covered.  

I'm not really sure I need the full internet access.  I don't like the idea of leaving the house with the MES going.  If it starts to burn down I would like to be a 10 second sprint away rather than a drive away lol.

Here soon I'll do a post with my convection fan mod.  I just need to do another test chicken smoke with the stock MES pan installed to see if it blocks the chicken from dripping on the heating element and then I think I am will have 100% of my kinks worked out.  Right now chicken juices are dripping directly onto my flipped heating element thereby preventing the smoker from getting to 325F quickly hahaha.  If I have that solved by simply adding the stock water pan back (empty of course) then I don't believe I'll be making anymore mods :D  
 
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Now that is cool. Seen a mod done to a Bradley. This is way more cooler. I'm glad nothing happened to this thread during the move to the new platform. Love the prices that you call out. Kinda gives a heads up for saving. How is your unit since then? I must say. Very cool.
 
Now that is cool. Seen a mod done to a Bradley. This is way more cooler. I'm glad nothing happened to this thread during the move to the new platform. Love the prices that you call out. Kinda gives a heads up for saving. How is your unit since then? I must say. Very cool.

Thanks I'm glad you like it and I agree it is pretty cool lol.

The HeaterMeter has been working with no issues. Now I just had an issue Thu night where my safety rollout limit switch was failing... while I had a brisket cooking! I had to remove the brisket cool everything off and make the repair. I got it all repaired in like 15 minutes and was back up and running. Thank goodness I had extra rollout limit switches and I made a panel to access it so I wouldn't need to pull the back off my MES to access it lol. :D
 
So I'll try toggle some information about how I added heater meter control to my MES 40.

Hey Monkey, and OP. Thanks for this info.

I just got my MES 30 at Walmart for $55 yesterday, and I see a heater meter in my future.

I completely agree that using the existing wiring and relay is the way to go, why reinvent the wheel? I would assume in the future when this relay dies, I can replace it with SSR.

All raspberry pi boards have several GPIO pins that output 3.3V. I would imagine they could be used to control the relay on the MES with very little change to the code.

Monkey, were you able to determine what the other pinouts on the 5 pin jst connector for the MES are for? What voltage does the standard controller run off of?

I'll be ordering my heater meter in the next few days most likely.
 
Hey Monkey, and OP. Thanks for this info.

I just got my MES 30 at Walmart for $55 yesterday, and I see a heater meter in my future.

I completely agree that using the existing wiring and relay is the way to go, why reinvent the wheel? I would assume in the future when this relay dies, I can replace it with SSR.

All raspberry pi boards have several GPIO pins that output 3.3V. I would imagine they could be used to control the relay on the MES with very little change to the code.

Monkey, were you able to determine what the other pinouts on the 5 pin jst connector for the MES are for? What voltage does the standard controller run off of?

I'll be ordering my heater meter in the next few days most likely.
Hi there and welcome!

Word to the wise get a 3 amp or better power plug/supply for the HeaterMeter. If you go with the documented 1 amp it will crash and reboot a lot on you when using Wifi. The Pi3 seems to get power hungry with some spikes and those spikes cause a reboot. A 3 amp plug resolves this. Best of luck :)
 
Hi there and welcome!

Word to the wise get a 3 amp or better power plug/supply for the HeaterMeter. If you go with the documented 1 amp it will crash and reboot a lot on you when using Wifi. The Pi3 seems to get power hungry with some spikes and those spikes cause a reboot. A 3 amp plug resolves this. Best of luck :)

I am going to probe some more into the wires that feed up into the stock controller. It's possible there is already a 12V source (although what amperage?).

Monkey already determined the wires that control the relay... the others are likely a VCC of either 12V or 5V or both and another ground wire.

That also means there is a transformer and rectifier built in, that could likely be changed out if needed to give a steady 12v 3amp source for the heater meter.

In my mind, running the whole thing off the main plug of the MES should be a primary goal.
 
I am going to probe some more into the wires that feed up into the stock controller. It's possible there is already a 12V source (although what amperage?).

Monkey already determined the wires that control the relay... the others are likely a VCC of either 12V or 5V or both and another ground wire.

That also means there is a transformer and rectifier built in, that could likely be changed out if needed to give a steady 12v 3amp source for the heater meter.

In my mind, running the whole thing off the main plug of the MES should be a primary goal.

Let us know what you find out.

Another less technical approach would be to just put a 12v 3amp plug down there in the chord or PCB compartment and wire a female end of a plug into the MES plug wiring and just plug the 12v plug into the wired in female plug.
Then you just run the 12v plug wire through the MES like the existing wiring and you are all set in a nice neat, clean fashion.
Well not as nice and neat as your approach to wire into the MES power but the next best thing :)
 
Do any of you gentlemen know if there is an option to add a fourth probe to the heater meter if you don't get the thermocouple? As my MES isn't going to see temps over 300'F, a thermocouple seems an overkill, but if its the only way to get 4 points of data, then so be it.

Also, looking at the schematic: http://capnbry.net/linkmeter/pcb/hm-4.2/HeaterMeterPi.png

The standard Heater Meter PCB has a MCP1700-33 voltage regulator at IC4, so 3.3V is already on the board. It should be pretty simple to add jumper to have the transistor that controls the blower fan trigger a 3.3V signal instead of 12V. In that case, no external voltage divider or resistors will be needed to control the stock relay.

Or, alternatively, another 3.3v voltage regulator could be used at the connector side connected to 12V and ground, and using one of the unused holes on the cat-5 connector. Then you would have both a switched 12V and 3.3V output. The voltage regulator could be attached to the bottom of the board.
 
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Looking at the power board on the bottom of my MES 30 sure enough there is a 12V AC transformer... but only rated at 250 ma. Not enough to power a heater meter when rectified. It gets dropped down to 5V with a voltage regulator and that is what controls the stock controller.
 

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Looking at the power board on the bottom of my MES 30 sure enough there is a 12V AC transformer... but only rated at 250 ma. Not enough to power a heater meter when rectified. It gets dropped down to 5V with a voltage regulator and that is what controls the stock controller.

That sucks. Thanks for doing the homework.
There may be a more elegant solution but for now all I can see is taking the power from the MES cord and running through a 3 amp 12V adapter/plug and run the wiring through the MES body up to the heater meater.

Does this sound about right?
 
That sucks. Thanks for doing the homework.
There may be a more elegant solution but for now all I can see is taking the power from the MES cord and running through a 3 amp 12V adapter/plug and run the wiring through the MES body up to the heater meater.

Does this sound about right?

It sure does. Still an elegant solution as there will be no external wires running and only 1 plug to the outlet.
 
It sure does. Still an elegant solution as there will be no external wires running and only 1 plug to the outlet.
If I did my setup again I think I would go that route rather than creating my big controller box.

I have a convection fan installed into my MES and wired up to be fed through my controller box. The variable controller doesn't give a fine grain enough control to really matter and I have learned that max speed on my fan is fine in every one of my applications so far so the variable speed idea is a moot point to begin with.

I would still wire in the convection fan BUT I wouldn't have built a big box with plugs and switches etc. I think I would have come up with a way to have just put everything (ssr, heat sink, 12v plug for PID, etc.) down in the compartment where the MES pcb is at (in the bottom of the MES) and then ran wiring elegantly from there with a switch up top. Switch would have been for off/fan only/HeaterMeter PID + heat + fan. When I cold smoke I don't need the PID or the Heat going, just the fan.

I could then have had the HeaterMeter PID controller rest on top of the smoker just like the MES controller does today.
Oh well, hind sight and all :)
 
I don't understand the role of the SSR. There is already a mechanical relay built in for the stock controller.

Does the heater meter cycle the heater element rapidly enough that you need to be worried about the built in relay blowing?
 
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