Setting up my HeaterMeter - battery power and headless


 
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AndyR

TVWBB Member
This is my first post here so please be gentle :) I've lurked around this board for a while, but never had anything useful to contribute. I have a WSM 22.5 that I've owned for 5 years or so and it's served me well. Mostly well. Lots of sleepless nights waiting to check the fire or waiting for the wireless temp probe to wake me up because it lost its signal again. It's time to build a Heatermeter, but with a twist. I want to operate it completely standalone, as in no buttons or LCD, all wifi controlled, and all battery power.

I did some math (and guesswork/Google) and ended up buying a 18ah/12v sealed lead acid battery. It will be secured in the bottom of a small plastic ammo "can", where I will also mount the electronics and probably create a small compartment to store the probes when not in use. I wanted something that will run all night, at least, unattended, but also in almost any weather. It was -14F last night and windy, sometimes it rains, and so on. A self-contained Heatermeter is the goal. I am starting off using DavidNP's Espress wifi code to get it up and running and do some tuning (and make a brisket). I will probably end up making some code changes to add a battery meter and outside air temp, small stuff like that. I'm new to Arduino, but I've spent many hours programming PID stuff on AVRs (C, no Arduino), so I don't expect too much problem getting it going. I considered buying a used car battery jump starter, but all the ones I looked at were just traaaaaashed. If I would have found a decent one that would have worked out perfectly.

I have also started making an air burner from 3/4 copper pipe. Instead of soldering it all I am TIG welding it due to the heat. I practiced my autogenous copper welding skills (I had none) this weekend so hopefully I'll finish that tonight. I should have some pictures soon.
 
Sounds interesting.... just ensure that you aren't making it too 'solid' of a can that it blocks the wifi strength/connection. Good to hear you want to use the Espress module...are you going to connect it to a HM or are you building it with your own arduino=clone for the PID? Are you using a fan only or going with a servo/fan damper?

Keep us posted and pictures are always better!!!
 
DavidNP said:
Sounds interesting.... just ensure that you aren't making it too 'solid' of a can that it blocks the wifi strength/connection. Good to hear you want to use the Espress module...are you going to connect it to a HM or are you building it with your own arduino=clone for the PID? Are you using a fan only or going with a servo/fan damper?

Keep us posted and pictures are always better!!!
Click to expand...

Hi David! The "can" is actually a plastic one. I wanted to do a metal one, but I wanted to try to avoid condensation issues and not use an external antenna if possible. I'm using an HM, not my own AVR. It's not worth my time to do all that when a perfectly good PCB already exists. I'm going to go BLOWER-only for now and see how it works out. If I need a damper I'll come up with something at that time, but based on years of cooks I don't think I'll need it as long as I keep the wind out of the blower itself, methinks.

Photos soonly!
 
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Sounds cool, it is always fun to see new ideas and different assemblies! I've used an 8Ah 12V battery and it ran the pit for a full 24 hours before I turned it off so it is definitely workable, although the ambient temperature here was like 80F. Keep us posted with some pictures when you get it up and running.
 
Last night I was working on the mount for the blower and I didn't like how it was turning out. I want to get a nice seal around the outlet of the blower, but I think I will have to use some RTV for that. It's not the end of the world. I looked up other types of small DC fans and there are quite a few that draw a lot less current (which matters to my battery project). I don't know how some of these work at low speed/voltage, so that might be an issue, but why don't more people use a plain old square fan? http://www.mouser.com/ds/2/632/AFB40x40x10mm-A-515704.pdf this is the datasheet for just one of many I found. The squirrel cage blowers tend to have better performance at higher pressures, but if my air burner is free-flowing there should be little to no pressure there. A 10 cfm "box" fan will use 60ma at full tilt where as the squirrel cage 6.7 cfm fan used 250ma or so. If the box fan would work I could waaaaay downsize my battery.
 
AndyR said:
Last night I was working on the mount for the blower and I didn't like how it was turning out. I want to get a nice seal around the outlet of the blower, but I think I will have to use some RTV for that. It's not the end of the world. I looked up other types of small DC fans and there are quite a few that draw a lot less current (which matters to my battery project). I don't know how some of these work at low speed/voltage, so that might be an issue, but why don't more people use a plain old square fan? http://www.mouser.com/ds/2/632/AFB40x40x10mm-A-515704.pdf this is the datasheet for just one of many I found. The squirrel cage blowers tend to have better performance at higher pressures, but if my air burner is free-flowing there should be little to no pressure there. A 10 cfm "box" fan will use 60ma at full tilt where as the squirrel cage 6.7 cfm fan used 250ma or so. If the box fan would work I could waaaaay downsize my battery.
Click to expand...

Check out the MicroDamper thread. This utilizes a fan instead of a blower, with great results. There has been some people having issues using a fan with an "air burner" setup, as it creates a bit of pressure with the bends and holes and such. I'm sure SteveCK on the Microdamper thread could answer most of those questions.

There are blowers that use less current, and perform perfectly well. I use a Sunon 5.7CFM blower, and it only draws 120ma at max. I use this one in my adapt-a-damper, and have never had to run it over 30% max with my 18.5" WSM or my Char-griller Akorn.

Here's a link to the Sunon ... Sunon 5.7CFM Blower
 
WBegg said:
Check out the MicroDamper thread. This utilizes a fan instead of a blower, with great results. There has been some people having issues using a fan with an "air burner" setup, as it creates a bit of pressure with the bends and holes and such. I'm sure SteveCK on the Microdamper thread could answer most of those questions.

There are blowers that use less current, and perform perfectly well. I use a Sunon 5.7CFM blower, and it only draws 120ma at max. I use this one in my adapt-a-damper, and have never had to run it over 30% max with my 18.5" WSM or my Char-griller Akorn.

Here's a link to the Sunon ... Sunon 5.7CFM Blower
Click to expand...

I will check out the damper thread, I didn't know that used a fan. Thanks!
 
Some photos of the burner, etc:

EXP 12180 battery, sealed lead-acid, $33 from Amazon. Think of it as a small car battery. 18 amp-hours, 12v. If my math is correct this will last a few days worth of cooking, at least. The ammo can (plastic) is a Plano 1712. The plan is to mount the battery inside with all the electronics, run the wires out through a "flap" in the base, build/buy a battery charger and mount it inside, and create a spot to tuck the probes and blower into.
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This is the bulkhead with a 90 degree brass elbow and 1/2 NPT to 3/4 copper adapter installed. This is brass, 1/2 NPT threads on both ends and it goes into a 1.125" hole. Part number 50785K275 from www.mcmaster.com, $17. The gaskets are PTFE and rated to 600F, also from McMaster, p/n 5209K303, $7.19. You only need 1 of them, but I bought two just in case so I used them both. I also picked up a plain old flat washer and didn't use the lock washer.
files


Here are the probes I bought. I wasn't paying attention to the meat probe and ended up getting one with what looks like silicone insulation. Whatever, we'll see how long it takes to kill it.
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Here's the burner. It's 3/4 copper pipe with 45 degree elbows and whatnot. I tig'd it so the solder won't melt. Installed height is about 1" below the grate so we'll see how it goes there. I wanted to try to keep it above the ash pile. I can change it later if needed. I kept it a bit smaller in diameter, but I put a few angled holes to get air around the outside edges.
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This shows how I did the gear underneath. The bulkhead has the 90 degree elbow on it and I found a brass 1/2 NPT with a 7/8" OD (3/4 copper pipe is 7/8 OD) compression fitting on it that worked out perfectly. I annealed the 3/4 copper pipe with the propane torch and gave it a gentle bend to get it off the ground. There's around 1/4" gap between the bottom of the elbow and the ground. The aluminum shield had to go, but I don't know that it really did anything anyways.
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A couple of small issues.
You have a 1/2 to 3/4" adapter in there. That will be a flow restriction.
I'm not sure you have enough holes drilled or the ones you have drilled are big enough.
Given both of those "issues," I would stay with a blower over a fan.
The aluminum pan is a heat shield to help keep the cooker from starting a fire.
 
Andrew F said:
A couple of small issues.
You have a 1/2 to 3/4" adapter in there. That will be a flow restriction.
I'm not sure you have enough holes drilled or the ones you have drilled are big enough.
Given both of those "issues," I would stay with a blower over a fan.
The aluminum pan is a heat shield to help keep the cooker from starting a fire.
Click to expand...

I'm rolling with the blower that the parts list on Mouser had on it, 6.7CFM IIRC, for now. The holes I drilled add up to just a hair under 100% of the cross sectional area of the 1/2" pipe fittings, the smallest parts. I wanted to run under 100% to attempt to get somewhat of a jet effect at high speed. Based on what I've seen on the forum I shouldn't need to run anywhere near even 50% DC on the blower for a low-temp smoke, but eh? I can always add holes or make them bigger...
 
The HM is built without any drama, I just have to get a bootloader on it for the Arduino stuff. The Espress module is up and running and I'm surprised how good the wifi range is on it. I got all the thingspeak stuff going last night, too. I think I'd rather have a simple HTML page that shows all the data instead of running it through thingspeak. If there's enough memory left over in the AVR or esp8266 maybe I can store enough data points for a whole cook.

I looked into using MQTT, and I have a Linux server at home I can run it on, but sometimes I just want to keep it simple.

I rigged up the blower last night and did some airflow tests. The battery was at 13.4v and with the "burner" connected it was working a little harder at full power. At about 75% and under there was little resistance to my ear. Yes, scientific. I'll grab some pix of the blower "module" today. It's basically a large diameter PVC tee with the fan glued into place inside. One end of the tee is capped and the other end points toward the ground. This should give a measure of wind resistance, but that's one of the experiments I want to run, hopefully tonight.
 
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FYI....don't know which version of EspressModule you downloaded but yesterday I uploaded Jason's changes to github with v1.2 (that version has a simple page for local/direct access to the HM, no graphing yet).

Why no 'love' for thingspeak? Easy to setup and use, works outside home with no internet port-forwarding (security issues)...keeps history of graphs for all your cooks....twitter alerts.....I just make the 'thingpseak-html-link' on my mobile phone home screen and its good to go (like an app). Is it the dashboard layout you don't like?

I wouldn't use MQTT unless you're already using something like openhab/or other home automation already....
 
DavidNP said:
FYI....don't know which version of EspressModule you downloaded but yesterday I uploaded Jason's changes to github with v1.2 (that version has a simple page for local/direct access to the HM, no graphing yet).

Why no 'love' for thingspeak? Easy to setup and use, works outside home with no internet port-forwarding (security issues)...keeps history of graphs for all your cooks....twitter alerts.....I just make the 'thingpseak-html-link' on my mobile phone home screen and its good to go (like an app). Is it the dashboard layout you don't like?

I wouldn't use MQTT unless you're already using something like openhab/or other home automation already....
Click to expand...

I saw you were in there updating things so I grabbed the latest version of 1.2 last night. I was just looking all over the place and I can't figure out what actual version number it is because I just grabbed the BIN and flashed it. Maybe you want to put a version number in the HTML? Not a big deal really.

I have some love for thingspeak, it seems to work well and skipping the whole firewall/security stuff is good for the newbs, too. The JS dashboard looks great, put it on the espress :) I just want to connect directly to the unit and skip all that config and those points of failure. If I don't have an internet connection I want to be able to have full functionality in AP mode. To access it remotely (when I do have an internet connection) I can run it on some weird port or bounce it off of my own . It would be nice to set up a mobile app, too. I might give that a shot one of these days.

My goal is to run this smoker on battery power and without an internet connection, without buttons or LCD, but using a mobile device for setup. I didn't even assemble the LCD/button board on the HM.

Oh, and I hate Twitter. And teh Facespace. I'd rather have an email or text alert on my phone, or an alert via the app that I need to write (in the distant future).

Please don't take any of this as a slight because you've done awesome work and I will enjoy it for a long time! I'm more than willing to contribute to the code and testing. Right now the thing is sitting in a box with the battery out in the snow in the yard.
 
Also - I meant to ask you - can I use any BIN file or do I need to use the one you supply for flashing the AVR?
 
if you're on 1.2, make sure you copy over the new html files as they have the feature of off-line and direct access to HM...good idea, I'll add a version to somewhere via html...

BIN files are for esp8266 firmwares(those are made by the IDE compile)....AVR files are for the atmega flashing....you can make your own AVR files if you compile your own HM from source. You just need a small batch file that will convert the hex file from the ide to AVR file for AVR flashing. Let me know and I can pm you the batch file....
 
I'll take the batch file, please! I ended up flashing the bootloader and compiled the source from Arduino and uploaded it. The esp changes and reads the settings correctly on the HM, so it's alive, but it's not reading my probes for some reason. I need to go over the docs again because I just plugged and prayed.

I used a completely new copy of the whole git before I started it, so I should be good on the htm file.
 
Something is messed up here, I don't know what I did. The localhm.html page only shows:

pit probe at 11 degrees
fan 0%
setpoint 21 deg

I wonder if there is some initial setup that gets done in the HM AVR when you have the lcd/buttons installed that I'm missing out on here.
 
Bryan and others - I'm having a problem, I believe, with the HM software? I flashed my new 328P chip, bootloader and HM code and it seemed to work fine, without error. But I couldn't get anything to happen, it appeared dead. So I found an Arduino Uno R3 today, brand new. I downloaded the entire git and opened up the code in the Arduino IDE. I added the 4 libraries and it compiled and uploaded without errors. I tried various things beyond this point to get something to happen on the serial interface (38.4k), but nothing appears. This is with the AVR still plugged into the Uno board and using the Arduio IDE's serial monitor, which I believe should work with this.

Is there something else I need to do to get it running? Keep in mind I have no LCD or button board plugged in, I didn't even solder up the connectors for them on the base board.
 
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