Home-grown Traeger Control Idea

[Chris__M]

As mentioned in the "How do i use a Traeger?" topic on "Help & Advice", I recently posted an idea on PelletHeads. Although the responses I got were both helpful and interesting, they mainly seemed to address other ways that I could achieve what I was talking about (either buy a digital controller, or a Stoker with a DPDT relay), rather than my suggestion itself. Or maybe that is sour grapes on my part, 'cos no-one said "That's Brilliant"!

The whole idea is to allow me to play about with the Traeger, *without* spending lots of money, or permanently changing my Lil' Tex. Now that winter is over, I'm actually getting on fine with the 3 way controller, but I like tinkering; and it may be even colder next year!

The idea revives around an X10 home automation module that I have already sitting in my spares box. This means the initial part of my idea will be zero cost. The X10 module is a 240V on-off switch (not a dimmer), which can be controlled by signals sent over the mains, either from a control switch or (more interesting) from a computer.

Using the appropriate Molex connectors, I thought of installing by-pass wiring so I can either use the 3 way switch, or have it controlled as follows:

1) Hot rod still controlled by 3-way controller.

2) Fan always on (i.e. controlled by 3-way controller).

3) Auger controlled by the X10 module.

This will allow me to use my computer to control the timings of the auger, and with a simple script, have any combination of on/off timings that I like.

For instance, I think the standard 3-way switch uses the following settings, on a 4 minute cycle.

Smoke: 1 min on, 3 mins off
Med: 2 mins on, 2 mins off
High: Always on

Controlling the auger from a script will give me the ability to have settings between these. For instance, if it is cold out, and Smoke is not getting up to temperature, I could have 1.25 mins on, 2.75 mins off. (I would also probably use a shorter cycle, replacing 1 min on/3 mins off with 15 secs on/45 secs off.)

It still won't be temperature control, but it would give me much finer control. If I see the temperature is climbing on my MT73, I just tweak the on/off interval. More to the point, most of my smoking is done while I work from my office upstairs (in front of a computer). So changing a setting on my desktop, that sends a signal downstairs is much more convenient than running downstairs when I see the temperature is not right.

All of the above I can do for the cost of a couple of Molex connectors.

The possible (but not obligatory) second stage of the plan would be to find a way of getting the grill temperature into my computer. This may mean buying a Stoker. I would then need to see what info the Stoker gives me, and how I can adapt it to control my script. However (and this is the important bit) the Stoker will not be turning the Traeger auger (or fan) on and off. It will be telling my script what the grill temperature is, allowing the script to determine which cycle is appropriate to use. So rather than it being an on/off scenario, it will be a question of changing from 15 secs on/45 secs off to 20 secs on/40 secs off.

Hopefully this would avoid the violent temperature swings I have read about when trying to automate temperature control on a Traeger.

What do people think, am I insane? For the moment, I would appreciate comments on my specific idea (even if it is "it won't work, because...") rather than alternate ways of doing this. One of the benefits of my suggested method is that I can experiment with whether my basic timing method works before spending any money on a Stoker, or alternative. If the script doesn't work while I am controlling it manually, I can simply write the idea off.

Note that I programme in perl for a living, so the complexity of the script will not be an issue.

[Steve]

The idea is sound for finer control. I imagine the perl script would be a doddle to knock up as well. If you've already got the X10 switch and the control unit for your computer then it's going to be an improvement for you.

When it comes to temperature monitoring and control the cheapest option is likely to be a digital controller, the coolest easy option the stoker or the most fun option, a couple of triacs, a PIC, a thermocouple + controller IC and some strip board.

I've already looked into control for pellet poopers and it's pretty easy to do. I've just had zero time to actually do something about it. It'll cost more than a digital controller but would be way cooler as it could be wired up to ethernet if you choose the right microprocessor.

[Chris__M]

I've just taken delivery of an Arduino basic kit, to experiment with. For the moment, I am going to be playing with flashing LEDs, but once I know what I am doing, it is relatively easy to add relays, LCD screen and even WiFi.

[Chris__M]

Not sure at the moment, as I haven't delved far enough. I already have an ET-73, and I've read (but haven't verified myself) that the probes from this can be used with the Arduino. If that works, it will certainly be fine for my experiments.

I've found a number of references to people doing smoker control with the Arduino, but all that I have found so far involve fan control of charcoal grills, in a similar fashion to the Stoker. Obviously the temperature monitering side will be the same, so I can crib from them, but many folk have already discovered that controlling fuel and controlling airflow have different requirements, not least the need to cut the pellet feed *before* the target grill temperature is reached. Sp the control side of things is probably going to be written from scratch.

It's going to be an adventure, and will need some experimentation. I don't know how long it will take me - partly cos my day job is a mixture of consulting and writing code; and when I am coding during the day, the last thing I want to do is do it in the evenings! However, it looks like I have a couple of months consulting work ahead of me, so that bodes well for home projects.

A few of my visitors today are almost as geeky as me, and after admiring the grill, and working out from observation how it worked (they wouldn't let me tell them, and I wouldn't let them take it apart), we got out the Arduino to pass round and go "oooh!". It is a dinky little thing, much smaller than I'd imagined.

[Chris__M]

Here's a web page from one of the arduino grill control guys - as I say, his design is controlling a blower.

http://hruska.us/tempmon/

[Chris__M]

It is too complicated.
Look my other topic.
A digital thermostat, a blower, a voltage regulator, a 4 A.H gel battery. Set smoking temperature, this combination will keep it 24 hours. total cost US$60.
or a PID thermostat, a battery, a blower. total cost US$120. Programmable in 24 hours. Say 6 hours of 105C, then 3 hours at 110C, following 1 hours of 120C, finally half hour of 130C. Or what ever you program.

Rather than look at your other topic, if you read *this* topic, you will see any solution using a blower is irrelevent to me. I am using a pellet grill, which requires a 240V AC auger motor to be controlled. This is a different problem to controlling a blower, and if you use the same method, you will end up with wild temperature swings, and (some have reported) soot in your grill.

Also, running off a battery is no help to me, as my grill itself requires 240V AC.

As for being complicated, did I mention that I programme for a living?

As I have already commented, there are others who are now successfully using a PID to control a pellet auger, they are now getting good results, but it has taken them a lot of experimentation getting the settings right. At the time I decided to go with the Arduino, they hadn't yet got it completely right. Note that as we are controlling 240V AC components, even the PID will require additional relay circuits.

What neither of your solutions give me is remote monitoring, remote *control*, and temperature logging. Nor will they give me the satisfaction I will get when the whole thing is (eventually) working. It's about the journey, not just the destination.

As for cost, an standard Arduino comes in at 30-35 quid - I have seen clones as cheap as 15 quid. Admitedly, the WiFi shield I am planning to add is another 50 quid (the most expensive component), but I am not buying that until I have established results with the basic kit.

So thanks very much, but I'll keep going with developing my solution.