My Barbduino Project

Earlier, I posted about my plans to build a digital controller for my Traeger pellet grill using the Arduino open source microcontroller board.

I’m new to the Arduino (although not to programming), so my first step was to buy a simple Arduino experimenter’s kit and do some general non-BBQ projects, to familiarise myself with the kit and its capabilities. This is still ongoing. I made a point only to buy the Arduino kit, and not the add-ons I might later require, such as the WiFi and LCD Screen options – doing so means I will learn to walk before I run, and limits my spend, in case the project doesn’t fly.

However, in my head I already had a grand plan for what it would do – controlling all aspects of the grill, connecting to my home network by WiFi, running a simple web-server displaying the temperatures. It is easy to let your imagination get carried away.

I have now thrown away those ideas, and replaced them with a simpler plan that will be a lot easier to achieve, while still allowing me to develop it further at a later date.

The manual controller currently controls three things: the igniter rod, which heats up for the first 4 minutes the grill is switched on, and ignites the pellets; the auger, which feeds the grill with pellets for fuel; and the fan, which is wired into the main controller on/off switch and provides air for combustion.

For the moment, the existing manual controller is going to remain in place, with the Arduino connected in parallel in the auger motor circuit. The manual controller will continue to control the igniter rod.

The connection from the manual controller to the auger motor is going to be interupted by a relay connected to the Arduino, which will be normally closed. This means that when the Arduino is unpowered, the manual controller is controlling the auger motor. When the Arduino is in use (and controlling the auger motor via a second relay), the manual controller is taken out of the auger circuit.

The WiFi element is now removed, and replaced by my netbook, connected to the Arduino by USB, and receiving a simple feed of temperature data. The netbook is also what will power the Arduino.

The advantage of all of this is that my regular cooking need not be hindered by my experiments; and even when the project is finished, in the event of any problem – hardware or software – I can revert to the manual controller simply by unplugging my netbook, and removing power from the Arduino.

The removal of the need for WiFi or onboard LCD display makes things a lot simpler, and means I can concentrate on the actual control loop. It also means I can develop my ideas for no additional cost that the kit I have already purchased, plus a couple of relays.

For remote control, I can run VNC on my netbook, and connect from my desktop or phone, and monitor temperatures.

I’ve seldom used my netbook since getting my Android phone, so it will be good to find a use for it.

As you can see, my project has also received a name – the Barbduino. Cheesy, perhaps, but I like it.

2 Comments

  1. June 5, 2011

    Ah, you’re wiser (or at least more disciplined) than I am. My projects always suffer from “feeping creaturitis”, to the point where they become impossible or at least unfeasible and then get dropped.

    • chris
      June 5, 2011

      But the temptation to add features is always there.

      I’ve read of other people with the same or similar grill to mine leave it for a long cook, only to come back and realise that it stopped an hour ago, due to lack of pellets.

      I’ve always thought “how could they let that happen?”, until yesterday, it happened to me – doing 5 things at once, and I forgot to fill the pellet hopper. Not a catastophe, as I spotted the temperature going down.

      Anyway, it quickly occurred to me that by drilling two holes in the pellet hopper, one low down, with a bright LED, and one high up with a light sensor, I could easily add a “Pellet low alarm” – when the LED is covered by pellets, the light sensor wouldn’t detect the light, but when pellets run low, it would.

      It seems a simple thing to add (and I already have the components), but what is simpler still is to make sure I remember to fill the hopper in future!

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