Wood Gas Mixture Controller

Arduino Uno based wood gas mixture controller.

The controller consists of a custom circuit board allowing the unit to operate on 12-24V, an Arduino Uno, narrow band oxygen sensor, and servo valve assembly.

Please note this O2 sensor does not have a heater and requires approximately two minutes in a running exhaust stream to come up to functional temperatures.

Price: $385 plus shipping.


11 thoughts on “Wood Gas Mixture Controller”

  1. Hi there,


    Funny enough, I have just completed something very similar: Arduino + servo + wideband sensor + custom-built throttle. However, my custom built butterfly valve doesn’t close hermetically shut like a ball valve. For gasoline – it works very well, but for woodgas, sometimes it lacks tightness for pulling enough vacuum out of the gasifier.

    At first, I thought I’ll use a ball valve too, but they it was very stiff and servo couldn’t turn it. Would you share how did you make your ball valve easy to turn?

    Best wishes,

    • Hi Linas..Just put a pipe nipple in each end and unscrew the valve body one turn. The nipples are so the body doesn’t distort. They are very tight. Also unscrew the handle nut one turn.

  2. ever considered a mechanical governor like the engines carb would have had originaly

    • Steve. The old mechanical governors allowed the engine to run at a constant speed despite a fluctuating load by modulating the throttle. This device controls the chemical composition of the exhaust which is an entirely different concept. The generators I run still have their mechanical governors in place and working for load control.

  3. Alen Lipovac said:

    Hello from Croatia.
    Sir, I am waiting for my arduino and servo motor. Here in Croatia we have Croatian version of arduino called Croduino. I think it is cheaper and maybe better.
    Anyway, I do not have the skills to write code for mixer so I would like to ask you if there is any chance to share code.

    • Hi Alen…Unfortunately this is how I make my living so I am not inclined to release code. I would be happy to sell you a mixer when I am done with the testing and validation. Stephen

  4. Hi Stephen
    Your automatic air gas mixer is it to the point now?
    what is its price?
    what type of probe do you use?

    • Hi Thierry….Not yet. The problem has not been with the electronics but rather my generator. My green generator doesn’t like wood gas at all. I think it is a low compression problem. After spending a month trying to get that to run I finally broke down and bought a new generator which is on the “Generators” page. Now I can start the testing I should have been doing last month. Sorry. There will be posts coming as soon as I get things running.

  5. is that black valve inbetween the t and the blue hose ? is it a a flame arrestor or check valve ??

  6. thanks for your quick reply

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