Using a Mass Air Flow Sensor in a Furnace

OK, you guys probably thinkI am slacking since I have not posted to this thread for a couple days. I have had limited time for this project as I have been very busy molding sand, cleaning and shipping castings, refining a patterns, and making aluminum flask parts.

But, last night I did hook up the sensor to 12v and tried to find a signal either as a wave-form using my oscilloscope (I sure wish I had an oscilloscope mentor here as I am pretty green with respect to scopes) and using a VOM looking for a DC voltage signal. So far, no joy.

The scope.


To get air flow through the sensor , I used a home vac taped to the sensor. Seemed like a good idea.




Of course, I do not know for SURE that I have the right leads hooked up for power, Gnd, and signal :-(

Wading into something like this with no clear guidelines adds to the fun.

So, sometime today I hope to try to check out the MAF’s on my truck and Subaru to see if I can find a signal.

Denis

 

I presume that you are using a digital VOM and not an analog one?

 

Yes, digital. My much-loved 1970-vintage Radio Shack analogue meter died a couple years ago.

Denis

 

I had a look around online for info about your airflow sensor and couldn't find anything definitive apart from the principle of function. I did find an Arduino board for a sensor running off the "hot wire" principle for $24 complete with sample software. It outputs a 0-3.3V voltage proportional to airflow and is capable of measuring 150 MPH wind speeds. It's not nearly as rugged as your unit but at least the circuit and function is well documented and that's worth paying for.

https://moderndevice.com/product/wind-sensor-rev-p/

Edit: looks like there are none in stock at present.

 

A search of Mass Air Flow + arduino or MAF+ MegaSquirt might reveal some previous work.
I did find this, https://wiki.dfrobot.com/F1031V_Mass_Air_Flow_Sensor_SKU_SEN0360
Although it probably isn't directly your MAF, it might spark some ideas.

Also on an ECU (Speeduino) that I'm playing with, I found this:
https://speeduino.com/forum/viewtop...9631&hilit=Mass+air+flow+sensor+output#p49631
There is a visual of the signal he's getting from his. I know some are a 0-5v out, and some are PWM.

 

Boroko, thanks for that info. It is helpful. This sensor project has had to go to the back burner as I’ve been slammed with casting orders and machining. I’ll be looking for a signal pattern like that shown. I will get back to this “when I catch up.”

Denis

 

A thought that came to me is to pick up a cheap anemometer and just use it as a relative measure to calculate your air. https://www.amazon.com/Digital-Anem...sspa?_encoding=UTF8&c=ts&keywords=Anemometers

 

I don't want to sound too stupid but don't all current MAF sensor or any other sensor in the car today use a can protocol? I did try this with sensors from odb 1 years and I could get an frequency output that appeared to be linear, although it's hard to truly tell because I was using a centrifugal style fan which does not have a liner output. I think the old sensors are better suited for this type of thing. One could use one of the modern development boards like a arduino to communicate with the newer sensors but that in itself sounds like a project.
I guess this thread is a bit old, I didn't notice been quite a while since I've been here.

 

Yes, theMAF is on the back burnerright now. Before turning my attention to other things I did try to determine the output of the unit I have. No luck, so far. If anyone has some info on this, I'd appreciate it.

Denis