DIY Air Fuel Ratio Meter Gauge

Yesterday, I just browsing through internet to find some information regarding AFR meter. Than i stumble upon a video on youtube on DIY AFR. just require some small amount of money, soldering skills and some free time to complete the job. Than i think its maybe suited me.

Than I gather some more information on the net on how to make this things. I am on this two website.

The 1st one is D.I.Y. air/fuel ratio meter on Redline

It got all the information i need to DIY this thing. However, bacause it's lack of information. i decide to dump the idea. from the website.

Than I am into this website DIY Air / Fuel Ratio Metering by Wing Gee. It's got a lot of information and i decided to go with the idea from the website. here's the circuit for the gauge.



Than I went to a electronics shop and buy all the components related to the gauge. i got all of it just for RM13. Pretty cheap if compare with a proper AFR gauge that require at least RM80

Than using my skills, i assemble all the components altogether. Here's the details on led color stands for.

0.0V-0.2V stands for lean mixture as red led
0.3V-0.8V stands for stoich mixture as green led
0.8V-1.0V stands for rich mixture as yellow led

LM3914 and 5V voltage regulator circuit board
(Front)


LM3914 and 5V voltage regulator circuit board
(Back)


10 LED connected


Full size meter gauge


Installed in the car


Here's the meter on action

My boost meter (Autogauge electronic boost meter)

I just install a boost meter into my car. its a really cheap stuff. Brought a used unit for 50 ringgit only. I can tell, its best for the bang buck. the meter is Autogauge 60MM electronic boost meter. Here's the link to the product catalog details. Bought it from a nice chap from zero to hundred market place.



Installation for the meter is straight forward. The meter got four wire to connect. I cant remember correctly the wire colour code. What I am sure is the black wire is connected to ground. Another two of them connected to +12V and anoter one connected to headlamp switch. Work like charm after finish wiring it.

Wire connected to boost sensor is pretty short. It's a three core wire. Red is 12V, black is ground and white is for signal. I need to make sure the wire longer because i need to mount the meter in the engine bay. so i just cut and rewire it back with some kind of telephone wire i think. It's got three single core copper line. I bought it at hardware shop pretty cheap. its RM5 for 5meters.

Nice feeling when it's working perfectly after some DIY.