Wideband A/F Meters - Again, Maybe build our own?? Options

[KenH]

Anybody using this unit - less than $300

http://www.ngksparkplugs.com/products/air-...9000&country=US

http://www.ngksparkplugs.com/pdf/AFX_Tunin...anual_Rev04.pdf

http://www.ngk.com/results_cross.asp?pid=91101&s=10

Is anyboby interested in building any units?? Does anyboby have a design?? I can do hardware but need sombody that can write "code".

Ken

[lapuwali]

QUOTE (KenH @ Dec 27 2005, 09:35 AM)

QUOTE (lapuwali @ Dec 24 2005, 04:18 PM) A display for either the LC-1 or the 2A0 is pretty easy to design and make, much easier than a complete WB02 board would be.  If you're using aftermarket EFI that can take in a linear AFR signal (I know both MS and SDS will do this), the LC-1 is the killer deal, as it even has two outputs, one for the ECU, one for the gauge, and both are programmable in terms of output range for AFR. Do you have a design for the display?? Ken

There are a zillion of them on the Net, but here's an example:

NB gauge design

They're all based around the National LM3914 voltage to bar-graph chip, basically making a voltmeter with a bar graph display, which you can tune in terms of range with a couple of resistors. The LC-1 can be programmed to display the AFR as any voltage range, so setting it up to use the narrowband voltage range (0-1v, 0.5v = 14.7) is easy (may even come that way as the default). So, any of the many designs you'll find on the web for displays for a narrowband sensor will work.

The example I showed uses one LM3914 to drive 10 LEDs, but you can chain these chips together to get 20 LEDs if you want more resolution.

Since the LC-1 analog outputs are programmable, you can also use a digital panel voltmeter and program the outputs so 14.7:1 shows up as 1.47v, 10:1 shows up as 1.00v, and 20:1 shows up as 2.00v. The LC-1 is probably limited to 5.0v max, so you'd have to mentally move the decimal point. You can pick up a panel meter very cheaply from several places, like Jameco:

Jameco Panel Meter