I'm in the process of designing & building a little circuit board that does a variety of nifty things - A/F ratio readout, primary & secondary injector duty cycles, and several RPM switches (one or two for 6th port actuation (possibly selectable actuation RPMs), and another one for... something, if I need it. VDI for the S5s, maybe).

If I can find the needed connectors, I'm planning to build it as a plug-in board - the needed connections are pulled out of an adapter that sits between the harness & the ECU - no cutting or splicing needed. The output would be a LED display, either using bar graphs, or rows of LEDs.

I'm looking into playing with the CPU inputs/outputs as well, to add features like a brake light tap switch (for when you're engine braking through the gears and people almost hit you because you never light up your brakes), and a tail light cutoff switch (zero rear/side illumination - you figure out the uses). It would be the same deal - plug in adapter & go.

Would anyone else be interested in something like this? If it works out, I'm planning to get printed circuit boards made (I've designed them before, so it's not a big deal). I'd probably sell them as a complete soldered unit, as well as a kit with all the parts, and you solder them yourself (and then have to find a way to calibrate the injector monitor yourself). I haven't priced things out fully yet, but it would easily be under $100 for everything.

And before anyone tells me, yes, I'm aware that threads like this usually result in a lot of "Yea, that's cool, I'll buy one" followed by "Eh, I really don't have the money right now..." when it's up for sale. I plan to take a deposit before getting the PCBs made (at least for the first batch) to make sure I'm not stuck with a boatload of things nobody wants.

-=Russ=-

 

EDIT: dp

 

If you build it, they will come.

 

Heh... I can forsee the future: You're going to get butt-r...err sued. You're opening yourself to such a HUGE liability with even thouching the brake system for any reason. I would leave that idea completely out or you'll be paying for every accident that even remotely involved a car that had this doodad installed on it...

 

if u manage to make something that displays % throttle, inj duty cycle i'd be interested......i figure most people would want ready made aftermarket WBO2 anyway...ohh yeah...make sure the LED panel is BIG.....with BRIGHT RED NUMBERS!!.....i would hate having to squent to read the numbers

 

Hm... I can't read % throttle on a S4 very easily. I suppose on an S5 it could be tied into the full range TPS. Sadly, I don't have a S5 to play with.

Good point on the light modifications... I might just leave that out. I tend to think of the technical aspects, not the legal ones.

I was planning to go with just 10 LEDs, bar-graph style... would a 7-segment display driver be really worth messing with?

-=Russ=-

 

it'd be a huge headach to mess with...but if u have the time..why not...as far as i know....its how u set up the resistors

 

what kind of size are we talking about for this thing? stereo DIN? thatd be kinda cool...

 

Well, I'm probably going to make it something fairly small. At least for the display unit. The main circuit board will probably be a decent size - I'm guessing at least 3"x3". It will be mountable out of the way, though.

The other thing is, building your own display unit would be fairly easy. Suggestions are welcome though. Personally I think a LED bar graph is easier to read than a digital readout of injector duty cycle, but I'll see if I can work something out for the latter.

-=Russ=-

 

theres no way you could post pics is there? I guess not if u haven't built any...

maybe you have like one you could show us?

 

It would be a lot better to get a numerical readout for the duty cycle then a bar graph, IMHO.

It's a really neat idea, I'd be interested in seeing a prototype.

If I did buy one, I don't want any brake light stuff on it.

 

Haven't built it yet, ordering parts for it this next week or so, building it when I have time between classwork. Hopefully by the end of thanksgiving break I'll have something working.

The problem with a digital readout, nice as it would be, is that it increases the complexity (and cost) significantly. I can do a bar graph with some analog magic, but a digital readout requires some significantly greater magic (unless I do something sloppy like just read it in 5% increments or something).

I'll look into it and see what I can do.

-=Russ=-