E30 Zone

I completed this project a little bit ago, and thought I would share it with you. I'm an e30 fanatic from the U.S. and in my spare time I like to make things. I have a '89 325is with a m30b35 under the hood. Build thread here: (http://www.e30zone.net/modules.php?name ... highlight=)

I'll post to it as I go along. (Eat a dick Mach - you cheeky bastard)

So, please post or subscribe to the thread and follow along with me!

**To my friends that have already seen were this thread maybe heading - I ask that you don't ruin the surprise!**

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So, many of you have seen my interior light delay with auto dimming that I make: http://www.e30zone.net/modules.php?name ... highlight=

Hopefully this will spark some creativity from you all to go and explore on your own.

So just what the hell is this? Well, my car is not turbo'ed. No Mega-squirt. I have no real need for super huge gauges all over my dash. I like the stock *look*. But I wanted to add an extra gauge here or there, and yet have the interior look totally stock. So ”“ I'll be needing to "sneak" these in the dash some where. Where is the question. I don't want "pods" of things looking like rice cakes poking out of the a-pillers.

I thought about sneaking it into the instrument cluster - but that requires a ton of work.

How about INSIDE a hollowed out hazard or defrost switch? That would look pretty stock? Not to mention no cutting or drilling - just pop out one of the "blanks" and slide that puppy in. Yea that will do - can it fit? I bet it can.

I happened to have a few extra switches lying around. Time to crack one open.



They take some persuading to get them open. Two small screwdrivers does the trick.



The 20 year old innards spill right out. All I care about is the front of the "bezel/case" and the front "button" - The button is a bit thick and dark, but I have a plan for that.



So - about the only "display" you can squeeze into a hazard switch is a LED bar graph. Perfect for a simple gauge - I don't need a numeric display - just something much smarter than a dummy light - and something less than a laptop riding co-polit.

A quick look at my boxes of parts lead me to the venerable LM3914. It's a linear LED driver. Basically you tell it the limits of the signal it will receive, and then you feed it a signal, and it can drive 10 leds to make a guage.



It's made by National Semiconductor - and it's pretty fool proof. In testing it - I threw 20 volts on it's input pin, and everything else to see if I could fry it - no go - it's a trooper. It's not too happy if you hook it up backwards to power - but that's fixable with a diode.

Next step - pull out the parts - I have dozens of boxes like this.



Fast forward to some internet searches on the LM3914 and I'm 90% there - throw in a diode to protect the circuit, and some capacitors to filter the nasty input voltage of a car, and a few more for good measure...I won't bother you with the details...



After a few hours, I have a good hand drawn diagram - time to fire up the rig...And I have it in the computer - this will help me in the VERY complex part of the project - making the circuit board.



Now if this was 1992, I'd have to face one of these bad boys...



I know the parts I need are in there somewhere!!!!



Oh god - this could take for ever...Luckly - it's all on line...



After some more research - I know EXACTLY what I want. I'll mock up the circuit - and cross my fingers...



And it works!!! Ok - I made it look easy, it's a lot of work.



Next up - is taking it from prototype to the real world.[/url]

Got a bit more done.

Once you have a working circuit and have tested it - it's time to start designing the PCB. Now, you remember the match stick games you would play as a kid? This is kinda like that but on crack. Your goal is to organize all the traces on the PCB so that the all parts connect to one another with out a single line over lapping - it's sick fun.

Here is the start - see all the "crossed" lines - that's no good.



Just when you move one component to fix something, it screws something else up. You do that till you are blue in the face.

After a few hours and lots of hair pulling, here is what it looks like. If it looks like I got "lucky" and everything just happen to fall into place - then I did my job.



A paper mock up - got it to just the right size to fit the "case" - no easy task



Kinda small hun? What ya think?

It still has room for improvement. So I'll do a mock up and see how everything fits. I can still tighten up alot of parts if need be.

Next up - build a one-off prototype.

Very interesting indeed, wonder what it could be for?

Well it can display about any value you can think of.

I call these "smart idiot lights" - cause they do one thing, and do it well. They let you keep track of a important value, while keeping your interior looking classy. Not ment for tuning - but very handy to keep an eye on things.

It turns out the 3 things most useful in a gauge like this is voltage, wideband AFR and narrowband AFR.

I would have guessed at air/fuel ratio gauge due to the LED's, very similar to something else ive seen

How much NOZ is left in the tank?

Can they do oil pressure/oil temperature?
Perhaps even switch between the two?

m_jermyn wrote:How much NOZ is left in the tank?

nozzzzzzzzzzz!

daimlerman wrote:Can they do oil pressure/oil temperature?
Perhaps even switch between the two?

Good questions. Those sensors are not linear in their output, so you could measure oil pressure and temp with this gauge, but it would require some addition parts. I'm working on some other things that will led themselves to oil temp/pressure.

WOOOSH....time for an update. BTW - keep in mind - this is just a mock up.

So, time to make some circuit boards...



Since the LED bar graph has to be at a right angle to the main board, I'll need to make a tiny tiny board (did I say tiny?) - I'm getting good at making micro sided parts.


Here is the two together - the main board is all done. I'm not 100% happy with the placement of the components - but that is what a one-off is for. I'll tweak it a bit more. Plus, I'll be using much smaller capacitors, that will make a big difference. I just used what I had on hand. All parts will be custom ordered.


This picture is deceiving...this is SMALL...Don't believe me? Go grab a quarter. I'll wait... ;)


Next up is to try to see if it will fit into the case.

Very very clever, I wish I could so stuff like that

Yep, it fits


Just chillin' in it's new home - it will need to be centered of course!!!


Cute little threesome, no?


The LED display is resting in the "button" - not it's final position.


Next up: Modifying the button, and installing it into the case.

Didn't get as much done as I wanted to...

Time to start dealing with the thick and dark button. The factory uses a little 5 watt bulb to light up the button - that is actually a lot of light. I'll need to make the button a little more LED friendly. With that and picking the right LED's, Ill have a good match.

Stock thickness is 0.04" - Pull out the calculator, and I'm shooting for about 0.015" thick - BTW that micrometer is older than you or your BMW...


Time to bust out the sand paper - I'm going to thin this thing down - very carefully.


Sand, sand, sand...

Good news? - I'm getting a ton more light in, exactly what I wanted.

Bad news? I've got a button all scratched up. No problem, I can fix that.


Kick it up to 1500....

Getting there...this is taking longer to do that I care for...

The factory button has a "textured" surface to it. I could stop at this point and replicate that surface by hitting it with some polyurethane, or automotive clear coat. Using a technique I'll call "spraying it up dry" - basically hold the can too far away from the part so that the paint dries a bit in the air. The result is a "dry" textured look, not wet.

But I kinda wanted to *bling* it out a tiny bit...

I'm sure this pic needs a caption of it's own...

Yea, that looks like the biz...

Don't judge the brightness by this pic. It's not the actual LED's I'll end up using - it's only what I had on hand. It will be bright enough for daytime and dark enough for night time - Very close to your SI light in the cluster in brightness.

Time to epoxy. I could have used silicone, but thinning out the button this much, you could accidentally damage it if you were in a panic and pushed on it thinking it was the hazard. This stiffens it all back up.

Yep - that is what I call stealthy!!!


Next up:

- figure out how to solidly mount it in the case (I think I have a plan)
- install it in the car
- Modify the circuit for the following:
Voltage
Boost
Wideband Air Fuel
Narrowband Air Fuel

Hi George

You have a PM

OMG get these ready for sale! these ae mint and would sell well!!

are you knightrider ?

Want

jimmyspeed wrote:are you knightrider ?

No. I'm the 'hoff.



I got some switches in for more testing and mockups



Here is what $200 in electronic components looks like. Kinda sad hun? You'd think you get more for your money. Most bags have only 4-5 parts in them.




Here is one finished board. (ohh clean fingernails FTW) The design is all finished and ready for production. This one measures voltage. It will show you the condition of the battery, and if your alternator is charging.

Excellent stuff George

V Cool dude!

Very cool where do I send money for one

You need to concentrate on ones for lambda readouts/AFR, I would buy one

DanThe wrote:You need to concentrate on ones for lambda readouts/AFR, I would buy one

Wideband or Narrowband?

And the finished product minus the button/case.

Looks pretty.

How do we get one to work? What else do you need to make this thing go?

Mike

Nothing - they are self contained just like any other gauge.

More update soon - and some better photos of the finished project.

amazing work!!!!