I want to put a few gauges in, so I know when I'm about to blow things up. Without much thinking I start going through an Autometer collection and find a bunch of cheap stuff that basically works.

I want something better though. I'm a geek, and I react quickly to blinkenlights, I want warning lights. Regular gauges always point at soemthing, and I'm definitely not going to try to decypher the precise values of the oil pressure dropping while pulling 1G in a corner.

So I start looking some more, going back into the dark side of import gizmos (I do love my supra) and starting to look at electronic gauges, with peak hold, 30 sec playback, and other neat trickery. Nice, but expensive. I look at the newer Autometer electronic gauges, and they seem to do the same things, but at pretty much the same prices. While browsing import gauges though, I came across Defi's site. I knew about Defi, but they were always on the high end, pricey end of the spectrum.

These guys have, what seems like a controller, with a serial bus connecting to all other components of the system.

please take a look at these links:
http://www.defi-shop.com/product/dp/dp_top.html

Main controller sets all the warnings, units, etc, for all gauges plugged into it. Then I found a
Defi Link Display. It's basically a digital readout of precise values that normally get 'visuallized' by the gauges. I look at the schematic of the system and I get an idea: what about forgetting the gauges, and just going with sensors feeding the info to the control box, and the display box providing me with readout/warning blinkenlights?

http://www.defi-shop.com/product/dl/capa.html

One of the examples on this page pictures exactly this: gaugeless gauges. You see the values on a digital readout, not traditional gauge with a needle pointer.

This is it! I think to myself, all the functionality, way less space. Price comes out about the same after getting the two boxes and the 4 sensor sets for what I want (about $820 total)

http://www.defi-shop.com/product/dp/dp_parts.html

Looks good, doesn't it?

This is the problem though: Why do I need to pay 820bux for 4 lights to blink at me? Shouldn't this be achievable with 4 LED's? Afterall, the D in LED does stand for diode, and if recall correctly (been a while, feel free to correct me) that means the LED should light up if the voltage goes over or under a certain calibrated value.

This is just a nice lazy afternoonish quandry, I'd love to hear your thoughts on this.
Thanks,
Marcin

I'm pretty sure you would need more than just some LED's. I used to be an electronics junky back in high school, and I believe what you're trying to accomplish would require a controller of some sort. It would have to be made up of various transistors, caps, resistors, and possible an IC or 2. LED's don't have an exact voltage where they are off or on. You can dim an LED by reducing it's voltage. You can also destroy one if you give it too much voltage. The purpose of a diode is to only allow current to travel in one direction.

I could be wrong about all this however. It has been about 6-7 years since I've messed with any of that stuff. It's a neat idea though, and I am positive something could be home built for way less than $820. Probably sub $100 for everything.