Laserjohn

I got it used, but all the parts are there. Since I'm a techie, I wanted to test it out before installing. So I was planning on writing a LabVIEW program to send proper 'sending unit' signals to the cluster to make sure all my LED's work.

Does anyone know on a 1980 what the "sending units"...send? Or the signals may come from the computer directly... I'm looking for the signals for the water temp gauge, Oil pressure, fuel gauge, and Alternator sense. I can literally send any type of voltage/ low-current, or pulses to the cluster. I can figure out the calibrations, but I'm looking to find out if it's in the range of milli-volts, milli-amps, volts?

Thanks!

The13Bats

I cant help much with the tech you need but in general,

The old ones cyberdyne, noskog, javelin thats all that comes to mine, ,

in the early days used gm senders but sometimes oddball one year, one make and model,

The speedo was a transducer idea,

Most didnt have amp gauge but rather volts so thats easy and most used gm fuel sender 0 – 90Ω
but read out percent of fuel left, like 80 means 80% left,

I might try common gm then ford sender signals to start with,

Richard454

The senders- really don't send any signals- they just see the variance of resistance to ground.


example-

The13Bats

I just used a figure of speech "signal" same as the op did,

Thanks for clearing that up, mental note made....

Bikespace

You can probably dummy the tach and digital speedo (if it has that) with square waves via LabView and some hardware. I'd use an Arduino, since the hardware is MUCH cheaper than anything from National Instruments, but if you have an investment in parts already, it sounds like a fun project. Keep the current low for this, unless you can find the specs online.

As Ernie Willcox pointed out (and other diagrams at his excellent site confirm), the gauge "senders" are actually variable resistance grounding pathways. There is another fixed resistor inside the gauge (perhaps adjustable, to calibrate, when possible), that acts as a voltage divider circuit to run the needle. This basically sets the current and voltage within the "sender" unit. A power supply and a potentiometer or a resistor decade box should be all you need to test most of the gauges. I'd expect to see the same reading whether you were at 12V or 14.5V, but you might want to test that too.

It looks like Willcox has all of the diagrams and sender specs that you would need if you use the stock Corvette senders.

Please post photos of your test setup when you get all the gauges working!

The13Bats

I cant tell you what senders but i do recall some of the early made for corvette dash digital kits didnt always use orginal corvette senders...

Some of the kits the word or legend for what it was like "oil" it wasnt really spelled out in led but rather a plastic cut out over a light to appear it was led with real leds just used for the varible read out part of the gauge, i believe the first cyberdyne javelin ones were like that,

indy99

I just purchased one of these... http://www.ebay.com/itm/C3-Corvette-...hVN-a8&vxp=mtr

I will install in the spring. As far as senders, you can use your originals or use theirs.

Laserjohn

That looks exactly like the one I have, however, yours has the latest PCB material (Probably FR4), mine is ancient. I will get another piece of smoked lexan, that was the only thing that looked dingy...

Laserjohn

I use LabVIEW all the time for work, and since I have it installed on my laptop, I'll just borrow one of the DAQ units from work for this. If the gauges are just variable resistors to GND, then it is likely that it is a 'current', I'll look for a voltage regulator somewhere on the kit, unless I find one that will dump the 12V to 5V or 3.3V, then I'll use the 12V as supply. Cool, I'll try to get this done by next week!