I have hit a bit of a roadblock on my latest project. I am trying to use an Arduino to drive the Speedometer and Tachometer from a 92 Acura Legend. I purchased the dashboard from E-bay, and dismantled it to find that the gauges are actually controlled via 3 contacts marked SIN/COM/COS. I had assumed incorrectly that the gauge was a simple spring resistance volt meter. Frustrated I sent the whole project aside...

I was able to find this:

http://www.onsemi.com/pub/Collateral/CS8190-D.PDF

But have been unable to find the chip for sale (for a reasonable price).

So here I ask for some help, I simply do not know where to begin. I get the feeling that this is not going to be as simple as driving the SIN and COS point with but I really don't know.

Any direction provided would be much appreciated.