Electronic Device to get speed data
For those not familiar, the Crossfire has an automatic spoiler that comes up at 60mph and goes back down at somewhere around 20mph.

I am wanting to integrate something similar as I customize the Vette.
I plan to use a wing like this one and have it either simply raise up, or preferably cantilever up like the Crossfire spoiler.

I am hoping to score a Crossfire spoiler assembly from a junkyard car. The mechanical part I think I can conquer, my problem is getting a dry contact or other signal that I can use to control a relay to raise and lower the wing at 60mph and 20mph respectively.
Is anyone aware of a device such as a wheel sensor that I could install to give a signal at a preset or adjustable speed that I could use to trigger my wing actuators?








