This is a cool gps based app that works pretty damn good. At least at night, not so much in the daytime. I have it on an old smartphone I don't use anymore. Thought I would share.
Look up Speedview on the Android Play Store.
It has many options of what you can display on screen. It also has a windshield HUD mode. I currently have mine set up to display my current speed, distance traveled, what direction I am traveling relative to a 360 degree circle, and what elevation I am currently traveling at.
Kind of cool. Does it only display speed?
Velcro phone?