A digital dash is cool and all ... Instead, this build is an analog display for GPS-acquired speed data. The video below does a good job at explaining the basics of [Grant Stephens]’ build.

You can listen in on a two meter repeater and you can build a GPS module speedometer. That’s what [Jeremy Cook] did with just a few parts, a little 3D design, and some handy zip ties to hold it ...

Surely the GPS technology should be more accurate than the speedometer? – RP You’re right that GPS is usually more accurate ...

"What is the most accurate speed indicator - analogue speedometer, digital speedometer or GPS on sat navs?" - LE Dear LE, Vehicle speedometers, whether digital or analogue, calculate speed based ...