I ordered a Cateye Velo 8 bicycle computer from Amazon.com. It arrived today at work, so I installed it before my ride back to my car.
I had estimated the distance to 6 miles, and the Cateye measured it as 5.91 miles. I rode that distance in 32 minutes. It’ll be neat to compare different routes, and my average speeds.
Don’t take this as an endorsement of the product. The last time I saw a speedometer on a bike it was mechanical. I haven’t kept up on bicycle technology, and even the lowest-end stuff seems cool to me.