An old style magnet-on-the-spokes job would give you “Speed”/”Distance” while on the turbo. I’m guessing that’s what Bez’s Sigma is?
If you wanted to spend more, you could get a GPS unit, which would allow you to follow and record routes when you get out and about. Fancier ones have bigger screens so you can see maps as well as just an outline of the route.
But for that to work on the turbo, you’d need a unit that works with ANT+ bluetooth, so it can pick up signals from a speed sensor (magnet on the spokes), available for purchase separately. The separate speed sensor costs more than Bez’s Sigma, and is of limited use when you’re out and about as the GPS positioning is doing that job already.
So you may as well get Bez’s Sigma for now, and research GPS computers between now and spring. You could do that while you’re on the turbo! 😀
NB: nedrapier is in no way in no way associated, linked or affiliated with Bez or Bez’s spares bin.