Just cadence, please
 

I have a low-cost Echowell Echo V-2 Cycling Computer and am happy with its simple & useful level of function.

I would like to add a second device to display cadence. What is a simple and reliable device to consider?

Michael

If you don't find a device, you could always just remember what speed equals what cadence in certain gears. After a while you'd have a good intuition what an 80 rpm or 90 rpm or 100 rpm cadence feels like.

Here's a website that'll show you the relationship between speed and cadence for your gearset:

http://www.hostelshoppe.com/tech_gearcalc.php

My old computer didn't provide cadence function so I taped a printout from Sheldon Brown to my stem to give me a clue.

If you want another device to just read out cadence this is the way to go: instructable