Speed Vest
The Speed-Vest uses ”’Electroluminescent wire”’ and a simple circuit to display a bike riders speed on the back of a hi-vis jacket. Surprisingly cool.
Or better than peggy you could use a TENORI-OFF
I think he only started that project because he had a secret cling film fetish.
I think it’d be easier to adapt EMSs peggy for this purporse, but less comfortable to wear and much more likely to do you damage should you take a spill.
Which means I’m much more likely to do it