If development is needed I would rather see the effort go into DIY kits based on arduino and pi devices and cheap (real) sensors. Basically, an extension of what bmengineer has done here with his RuTiTe: RuTiTe - my standalone runtime tester project
Sure, it would be 4-5x the price i’d guess but you would have a device with more functionality and (maybe) better consistency. Some of the costs could be deferred for people who already have compatible boards too.
My .02