Made myself a gopro wire cam thingamy at work on the 3d printer when no one was looking, idea was i wanted something small enough to fit into a camelbak, light enough to use 1-2mm 'wire' and with some sort of speed limiter, without using friction on the line (makes a racket and gives a bumpy shot). Designed with the limitations of the printer in mind, so not the sexiest thing ever, but started off like this...
That middle wheel can be adjusted up and down, idea being that the more of an angle you bend the line (some parachord i found) through the slower it would go.
It changed a bit along the way, figured i could get the same result from the centre wheel by moving it left and right, as it would up and down, also the original camera attachment was fucking awful idea so i simplified that to use two ball/socket joints clamping together with a single captive bolt. Its about 250g all in.
First test flight, wasnt expecting it to go this fast...
https://www.youtube.com/watch?v=laMjo1FC7OISo the 3rd wheel bendy wire thing does work, it'll slow it by about 25%, but thats about it, you bend it further and it makes the trolley unstable, its not anywhere near enough of a braking force for what i need..
Anyone here got any ideas? I can make pretty much anything within reason, a cylindrical fan like a turbo trainer might do it, but it would have to be reasonably large, or geared up with some sort of pulley arrangement to increase its speed, maybe there's something simple i can do with magnets, rubber bands, etc....