cool the thing l made is working out pretty nice --- trying to fine tune the falling rate of the rig is the hard part -- and for the rig l made, taking the pulleys off so l can remove the whole thing from the line is a little tricky trail-side. you might want to add weight so it doesn't rock from side to side

 just thinking --- l think one large pulley might be a great option as well as two smaller pulleys ----with mine (a 2 pulley design), as you pull the cage up the zine line, you see the cage and how it tilts up along with the slope of the zip line --- using one large pulley, the body of the cage will always remain in a straight vertical line. (aka the camera will remain level) l have another prototype l will dismantle and rebuilt as a single pulley design. ----- using a design similar to you PVC pipe design, you might be able to mount on of those GoPro "tri pod" mounts at the bottom..... hmmm, l think l could ever design one with a tri-pod mount at the top of the pulley, using a U shape bracket that wraps over the pulley. that would be dope --- rollin' two Go-Pro at the same time -- one facing foward, one facing backward (filming multiple riders, riding at the same time).

 my best version to date from my bag of tricks ---

dual pulley set up the way they are, in-line with a small gap between the two allows me to move it from one zip line to the next without any fuss --- just turn the carriage 90o and slip the cable through the two pulleys, rest it on the line and taa-daa. zip line ready.


www.pinkbike.com/u/PedalShopLLC/album/TSFs


SIDE NOTE -- some other guys are trying to build similar things, making them as light as possible --- personally, l think a little added weight is key -- at least with the type of zip line l'm using it is --- the added weight helps keep the rocking motion down and helps with the falling/rolling speed. gravity fed, light weight units slow down too quickly.

 here's some zip line testing with the new rig l made small changes to---


gotta tweak it just a tad but, it's really easy to set up.


there's a quick wobble each time you release the unit but the wobble goes away within about 6 feet of rolling.


www.pinkbike.com/u/PedalShopLLC/channel/GoPro-Zip-Line-fiddlin

 2nd, revised version ---

aside from the GoPro and pulleys, it's 100% left-over bike parts


www.pinkbike.com/photo/8724930

 That looks awesome!! post how it goes and i might have to nab your design !!!

 Nice, now you need cable and a steep hill...You riding yet?

 one pulley design:


www.pinkbike.com/photo/9034527

 cool

 super cool brother!