Professional cable cams are expensive, but you can make your own for your smartphone with this children's toy for dirt cheap. (And it kinda works.)
Camera movement is super important if you want to make your smartphone film projects look professional, right? There are many tools out there that can help you move your phone's camera smoothly, from mini-tripods to handheld gimbals, but if you want to save some money, you might want to take a look at this DIY build from Dave Knop (a.k.a. knoptop).
He found a children's toy, more specifically a "Tin Can Cable Car", that looks a lot like a smaller, plastic version of a pro-grade cable cam, and retrofitted it so he mount his smartphone to it. Check out the video below to see it in action.
I mean, knoptop's DIY smartphone cable cam is pretty cool, but admittedly, it only kind of works the way you'd want it to. Depending on the kind of cable/rope/string/fishing line you use, you're going to experience a lot of stretch and sag, as well as camera shake...which is the exact opposite of what you're looking for when using a camera movement tool.
However, after making some alterations to the build, like switching out velcro straps for an adjustable smartphone mount and using fishing line rather than thread, he was able to get some decent hyperlapse shots. And for a toy that costs as low as $10 (I saw it on Amazon for $11-$16), it's not too bad. Clearly a plastic toy with a little motor isn't going to carry and move your camera like a $400 cable cam, but...I mean...it works. It can withstand the weight of a phone and moves it from Point A to Point B.
Maybe there are other adjustments you could make to the build to solve the "cable" issue that causes shaky footage, and if you can think of one, share it down in the comments.