Yes, this is somewhat of a re-post from something I posted over a year and a half ago, but I think it got lost in the shuffle (more likely posted in the wrong place), and now that the BHS now has a social media ninja, I figured it'd less likely get lost (and more likely I'd be informed of just why this idea had no responses previously).
In the last year, there's a been a handful of handheld 3-axis gimbals hit the market such as Feiyu's G4 Series; there was even a kickstarter version (that was probably just an importer). These really don't seem all that uniquely difficult, especially for someone who has access to a CNC machine, laser cutter, and multiple 3D printers. 3 motors, an accelerometer or two, some sort of processor (not sure how involved it is, I'm assuming a simple microcontroller can handle everything), power, and the housing to hold it all.
Some things to think about:
Single handed use
Try to make the loading of the recording device single handed as well?
Maybe some simple controls for Bluetooth or USB connections to phone (additional app required?) for starting/stopping recording
All the commercial devices are for either GoPro and/or smart phones; is this for marketing reasons or because a 300 gram cheap (ish) handheld camcorder weighs too much for the motors that are used in these devices? Can we make the mounting generic enough to handle a GoPro, Smartphone, or a Camcorder?
Depending on how big this thing is going to be, should/could there be any consideration for moving on the 3 axes (as opposed to simply rotating on the axes), even if only a couple inches. Normally this is achieved with the mounting harness for an M56 Smart Gun, a.k.a. a steadicam vest.
All the various modes: no yaw compensation, eased yaw compensation, and total yaw compensation (the camera totally fixed on a point).
Maybe include some degree of Soloshot type tracking abilities, though using a maybe a simple IR emitter/receivers?