Welcome to my instructable on animatronic hand building.
Addition to the section on the crank shaft build!
Addition to the section on the fingers
addition to the section on tumbling
I was going for a rough industrial look from a bygone era. Solenoids and servo's are the easy way to go, and would not fit the part. Neither would arduino processors or other digital controllers give me that analog feel i was after. A tuned crankshaft complete with push/pull rods, air-craft cable and chunky steel makes for an old school feel and sound. I'd call it steampunk-ish, but vintage pre-industrial post Russian is more apt.
Originally this was going to be a replica build of the hand and arm displayed in the terminator movies at Skynet. But, then i wanted it to move. I was still going for the look of a statue/display model, but at the same time I wanted it to be interactive. A couple of years back I built a robotic salmon for the local museum complete with infrared camera eye, monitor display and articulating mouth fins and body. All of these could be controlled by the patrons themselves. Interactive art is the new black.
This build does take into account that the builder can weld and has access to a welder. Of course this could all ways be built with using rivets or nut and bolt, but would be need to be thought out a bit more. I'm sure one could use alternate metals too, I used aluminum rod for the fingers and thumb, and the balance out of recycled bits of steel. Total cost for this was about 30$, with the biggest cost being the aluminum 17$. These were scrap, but when buying metal such as this they charge by the pound regardless if it came from there scrap bin. The rest was used up buying washers, odds and ends, air craft cable and the brass connectors.
This instructable has been a while in the making. All though the total combined hours wasn't that great, the space of 30 minute intervals stretched it out over a month. Total time was about 16 man hours.
Last but not least, safety. Working with metal will make you bleed, its gonna happen. Be careful, its one thing to get small cuts from metal (which you will) its another to have a penetrating eye wound from flying disintegrating zip cut discs. Where full face shield masks, ear protection and watch where your body is in relation to killer tools at all times!
Finally, if you do build this, be ready for the "Big bang theory jokes" I would put an actual video of the episode below, but... the powers that be at youtube would frown on that. So... just copy and past the following!
Have a look, and please remember to VOTE and take the time to rate me. Thanks and enjoy!
Here is the hand running on a test motor, a 12 volt automotive motor. This would be much too fast and loud for a permanent display, but still its awesome!
Here it is finished, much slower but I love the articulation.