Objective - to make a manipulator remotely controllable over the internet. There were almost no problems with software and electronics, but mechanics proved to be troublesome. There are simply no relatively cheap manipulators for sale at affordable prices, no matter hat you do. We found several kinds of manipulators on foreign sites, but we didn't feel like buying a piece of hardware for a considerable sum of money since we were not fully sure its capabilities fit all our needs. There photographs and descriptions of the manipulators, there are even videos, but still some details that interest us are not entirely clear. So we decided in favour of a cheaper solution for the experiment - we bought a construction kit. For this purpose we used the open source manipulator OR-LC-ARM-v2, the pieces for which can be found on Roboforum. The kit comes only with polycarbonate pieces and tiny screws. Servo drives, metalware, screws, and nuts are not included. Within a couple of nights the manipulator was assembled, connected to Arduino, and tested.
The load capacity is quite good (it easily lifts and holds a quite large screwdriver). But problems surfaced - the structure had turned out to be not rigid enough, it's just plastic parts after all. When testing control over network (remotely, via the internet) the claw grabbed the edge of the table several times, almost breaking. Another problem is that the servo drives get quite noticeably heated when the claw holds an object in the raised position. One HXT10k servo died - it just burned. Just for this reason we had to postpone testing the manipulator control en masse (yeah, from Habrahabr). For in the case of an invasion by a crowd of people the claw would not have lasted long, and constantly substituting the servos was not a very happy perspective. So now were are in the stage of finding a suitable manipulator arm with a rigid structure. In general, the control interface for the claw can be found here - http://virt2real.ru/roboarm. This is a technical section for debugging. More information about the claw can be found in a blog on g0l.ru. And here are some videos of how we built and tested the claw.