Robots.net reader hmatos noticed a new toy in the Discovery Channel's
Spark line. "The Armatron is back ! The Discovery Channel store is
selling a robotic arm called Spark that looks identical to the old Radio
Shack Armatron with the exception of a new green color scheme." Yes,
it's bright green, has a few minor cosmetic changes and it's called the
Robot Arm but most people will immediately recognize it as the old
distributed by Radio Shack in the 1980s. Many a robot builder started
out with an Armatron and was amazed by the single motor driving all the
joints through a bizarre system of gears. Surprisingly, the new Spark
Robot Arm retails for $30, not much more than you'd spend buying a vintage
Armatron on eBay.
The gearing system in that first version of the Armatron is amazing. Obviously plastic gears were cheaper than separate motors. This arm was not easily interfaced to a PC, but the second version had a motor in each axis and was. Mine still has a DE9 connector hanging off it :)
I'd like to ba able to drive so much stuff with one gear, I'm having a hard time trying to figure out something to do with my NXTbot, and it's got 3.
I was thinking of putting an Armatron (or I guess it could be a Spark now) on my mobile robot project as a cheap way to give it some manipulation capability. There doesn't seem to be another robot arm out there for lest than several hundred dollars. Does anyone have a good feel for how strong the Armatron is and if hacked, how precisely it could be controlled through a PC?
In all fairness there does appear to be a lack of really good affordable arms on the market at the moment. You can buy a mobile robot thats quite good, but you cant easily get an arm for it.
There are some good things out there like the OWI007 or the Lynxmotion kits, but they have their own limitations. Whats lacking is something that run on DC, is affordable, has a fair payload capacity, can be mounted any way and can be easily interfaced to.
If I remember correctly the Armatron is not easily hacked for a number of reasons. (1) the joysticks are mechanically linked (not contact switches or pots as you'd hope) making it difficult to interface to a computer, (2) The joints have no position feedback (The wrist just turns and turns) so a computer wouldn't know each joint's positions and it's hard to do a position reset, (3) There's only one motor so it's not just a matter of controlling all the motors, you have control the linkages too. So, to control it, you'd likely have to add servos to control the linkages and you'd have to add motor control circuitry and feedback circuitry, hack it all up, and after all that you could have bought a nicer system that was built for it and ready for it and wasn't so difficult. If you're thinking about hacking this thing, this isn't the arm you're looking for. It's really too bad that there is not a cheap robot arm solution. For example, Lynxmotion.com has arms that interface well, but they start at about $300.