1980s Toy Robot Arm Converted To Steam And Other Explorations

We were doing our daily harvest of YouTube for fresh hacks when we stumbled on a video that eventually led us to this conversion of a 1980s Armatron robot to steam power.

The video in question was of [The 8-bit Guy] doing a small restoration of a 1984 Radio Shack Armatron toy. Expecting a mess of wiring we were absolutely surprised to discover that the internals of the arm were all mechanical with only a single electric motor. Perhaps the motors were more expensive back then?

The resemblance is uncanny.
The resemblance is uncanny.

The arm is driven by a Sarlacc Pit of planetary gears. These in turn are driven by a clever synchronized transmission. It’s very, very cool. We, admittedly, fell down the google rabbit hole. There are some great pictures of the internals here. Whoever designed this was very clever.

The robot arm can do full 360 rotations at every joint that supports it without slip rings. The copper shafts were also interesting. It’s a sort of history lesson on the prices of metal and components at the time.

Regardless, the single motor drive was what attracted [crabfu], ten entire years ago, to attach a steam engine to the device. A quick cut through the side of the case, a tiny chain drive, and a Jensen steam engine was all it took to get the toy converted over. Potato quality video after the break.

19 thoughts on “1980s Toy Robot Arm Converted To Steam And Other Explorations

  1. I was thinking of connecting my steam engine to one of my armitrons about 15 years ago when I saw a stem conversion on the interwebs that looked very similar to this one. I completey disassembled and reassembled one armitron just to see how it worked — amazing contraption with just one motor plus gears and cams and concentric rods and cylinders for power distribution. Multiple speed even, using cam shifting on each axis for different gear ratios.

    3D printing would still need metal components for power distribution I think — though perhaps carbon fiber might work if friction under load could be managed.

    Here is a teardown:


  2. This was published in Make magazine in May 2006, by Phillip Torrone, in which case it was probably published by him here at hackaday way back then too, though the HaD search is not helping find it…

  3. I used to have one of those and I remember being extremely disappointed when I opened it up and it turned out to be all gears and cams. But, I have to doff my hat (if I actually wore one) to whomever designed the thing– it’s bloody brilliant!

  4. Had an Armatron back in the 80’s. Had a vision of making it computer controlled, opened it up to find nothing but a thousand gears and one motor… I figured trying to control it via the joysticks with servos or something would be pretty lame as I could have just built and arm out of servos and had about the same about of lifting capability (about none).
    Then there was the stupid timer mechanism and the fact that even looking at it the wrong way would cause the sound of gears stripping like a garbage disposal full of utensils.
    Cute toy I guess, but that’s all it was

    1. The mobile version of the armitron had multiple motors – my dad interfaced one to a computer with the parallel port driving relays connected to the control pad. It was my first experience with programming something in the physical world. I was 10, and it was awesome.

      1. I remember those too. I was super jealous when I saw one AFTER getting the armatron. I think it had a big ribbon cable as part of it, giving away the fact there was more than just a single motor in there. AND it was on wheels! I think it was more expensive too, and I was lucky to have the armatron, really.

        No matter now though.. That was 30 years ago and I now own a Eshed SCORBOT arm and linear table that I need to get around to building a controller for. But now I get jealous when I see a fanuc or ABB industrial arm!!!

  5. This morning a friend was helping me go through a pile of stored stuff. “Hey, there’s a robot arm over here in a plastic bag!” And sure enough, it’s my Mobile Armatron (with all the motors and the remote control — yes, connected by a long rainbow ribbon cable), lost for literally over 20 years! Stored without batteries, so no leakage. Looks to be in perfect shape, though I haven’t tested it yet. Tempted to pick up again where I left off with it two decades ago! Here’s the photo from this morning: https://twitter.com/laurenweinstein/status/1146440637115318272/photo/1

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