LEGO Technic and the Commodore 64 – Part VI

During the Christmas season I found the time to create another project from the book published in 1985 entitled “Make And Program Your Own Robots for the Commodore 64 and VIC-20” I started blogging about here.

I skipped the project called “Card Reader”, some kind of punch(ed) card reader able to translate holes punched in a piece of cardboard into binary code. Maybe I will try that some other time.

This time I created the Mini Arm project. It requires two 4.5V motors and some pretty intricate wiring. I made a copy of the page and used different color felt tip pens to make the schema more readable, as shown below.

Wiring Schema

This time two homemade switches were needed, again constructed using a paperclip, some tinfoil and a small rubber band, as seen in Part V.

Two Switches

The Commodore 64 BASIC program belonging to this project has a “Teach Moves” mode and a “Repeat Moves” mode. While in Teach Mode the keys 1 and Q make the arm turn and keys 2 and W make it go up and down. At the end of each move press key S to save that particular move.

Below are some videos of the working arm. We start with an overview and end with some LEGO brick lifting.


2 thoughts on “LEGO Technic and the Commodore 64 – Part VI

  1. You did well to get those paperclip-and-rubberband switches to work reliably!
    Mine were a disaster (I made the ZX Spectrum interface) – I found the wires kept falling out of the foil-covered pin and the paperclip – and also, the switch just didn’t make a reliable enough contact (despite a few efforts to ‘debounce’ in software). I guess you could say “all part of the fun” but when finally getting it working after 30+ years of wanting to, it was a surprise how awful it was!

    1. Thanks for your comments, Alex. I did not have this book as a child and bought it online (second hand) in 2015, 30 years after publication. Recently I saw on a LEGO event the Dutch version of the book as well. So it must have been in stores at that time in the Netherlands were I live. And I remembered my father telling me in the 80s about the possibilities to control LEGO Technic with a Commodore 64. But at that time I was afraid to damage/fry/melt my beloved toy so never looked into those possibilities. It must have been this book he was talking about, I guess now… So I am catching up…

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