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