29 thoughts on “Building Your Bots The 1980s Way

  1. “and interfacing to them was a bit more challenging than the easy-to-use GPIOs of their modern counterparts.” Nonsense. Most of the ancient 8-bit computers made their address and data buses available for hacking, making it a trivial matter to add I/O ports, and their BASIC interpreters had “peek” and “poke” instructions that made the software side equally trivial. How are “modern” GPIOs easier?

    1. Having made interfaces for a vic 20 to control disco lighting and used modern micro controllers to control all manner of things I have to disagree with your asset assertation BBJ.

      yes the databus was available and it was easy enough to poke a value etc. but one needed a way to decode the address bus and include a latch to hold the data, Sure it wasn’t difficult but increased the component count somewhat. So to drive 8 240v lights took 8 optocouplers and triacs. A few logic gates for he address and a latch to hold the data. On top of the Vic20

      Now it just the optocouplers, triacs and 1 micro ( of your preferred flavour). To drive some servos you only need the micro.

      1. These are examples of COMPLICATED interfaces, in my mind. What you need for GPIO is an address decoder, consisting of a 13-input NAND gate, and enough inverters to handle all of the zeros in your address (or you could use an XOR on each address line with a dipswitch or set of jumpers to select the address) for address decode (decoding the high 13 bits, so the port shows up on eight consecutive addresses), one 8-bit latch for outputs and another (with tri-state outputs) for inputs, and a couple more 2-input NANDs to translate the read and write signals from the CPU into latch pulses and output enables. We’re talking five chips for the version with a hard-coded address, or another three chips if you want to dipswitch-select the address.

        I never had an Apple ][ when they were being built (too expensive), but I was constantly adding crap to my TRS-80 Color Computer, and it was child’s play.

        I think when people think of the “bad old days” when personal computers ware difficult to hack, they’re thinking of the days of ‘386 processors and later, which ran programs in protected mode, taking away your ability to easily access the I/O ports, and also of the dark times when serial and parallel ports disappeared, displaced by the opaque USB interface. It’s only since microcontrollers have been available in cheap dev kits (and Arduinos) with high-level language compilers that we’ve RETURNED to the light days of easily accessible computing devices.

      1. Yes! This is what I’m talking about. We had cheap computers we could program in high-level language that could easily connect to external hardware in the 1980s. That all went away in the 90s because everything had to be protected mode on our super-desktop-computers, which meant that GWBasic and peeks and pokes became unsupportable. Sure, there were microcontrollers available throughout, but no cheap high-level compilers for them. It was only when somebody came up with a platform with simple, cheap hardware and free, high-level software — Arduino — that we finally got back to what had been declared obsolete. Isn’t it great how Microsoft and Apple knew better than us what we needed?

        Of COURSE today’s computers are far superior to what we had in the 80s. But it was as if somebody invented the automobile and then declared that we no longer need bicycles!

    2. Let me see. Interface to a Raspberry Pi or Arduino: hook up to a GPIO and go.

      Interface to my Sinclair ZX81: make a port with a set of latches and a load of address decode logic, a bunch of 74 chips.

      I think “A bit more challenging” sums that up nicely. Not impossible by any means, but as I said, a bit more challenging.

  2. Holy cow! Capsela! I had a few of those kits when I was a kid in the late 80’s. I can explain why they didn’t stick around: They were so cool that you had to have them, but they wouldn’t stay together, or wouldn’t come apart! And the little couplers could go missing pretty easily, and the gear box made bad sounds with anything but minimal torque. They were awesome and kinda horrible at the same time. Lego Technics were much better. Then again, Legos didn’t come with pontoons! You can still buy capsela-like kits on Amazon: http://amzn.to/2g1RGzr

      1. I never had the spheres break, but the cuplers sure did! Became just lose enough that you could put it together, but then it would self destruct when you over-torqued it. Then again, I used to pack it back and forth to school and use the wind gauge to dig holes in the long-jump pit, so it probably took some abuse.

  3. My grandparents bought me a capsula kit when I was about 6. That sparked a love electronics and mechanics that got me where I am today. It was probably the most mentally stimulating toy I had growing up.

      1. Think I owned one of those for a few years, but all it ever did was decorate a shelf. It was during that awkward period, when all support for them had disappeared from computer stores, and they were too obsolete for the internet, until retro movements really took a hold, (Seriously it was an e-desert out there for older systems until into the 2000s, was too old to have got on the net when it was current, and there was only spammed out newsgroups that cared.)

  4. We had capsella at infant school, my first experience of controlling motors was using that back in the 80s. Late I used to do robotics on an atari 600xl. The computer was small enough to mount on top of a moving platform. It could be run from a 6v lead acid battery, read analogues (kindof) through the paddle pins and drive I/Os from the joystick. On the 65Xe you could just about drive motors from the cassette SIO interface using poke 54018,52.

  5. Apple II machines literally had GPIO in them, in the form of the game port on the motherboard. It’s a 16 pin DIP socket that includes digital outputs, digital inputs, and analog inputs. Connecting the outside world to these machines is very easy. People did (and do) it all the time.

      1. Atari 400 and 800 machines also had GPIO-like connections in their joystick ports. The inputs could be reconfigured as outputs, which was a cool and little-known feature. The VIC-20 had the User Port that was very flexible, giving you direct access to the configuration(input and output) of the VIA pins, so it was also literally GPIO. The C-64 was less easily interfaced with, providing “only” address and data bus access on both the User Port and Cartridge Port. That would require latching and decoding, as others have said.

        1. C64 user port is DATA only, no external latching required
          $dd03 direction
          $dd01 gpio

          plus two 16 bit counters up to 1MHz, plus 4x analog and 2×4 bit input from joystick ports.
          C64 was pretty loaded when it comes to easy interfacing. All around great computer. Google gives interesting book report from 1985 about using c64 in a lab:
          https://books.google.pl/books?id=LoXNCgAAQBAJ&pg=PA52&lpg=PA52&dq=c64+cia+timers+frequency+khz

          Jenny Sinclair kid :))). There were good expensive computers, computers with great value for money, and Spectrums with as much(little) value as 40 quid got you. You have to love ingenuity that conceived shipping computers with half the ram broken.

  6. Yet no mention of Erector or Meccano. Capsela? Expensive. Limited. LEGO (Technics) was and still is Awesome though pricey.
    Yup them old 8bit got abused and was easier with BASIC. But slow. Often starting with BASIC and quickly moving to embedded Assembler to squeeze a little more subMIPS juice. Tortured parallel ports abounded. Commodore’s built in user port; 6522 torture at its finest. Documentation with schematics made hackable and seemingly proportional to likelyhood of survival. Oooops IBM leaked their ISA card interface. Infer what u will. Apple put it point blank in users manual. Nice fold out.
    We made them bots larger is all. Often more than 20lb beasts rolling around crunching toes bruising shins, and chipping drywall equally well. Big deep cycle marine batteries or refurb aircraft NiCd. Microcontrollers were available 8032/52,8047, 68HC11 and variants of those mostly. KIM was nice cheap 6502. 8052 sported a TinyBASIC too but ya mostly assembler and macro assemblers. Wouldn’t refer to Apples as ‘cheap’. Reasonably priced maybe until they swelled big headed. I have seen a few Apple I/II Bots. Last one was called “WOZ” but it t(r)ailed a 120vAC line.
    Heathkit HERO I being the most famous. Alpha arm for Apple. Omnibot. RB5X. A Slew of ‘Turtles’. Here: http://www.theoldrobots.com/

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