Earlier than video video games, there have been pinball machines. Not that they don’t exist right this moment, however a contemporary pinball machine will doubtless have microprocessors and different fancy issues that conventional pinball machine designers may by no means dream of. [Eli] had certainly one of these mechanical machines from 1974 as a child and, later, encountered a extra fashionable machine with a rudimentary microprocessor and different built-in circuits onboard. One factor this enabled is the flexibility to recollect excessive scores. However it’s a must to bodily take a look at the machine, and you’ll solely see the highest 4 scores. [Eli] determined to adapt the machine to add excessive rating knowledge to the Web, and it’s a enjoyable undertaking.
[Eli]’s design objectives have been to make it automated and sturdy. That’s, if the community is down or the machine loses energy, you shouldn’t lose excessive rating knowledge. As well as, he didn’t need to change the looks or injury the 40-year-old machine. You possibly can see a video of the way it all turned out beneath.
The Laser Cue machine is certainly one of many constructed across the “Williams System 7” platform. A 6808 CPU, together with some I/O chips to handle all of the lights, sensors, and bells. The sport has solely 1K of RAM, 12K or ROM, and 128 bytes (no prefix, simply bytes) of RAM with battery backup. There was even a typical “working system” referred to as Flipper ROM, and that’s really documented over on GitHub.
Because the reminiscence for the machine is all in exterior chips, it was an affordable concept to interchange the CPU with a board that monitored indicators on the board. The CPU would plug into this new board, after which a more moderen microcontroller with an Web connection may snoop on bus visitors. Nonetheless, eradicating the previous CPU and jamming pins into the traditional socket was worrisome, so as an alternative, [Eli] elected to faucet right into a take a look at connector that was already on the board however not plugged into something.
An ESP32 is greater than able to the speeds, though connecting to five V logic was a little bit of an issue. The CPU has 5 V tolerant pins, however a number of the 25 out there pins on the event board both set objects on boot or could briefly be outputs and have been thus unusable. To scale back the required pins, [Eli] determined to do a number of the decoding in separate logic. As an alternative of utilizing TTL chips, he elected to make use of a programmable logic array.
After that, it appeared it could be easy, however there was one thing stopping the ESP32 from studying every bus cycle. [Eli] by no means bought to the underside of it however as an alternative switched to the Raspberry Pi Pico W. Utilizing the chip’s particular I/O processors made the job straightforward, and it labored completely. The remainder of the undertaking was simply match and end. You should definitely learn to the top to seek out out the teachings realized which could make it easier to in your subsequent related undertaking.