There’s some good detail in [Aliaksei]’s translated post on the “Only Paper” forum, a Russian site devoted to incredibly detailed models created entirely from paper. [Aliaksei] starts with the basic building blocks of logic circuits, the AND and OR gates. Outputs are determined by the position of double-headed pistons in chambers, with output states indicated by pistons that raise a flag when pressurized. The adder looks complicated, but it really is just a half-adder and full-adder piped together in exactly the same way it would be wired up with CMOS or TTL gates. The video below shows it in action.
If [Aliaksei]’s name seems familiar, it’s because we’ve featured his paper creations before, including this working organ and a tiny working single cylinder engine. We’re pleased with his foray into the digital world, and we’re looking forward to whatever is next.
The aptly named [Clickity Clack]’s new YouTube channel promises to be very interesting if he can actually pull off a working computer using nothing but relays. But even if he doesn’t get beyond the three videos in the playlist already, the channel is definitely worth checking out. We’ve never seen a simpler, clearer explanation of binary logic, and [Clickity Clack]’s relay version of the basic logic gates is a great introduction to the concepts.
Using custom PCBs hosting banks of DPDT relays, he progresses from the basic AND and XOR gates to half adders and full adders, explaining how carry in and carry out works. Everything is modular, so four of his 4-bit adder cards eventually get together to form a 16-bit adder, which we assume will be used to build out a very noisy yet entertaining ALU. We’re looking forward to that and relay implementations of the flip-flops and other elements he’ll need for a full computer.
Add some feedback to an original NES controller by making it vibrate. This feature is often known as Rumble Pak, a controller add-on for the Nintendo 64 which vibrated as a game feature. This version adds a small DC motor (in the upper right) with a screw soldered off-center to the motor shaft.
[Andy Goetz] and his friend built this as a robot controller, taking advantage of the latch and clock pins. Normally, nothing happens while both pins are held high, a signal that they easily patched into using an AND gate. This is actually a neat find, as the addition of an internal microcontroller could add bi-directional communication when the latch is high and the clock is strobed.