3D Print Your Very Own Mechanical Computer

November 10, 2019 by Bryan Cockfield 30 Comments

Most Hackaday readers are familiar with computers from the 70s and 80s, but what about ones even older than that? The Digi Comp 1 was a commercially available computer from the 1960s that actually cost less than a modern-day microcontroller. The catch? It was mechanical rather than electrical. Thanks to retro-wizard [Mike Gardi], now anyone can build a replica of one.

Admittedly the Digi Comp 1 was more of a toy than a tool, but it was still a working computer. It contained three flip-flops (memory) and had a lever that acted as a clock, allowing the user to perform boolean operations and some addition and subtraction. Certainly not advanced, but interesting nonetheless. [Mike]’s version of the Digi Comp 1 has an extra bit when compared to the original and includes some other upgrades, but largely remains faithful to the original design.

If you want to print one of these on your own, [Mike] has made all of the files available on Thingiverse. He has also experimented with other mechanical computers as well, including the sequel Digi Comp 2. We’ve seen some recent interest in that mechanical computer lately as well.

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An Atari Graphics Chip, Ready For You To Build

November 10, 2019 by Jenny List 27 Comments

The most notable of the home computer and console hardware from the 8-bit golden era didn’t get their impressive sound and graphics from off-the-shelf silicon, instead they relied on secretive custom chipsets to get the edge over their competitors. Unfortunately for vintage gaming aficionados, those chips are now long out of production and in many cases there’s little information to be had about their operation.

Which makes discovery of the schematics (PDF link) for the “Tia Maria” graphics chip found in the Atari 7800 console an unusual occurrence, and one which should be of special interest to the emulation community. They can be found alongside the rest of the Atari Museum’s 7800 information.

That such a useful document is available at all is due to a lucky find in a dumpster following the demise of Atari, when a treasure trove of documents was discarded. It seems that the existence of these schematics has been known within the Atari community for some time, and we expect before long this information will find its way into FPGA implementations of the 7800; especially since the system features nearly complete backwards compatibility with the massively successful Atari 2600.

When that happens we hope we’ll be able to bring it to you, but it’s not the first time someone’s made an Atari on an FPGA.

Via RetroRGB

Header image: Bilby [CC BY 3.0]

Accessibility Apps Get Help From Bluetooth Buttons

November 10, 2019 by Al Williams 4 Comments

Ever hear of Microsoft Soundscape? We hadn’t, either. But apparently it and similar apps like Blindsquare provide people with vision problems context about their surroundings. The app is made to run in the background of the user’s mobile device and respond to media controls, but if you are navigating around with a cane, getting to media controls on a phone or even a headset might not be very convenient. [Jazzang] set out to build buttons that could control apps like this that could be integrated with a cane or otherwise located in a convenient location.

There are four buttons of interest. Play/pause, Next, Back, and Home. There’s also a mute button and an additional button you can use with the phone’s accessibility settings. Each button has a special function for Soundscape. For example, Next will describe the point of interest in front of you. Soundscape runs on an iPhone so Bluetooth is the obvious choice for creating the buttons.

To simplify things, the project uses an Adafruit Feather nRF52 Bluefruit board. Given that it’s Arduino compatible and provides a Bluetooth Human Interface Device (HID) out of the box, there’s almost nothing else to do for the hardware but wire up the switches and some pull up resistors. That would make the circuit easy to stick almost anywhere.

Software-wise, things aren’t too hard either. The library provides all the Bluetooth HID device trappings you need, and once that’s set up, it is pretty simple to send keys to the phone. This is a great example of how simple so many tasks have become due to the availability of abstractions that handle all of the details. Since a Bluetooth HID device is just a keyboard, you can probably think of many other uses for this setup with just small changes in the software.

We covered the Bluefruit back when it first appeared. We don’t know about mounting this to a cane, but we do remember something similar attached to a sword.

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Blackjack Game Plays With The Limits Of PyPortal

November 10, 2019 by Kristina Panos 4 Comments

It’s that time of year again, when fall is quickly ushered out to make room for all things holiday-related. For many of us, this means going on trips to visit relatives, which, depending on the relatives, can mean soul-crushing boredom. [Andy] has fun relatives who frequent the casino tables, and they inspired him to brush up on his blackjack game.

Some people would just find a virtual blackjack table or bust out an actual deck of cards to practice, but this is Hackaday. [Andy] busted out his PyPortal and tried his hand at making a blackjack game. The PyPortal is an Adafruit IoT box that makes it easy to scrape and display all kinds of JSON goodness from around the web, like NASA’s image of the day. GUI building is already baked in, so he just needed some oome open source playing card images and he was off.

The real gamble here might be the code he wrote; at 500+ lines, [Andy]’s probably pushing his luck with the PyPortal. But you know what they say — you can’t win if you don’t play. And if you want to improve your odds of winning, teach a robot to count cards for you.

Thanks for the tip, [foamyguy].

Finally, A Usable Rotary Phone From A Conference Badge

November 9, 2019 by Jenny List 2 Comments

A few weeks ago we featured a project from [Dan], a work-in-progress in which he was attaching an EMF 2018 electronic conference badge to a rotary phone. At the time we looked forward to his progress, expecting maybe to see it in our travels round the field at EMF 2021. We have to say we did him a disservice then, because he’s made excellent progress and has now turned it into a fully functional cellular rotary phone.

When we left him he’d interfaced the dial to the badge and not a lot else, but it was enough to spark our interest because we think there should be more re-use of old electronic conference badges. Since then he’s reverse engineered the original bell with the help of a motor driver and a cheap DC-to-DC converter, and the handset with the guts of a Bluetooth headset because in experimenting he managed to kill the badge’s audio circuitry.

The result can be seen in the video below the break, and we have to admit it looks pretty good. Depending where you are in the world you’ll either love or hate the ringing sound, but that is of little consequence to the utility of the device. If you have a drawer full of conference badges gathering dust, perhaps it’s time to give them a second look.

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Just How Simple Can A Transceiver Be?

November 9, 2019 by Jenny List 20 Comments

We’ve frequently talked about amateur radio on these pages, both in terms of the breadth of the hobby and the surprisingly low barrier to entry. It’s certainly the case that amateur radio does not have to mean endlessly calling CQ on SSB with an eye-wateringly expensive rig, and [Bill Meara N2CQR] is on hand with a description of a transceiver that’s so simple it only uses one transistor.

It’s a 40 meter (7 MHz) QRP or low power transceiver in which the transmitter is a simple crystal oscillator and the receiver is an equally simple regenerative design. What makes it so simple is the addition of a three-way switch to transfer the single transistor — a J310 FET — between the two halves of the circuit. It’s no slouch as QRP radios go, having clocked up real-world contacts.

This circuit shows us how a little can go a long way in the world of amateur radio, and we can’t help liking it for that. It’s worth saying though that it’s not without flaws, as a key click filter and another transistor would make for a much higher quality transmitted signal. But then it would no longer be a single-transistor rig, and thus would miss the point, wouldn’t it.

The Rotodyne Fails To Take Off

November 9, 2019 by Al Williams 45 Comments

Bacon and eggs, chocolate and peanut butter, salt and pepper; some things just go together. You’d think that a mashup of an airplane and a helicopter would be great, right? The Fairey Rotodyne was just such a thing from the late 1950s and while it looked to be the wave of the future, it never took off — at least, not in the business sense at least. [Mustard] has an excellent video about the machine including some flight footage and explains why it failed to take over the aviation market. You can watch the video below.

While it does look like a helicopter mated with an airplane, it’s actually a bit different. The rotor isn’t normally powered at all. However, it does turn in forward flight and generates about half the lift the plane needs. That explains the stubby wings. The topside rotor has small jets at the tips that can be used during vertical take off, landing, and hovering modes.

For its time, it was fast and efficient, especially compared to contemporary helicopters. This type of plane was known as an autogyro and actually appeared in the 1930s as a safety mechanism since an autogyro can land in an autorotation mode.

According to the video, the noisy tip jets and production delays killed the beast. There was only one prototype built, but there was something we found very attractive about it. There have been, of course, other autogyros. British, German, Japanese, and Russian military have used autogyros at one time or another. The United States Postal Service was known to employ at least one.

Even today, there are about a thousand autogyros used by different military and police organizations. They are cheaper than a helicopter to buy and fly. Sadly, though, it doesn’t look like autogyros will ever become a common sight. Like an airship, they seem like a callback to an earlier time when you have a chance to spot one.

We are always surprised we don’t see more model autogyros. We wonder how they’d be at cutting down trees.

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