Commodore Tape Drive Emulator On A Raspberry Pi

December 17, 2019 by Tom Nardi 23 Comments

We imagine most of the people reading Hackaday have an old Raspberry Pi or two laying around. It’s somewhat less likely you’ve still got an 8-bit Commodore in working condition, but we’d wager there’s more than a few in the audience that can count themselves among both groups. So why not introduce them?

[RhinoDevel] writes in to tell us about CBM Tape Pi , an open source Commodore tape drive emulator for Raspberry Pi that needs only a handful of passive components to get wired up. Even better, the project targets the older Pis that are more likely to be languishing around in the parts bin. In the video after the break, a Commodore PET can be seen happily loading content from the original Raspberry Pi with its quaint little composite video connector.

Without any special software on the Commodore itself, the project allows the user to load and save PRGs on the Pi’s SD card, as well as traverse directories. Don’t expect stellar I/O, as [RhinoDevel] notes that no fast loader is currently implemented. Of course if you’re enough of a devotee to still be poking around a VIC-20 or C64 this far into 21st century, then we imagine you’ve got enough patience to get by.

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An Open Source Boating Autopilot With Some Custom Tweaks

December 17, 2019 by Lewin Day 11 Comments

Piloting a boat is all well and good, but can get dull when you’d rather be reclining on the deck with a cold beverage in hand. For [Timo Birnschein], this simply wouldn’t do. He began to gather parts to put together an autopilot to keep his boat on the straight and narrow.

The build is based around OpenPlotter, which uses a battery of marine-ready software to handle routing charts, autopiloting, and providing a compass heading for navigation. Naturally, it all runs on a Raspberry Pi. In combination with PyPilot, it can be used to let the vessel drive itself around a series of waypoints, allowing you to soak up the atmosphere on the water without having to constantly steer the craft.

[Timo] ran into some issues, however, with the hardware side of things. Existing implementations for motor control to drive the rudder weren’t quite cutting it, so the system was reworked to run with a robust H-bridge and some fresh Arduino code. This was combined with a custom rudder sensor built with a potentiometer and some 3D printed gears. Future work aims to double up the rudder sensors for redundancy, something we should all consider at times.

Overall, the system is starting to come together, and [Timo]’s enjoying letting his boat think for itself. He notes that it’s very important to keep an eye on the boat while operating in this condition, lest it veer off course – many a boat has been lost this way. We’re always supporters of a mature attitude towards autonomous vehicle operations!

Reverse Engineering An Old Bus Display

December 11, 2019 by Tom Nardi 14 Comments

When his makerspace was gifted a pair of Luminator LED signs of the sort you might see on the front of a bus, [PWalsh] decided to pull one apart to see what made it tick. Along the way, he managed to reverse engineer its control protocol and replace its original control board with a WiFi-connected Raspberry Pi. Now they can use the LED signs to show whatever they want; no bus required.

As they were designed for automotive use, the signs were wired for 12 volts DC. So the first order of business was fitting it with an AC/DC converter so it could be plugged into the wall. After he measured the display’s current consumption, [PWalsh] estimated it’s maximum energy consumption and determined an old ATX computer power supply was more than up to the task.

With the sign happily running battery-free, he could begin figuring out how to talk to it. Noticing a MAX485 RS-485 converter on the PCB, gave a pretty good idea of what language it was speaking, and with the aid of his trusty oscilloscope, he was able to suss out the baud rate. A cheap USB to RS-485 converter was then wired in between the sign and its control board so he could sniff the data passing over the line.

From there, the final piece of the puzzle was studying the captured data and figuring out the protocol. [PWalsh] was able to identify packet headers and ASCII characters, and pretty soon knew enough about how the sign communicated that he was able to remove the control board entirely and just push text and images to it right from the Pi. He’s even made his framework available for anyone else who might have a similar piece of bus-signage laying around.

Even if you’re not looking to add one of these signs to your lab, this project is a fantastic example of protocol reverse engineering with low-cost tools and simple techniques. We always love to see the process broken down step by step like this, and our hat’s off to [PWalsh] for delivering the goods in a big way.

This isn’t the first time we’ve seen these sort of LED signs get the “Internet of Things” treatment, and if you’re content with a somewhat scaled down version, you could always just build your own display rather than waiting on the local public transit vehicle to get parted out.

Not-Quite-So-Hot Stuff: A Thermal Exam On The Latest Raspberry Pi

December 6, 2019 by Jenny List 53 Comments

When the Raspberry Pi 4 was first launched, one of its few perceived flaws was that it had a propensity to get extremely hot. It’s evidently something the Pi people take very seriously, so in the months since they have addressed the problem with a set of firmware updates. Now they’ve taken a look at the effect of the fixes in a piece on the Raspberry Pi web site, and it makes for an interesting comparison.

The headline figure is that all updates together remove about a watt of power from the load, a significant quantity for what is still a board that can run from a capable phone charger. Breaking down the separate parts of the updates is where the meat of this story lies though, as we see the individual effects of the various USB, memory, power management and clocking updates. In temperature terms they measure an on-load drop from 72.1 °C to 58.1 °C, which should be a significant improvement for any Pi 4 owner.

There is a debate to be had over in what role a computer such as a Pi should serve. As successive revisions become ever more desktop-like in their capabilities, do they run the risk of abandoning the simplicity of a cheap Linux box as a component that makes us come back for more? It’s a possibility, but one they have very well addressed by developing the Pi Zero. They have also successfully avoided the fate of the Arduino — inexorably tied to its ATmega powered original line despite newer releases. As we have frequently said when reviewing Raspberry Pi competitors, it’s the software support that sets them apart from the herd, something this power-draw story demonstrates admirably.

1984 WeatherMan Pi Shows The Ch-Ch-Ch-Ch-Changes

December 5, 2019 by Kristina Panos 8 Comments

When [MisterM]’s MIL gave him a rad 80s portable cassette player, he jumped for joy. Once he figured out the window was exactly the same size as the standard for Raspberry Pi HATs, the possibilities left him reeling. A flurry of ideas later, he settled on a weather display featuring a Pimoroni Unicorn HAT HD.

The 1984 Weatherman Pi pulls data from the Dark Sky API every 1.5 seconds using a Zero W. [MisterM] chose to highlight the current temperature, conditions, and rain probability, though there are heaps of other API goodies still on the table. It shows the current weather conditions as animations, scrolls the temperature, and gives a nice graph of rainfall probability.

Surprisingly, the dazzling display isn’t our favorite part. See those spongy headphones up top? They’re not just for decoration, though they go a long way in helping the cassette player keep its identity. Whenever there’s a change in the weather, they shimmy back and forth on a 9g servo. If the servo were continuous, it might be neat to use them as a weather vane.

Be sure to check out [MisterM]’s comprehensive demo/build video waiting for you on the B-side. We love a good weather display around here, and the more colorful and literal, the better.

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A Thermal Typewriter For Burning Thoughts

December 5, 2019 by Kristina Panos 15 Comments

There’s a certain charm to old technologies that have been supplanted by newer versions. And we’re not just talking about aesthetic nostalgia this time. With older versions of current technology, you are still connected to the underlying process, and that’s a nice feeling.

Part of the typewriter’s charm is in its instant permanence. These days, its so easy to backspace, delete, and otherwise banish thoughts to the void without giving them a fair trial, though it’s nice not to have to pound the keys to make an impression. At the typewriter, your words are immediately committed to paper, for better or worse. You can usually see them pretty well, although maybe not on the current line, and that is good for letting the words flow without judgment.

[Murtaza Tunio] recently used a thermal POS printer in an art project, but it had since grown cold with disuse. Why not turn it into a typewriter? All it took was a Raspberry Pi, a USB keyboard, and an existing Python library for communicating with these parallel printers. Typing is a bit challenging for a few reasons. For one thing, [Murtaza] has to type five lines before the words become visible. The enter key doesn’t come across for some reason, so a different one had to be assigned. On the upside, [Murtaza] can trigger the paper cutter with a keystroke.

Not too hot on thermal printers? You might find this e-ink typewriter refreshing.

Building A Faux Retro Portable Computer

December 1, 2019 by Tom Nardi 48 Comments

The modern laptop has its origins in the mid to late 1980s, when shrinking computer hardware and improvements to battery technology finally made mobile computing practical. But before the now iconic clamshell form factor became the standard, there was a market for so-called “portable” computers. These machines often resembled pieces of luggage with keyboards attached, and even at their peak, they were nowhere near as practical as today’s ultra-thin notebook computers. But for the more nostalgic among us, these vintage portables do have a special sort of charm about them.

Looking to recapture some of that magic with modern components, [davedarko] has started working on his own Raspberry Pi portable computer. Just like those machines of yore, his build is designed to be a self-contained computing experience that you can lug around, but not exactly something you’d be popping open on the train. Its extruded aluminum frame holds the display, power supply, and audio hardware, with plenty of room to spare for additional hardware should he decide to pack in a couple hard drives or something more exotic.

The skeletal frame has plenty of room for activities.

We particularly like the 3D printed hinge and lock mechanism he designed that holds the keyboard closed against the front of the frame. Sufficiently ~~old~~ experienced readers will recall this particular feature being a defining characteristic of portables such as the Osborne 1 and Compaq Portable, and it’s great to see it included here. All it needs now is a leather handle on the side to complete the look.

[davedarko] still has some work ahead of him, as ultimately he’d like to completely enclose his computer’s frame with laser cut panels. But the build is certainly progressing nicely, and frankly, it’s already at the point where we’d have no problem pulling it out at the next hackerspace meetup. Between builds like this and the growing collection of cyberdecks we’ve covered recently, it looks as though 1980s design aesthetic is alive and well within the hacker community.

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