Developing An Open Source Bike Computer

January 6, 2023 by Bryan Cockfield 46 Comments

While bicycles appear to have standardized around a relatively common shape and size, parts for these bikes are another story entirely. It seems as though most reputable bike manufacturers are currently racing against each other to see who can include the most planned obsolescence and force their customers to upgrade even when their old bikes might otherwise be perfectly fine. Luckily, the magic of open source components could solve some of this issue, and this open-source bike computer is something you’ll never have to worry about being forced to upgrade.

The build is based around a Raspberry Pi Zero in order to keep it compact, and it uses a small 2.7 inch LCD screen to display some common information about the current bike ride, including location, speed, and power input from the pedals. It also includes some I2C sensors including pressure and temperature as well as an accelerometer. The system can also be configured to display a map of the current ride as well thanks to the GPS equipment housed inside. It keeps a log in a .fit file format as well so that all rides can be archived.

When compared against a commercial offering it seems to hold up pretty well, and we especially like that it’s not behind a walled garden like other products which could, at any point, decide to charge for map upgrades (or not offer them at all). It’s a little more work to set up, of course, but worth it in the end. It might also be a good idea to pair it with other open source bicycle components as well.

Thanks to [Richard] for the tip!

Recreating The “Stuck Throttle” Problem On A Toyota

October 30, 2022 by Bryan Cockfield 68 Comments

A few years ago, Toyota was in the news for a major safety issue with a number of their passenger vehicles. Seemingly at random, certain cars were accelerating without concern for driver input, causing many crashes and at least 37 confirmed deaths. They issued recalls both for the floor mats which were reported to have slid forward to jam the accelerator pedal, but this didn’t explain all of these crashes. There was another recall for stuck throttles, which [Colin O’Flynn] demonstrates a possible cause for on his test bench.

While most passenger vehicles older than about 15-20 years controlled the throttle with a cable connected directly from the throttle body to the accelerator pedal, most manufacturers have switched to a fly-by-wire system which takes sensor input from the accelerator pedal and sends that position information to the vehicle’s computer which in turn adjusts the throttle position. This might be slightly cheaper to manufacture, but introduces a much larger number of failure modes to a critical system. Continue reading “Recreating The “Stuck Throttle” Problem On A Toyota” →

Toteable PC Is Inspired By Macs Of Days Gone By

October 14, 2022 by Lewin Day 7 Comments

Back in the 1980s, the personal computer was a hip new thing, and the form this new technology would take was still up for debate. Back then, all kinds of weird clamshells, breadbins, and all-in-one designs hit the market, with the Apple Macintosh proving to be a successful example of the latter. Inspired by the Macintosh 128K that served as their first computer, [Arnov Sharma] decided to whip up a modern all-in-one of their very own.

It’s nicknamed the LATTEintosh, as it’s built around the Latte Panda 3 Delta. This is a single-board computer with an Intel Celeron N5105 CPU, 8GB of RAM, and 64GB of eMMC storage on board. It’s capable of running full-fat x86 operating systems, and here, it’s running Windows 10.

The enclosure is a custom 3D-printed design of [Arnov]’s own creation. It sports a 7-inch HD monitor, fans for cooling, and speakers integrated into the case. Naturally, it’s got a handle on top to make it easy to carry, just like the Macintosh all-in-ones all those years ago.

There’s something to be said for a computer you can just pick up and carry away, and we love the boxy form factor. Sometimes a laptop simply won’t do, and we can imagine many engineers and technicians out there appreciating a build like this. We’ve seen some great all-in-ones before, too. Video after the break.

Continue reading “Toteable PC Is Inspired By Macs Of Days Gone By” →

Building A Replica Of An Obscure Romanian Computer

September 29, 2022 by Lewin Day 5 Comments

We’ve all seen emulated Apple II and Commodore 64 boards about the place. Few of us have heard of the Romanian ZX Spectrum clone known as the Cobra, let alone any efforts to replicate one. However, [Thomas Sowell] has achieved just that, and has shared the tale with us online.

The Cobra was named for its origins in the city of Brasov – hence, COmputer BRasov. The replica project was spawned for a simple reason. Given that sourcing an original Romanian Cobra would be difficult, [Thomas] realized that he could instead build his own, just as many Romanians did in the 1980s. He set about studying the best online resources about the Cobra, and got down to work.

The build started with board images sourced from Cobrasov.com, and these were used to get a PCB made. [Thomas] decided to only use vintage ICs sourced from the Eastern Bloc for authenticity’s sake, too. Most came from the former USSR, though some parts were of East German, Romanian, or Czechoslovakian manufacture. The project took place prior to the Russian invasion of Ukraine, so there weren’t any hassles shipping across borders.

With everything hooked up and the EEPROMs given a real Cobra ROM image, the computer burst into life. There were some hiccups, with an overheating video IC and some memory glitches. However, with some nifty tweaks and replacements subbed in, the computer came good. Other work involved adding a custom keyboard and modifying 3.5″ floppy drives to work with the system.

Overall, the build is a faithful tribute to what was an impressive piece of engineering from behind the Iron Curtain. [Thomas]’s work also embodies the DIY ethos behind many homebrew Cobra computers built back in the day.

If all this talk has got you curious about the full history of the Cobra and Romania’s underground computer movement, we have everything you’re looking for right here!

Pocket Computer Reminds Us Of PDAs

June 23, 2022 by Bryan Cockfield 9 Comments

Before smartphones exploded on the scene in the late 00s, there was still a reasonable demand for pocket-sized computers that could do relatively simple computing tasks. Palm Pilots and other PDAs (Personal Digital Assistants) were all the rage in the ’90s and early ’00s, although for cutting-edge tech from that era plenty of these devices had astronomical price tags. This Arduino-based PDA hearkens back to that era, albeit with a much more accessible parts list.

The build is based around an Arudino Nano with an OLED screen and has the five necessary functions for a PDA: calculator, stopwatch, games, phonebook, and a calendar. With all of these components on such a small microcontroller, memory quickly became an issue when using the default libraries. [Danko] uses his own custom libraries in order to make the best use of memory which are all available on the project’s GitHub page. The build also includes a custom PCB to keep the entire pocket computer pocket-sized.

There are some other features packed into this tiny build as well, like the breakout game that can be played with a potentiometer. It’s an impressive build that makes as much use of the microcontroller’s capabilities as is possible, and if you enjoy projects where a microcontroller is used as if it is a PC take a look at this Arduino build with its own command-line interface.

Continue reading “Pocket Computer Reminds Us Of PDAs” →

Briefcase Computer Is A Glorious Cyberpunk Build

April 2, 2022 by Lewin Day 3 Comments

There are plenty of gaming laptops on the market these days, but none quite fit the requirements of one [ParticularlyPippin]. Thus, they set out on building their own portable computer, ending up with a rig in a briefcase with a decidedly cyberpunk feel.

The design relies on desktop components, with the idea being to make a machine with better upgradability than a typical laptop. The briefcase itself is a nice deep-shell unit, and was given a wooden baseboard to hold all the components. It was then provided with standoffs and mountings for a Mini-ITX motherboard, as well as all the necessary add-ons like fans and storage. As in many odd-form-factor builds, a PCI-E riser cable comes in handy to hook up the GPU.

As for the user interface, a USB portable monitor is paired with a mechanical keyboard for the appropriate amount of clackity-clack when hacking out in the field. The icing on the cake, however, are the RGB strip backlights controlled via MSI’s software that really make the final result pop.

It’s a tidy portable build and one that hopefully provides [ParticularlyPippin] with the necessary grunt for their work wherever they can tote a briefcase. It’s not the first homebrew luggable we’ve seen, and it won’t be the last; there’s simply something compelling about the briefcase form factor. If you’re cooking up your own in the home lab, don’t hesitate to drop us a line.

8-Bit Computer Addresses LEDs

April 19, 2021 by Bryan Cockfield 2 Comments

Homebrew 8-bit computers tend to have fairly limited displays, often one or more seven-segment displays and an array of LEDs to show the values of RAM or perhaps some other states of the computer. [Duncan] is in the process of building just such an computer, but wondered if there was a way to create a more visually appealing display while still keeping the computer true to its 8-bit roots. With some interesting TTL logic he was able to create this addressable RGB LED display to some remarkable results.

The array works by controlling the WS2812B LED strips with a specific timing cycle which was pioneered by [Tim] for a different project. [Tim] was able to perform this timing cycle with some simple Assembly code, which means that [Duncan] could convert that code into TTL gate logic relatively easily. Using 74LS02 NOR chips gets the job done as far as timing goes, and the pulses are then fed into a shift register and support logic which then creates the signal for the LED strips.

When everything is said and done, [Duncan] has a fully addressable 16×16 RGB LED array as a display for his 8-bit computer without violating any of his design principles and keeping everything to discrete TTL logic chips and a stick of RAM. It’s a unique method of display that might go along really well with any other homebrew computer like this one that’s also built with 74LS chips.