Laser Augmented Reality Glasses Show You The Way

July 8, 2021 by 52 Comments

Tech companies like Google and Microsoft have been working on augmented reality (AR) wearables that can superimpose images over your field of view, blurring the line between the real and virtual. Unfortunately for those looking to experiment with this technology, the devices released so far have been prohibitively expensive.

While they might not be able to compete with the latest Microsoft HoloLens, these laser AR classes from [Joel] promise to be far cheaper and much more approachable for hackers. By bouncing a low-power laser off of a piezo-actuated mirror, the hope is that the glasses will be able to project simple vector graphics onto a piece of reflective film usually used for aftermarket automotive heads-up displays (HUDs).

Piezo actuators are used to steer the mirror.

[Joel] has put together a prototype of what the mirror system might look like, but says driving the high-voltage piezo actuators poses some unique challenges. The tentative plan is to generate the vector data with a smartphone application, send it to an ESP32 microcontroller within the glasses, and then push the resulting analog signals through a 100 V DC-DC boost converter to get the mirror moving.

We’ve seen the ESP32 drive a laser galvanometer to play a game of Asteroids, but recreating such a setup in a small enough package to fit onto a pair of glasses would certainly be an impressive accomplishment. Early tests look promising, but clearly [Joel] has quite a bit of work ahead of him. As a finalist for the Rethink Displays challenge of the 2021 Hackaday Prize, we’re looking forward to seeing the project develop over the coming months.

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Tech Hidden In Plain Sight: Cruise Control

July 8, 2021 by 29 Comments

The advent of the microcontroller changed just about everything. Modern gadgets often have a screen-based interface that may hide dozens or hundreds of functions that would have been impractical and confusing to do with separate buttons and controls. It also colors our thinking of what is possible. Imagine if cars didn’t have cruise control and someone asked you if it were possible. Of course. Monitor the speed and control the gas using a PID algorithm. Piece of cake, right? Except cruise control has been around since at least 1948. So how did pre-microcontroller cruise control work? Sure, in your modern car it might work just like you think. But how have we had seventy-plus years of driving automation?

A Little History

A flyball governor from a US Navy training film.

Controlling the speed of an engine is actually not a very new idea. In the early 1900s, flyball governors originally designed for steam engines could maintain a set speed. The idea was that faster rotation caused the balls would spread out, closing the fuel or air valve while slower speeds would let the balls get closer together and send more fuel or air into the engine.

The inventor of the modern cruise control was Ralph Teetor, a prolific inventor who lost his sight as a child. Legend has it that he was a passenger in a car with his lawyer driving and grew annoyed that the car would slow down when the driver was talking and speed up when he was listening. That was invented in 1948 and improved upon over the next few years.

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Bringing The Game Boy Camera Into The 21st Century

July 8, 2021 by 6 Comments

The Game Boy Camera is probably one of the most limited-specification digital cameras to have been mass-marketed, yet it occupies a special position in the hearts of many because despite being a toy with a paltry 128×128 monochrome sensor it was for many the first camera they owned. [Matt Grey] was among those people, and was always frustrated by the device’s inability to export pictures except to the Game Boy printer. So after having bodged together an interface a decade ago but not being happy with it, he returned to the project and made a wireless carrier for the camera that allows easy transfer through WiFi to his mobile phone.

Inside the slab-like 3D-printed enclosure lies a GBxCart RW Game Boy cartridge reader, whose USB port is wired to a Raspberry Pi Zero on which are a set of scripts to read the camera and make its photos available for download via a web browser. At last the camera is a stand-alone unit, allowing the easy snapping and retrieval of as many tiny black and white images as he likes. There’s a video showing the device in action, which we’ve placed for your enjoyment below the break.

This camera has appeared in so many projects on these pages over the years, but we’re guessing that the work on whose shoulders this one stands would be the moment its workings were reverse engineered.

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Electric Land Speed Racing Can Be Lightning Fast

July 8, 2021 by 4 Comments

Land speed racing is a pursuit of ultimate speed above all else. Most cars typically run on huge, flat salt pans, and racers run flat out for miles in a straight line, attempting to push their machines to the limit. Like most motorsports, the history of land speed racing has traditionally been centred around internal combustion, but electric racers have long been out there chasing land speed records as well.

The Need For Speed

At the most famous land speed trials, such as Bonneville’s Speed Week, speed runs take place over miles and miles of open salt, with timing traps along the way to determine competitor’s speeds. These tracks are long enough that acceleration is of little concern, which is of great benefit to electric runners. Additionally, only one or two runs is required to set a record. This means that heavy batteries aren’t always needed, as the distance a competitor must travel is short, and even if the batteries are heavy, it doesn’t excessively affect top speed.

With an eye to that, land speed competitors in electric classes are typically classified into weight classes. This is due to the fact that bigger, heavier battery packs can deliver more current, and thus potentially have a performance advantage over lighter vehicles. Thus, typical classes run by most salt flats competitions involve the E1 class, which allows for vehicles under 1100 lbs, the E2 class, for vehicles up to 2200 lbs, and the E3 class, which is for anything 2200 lbs and above. The FIA also publish their own set of classes, again separated by weight, though to a much more granular degree.

Procedures for setting records vary depending on the venue and the record in question. Local records at salt venues like El Mirage can typically be broken with a single run faster than the standing record, while Bonneville Speed Week competitors must set a higher average speed across two runs on two consecutive days. FIA records differ again, and are perhaps the most stringent, requiring competitors to set a faster average across two runs in opposite directions, set within an hour of each other, to attempt to minimise the effect of wind on the result. Things can sometimes get confusing, as many FIA records, for example, are set at the Bonneville salt flats, but not actually in Speed Week competition or by Speed Week rules. Continue reading “Electric Land Speed Racing Can Be Lightning Fast” →

C64 Demo, No C64

July 8, 2021 by 24 Comments

Never underestimate the ingenuity of the demoscene. The self-imposed limitations lead to incredible creativity, and, the range of devices they manage to get their demos running on never ceases to amaze us. But we never thought we’d see a C64 demo without one central component: the C64.

Full disclosure: [Matthias Kramm]’s demo, called “Freespin”, does need a C64 to get started. The venerable 6502-based computer runs a loader program on a 1541 disk drive.  But from then on, it’s all floppy drive. And [Matthias] has laid bare all his tricks.

The video below shows the demo in full, including a heart-stopping on-camera cable mod. By adding a single 100 Ω resistor, [Matthias] turned the serial clock and data lines into a two-bit digital-to-analog converter, good enough to generate signals for both black and white pixels and the sync pulses needed for the display.

No demo would be complete without sound, and Freespin’s tunes come from controlling the drive’s stepper motor, like a one-voice Floppotron.

Watching nothing but a floppy drive run a cool demo is pretty amazing. Yes, we know there’s a full-fledged computer inside the floppy, but the bit-banging needed to make this work was still mighty impressive. It might be cool to see what you could do with multiple drives, but we understand the minimalistic aesthetic as well. And speaking of tiny little demos:  the 256 bytes of [HellMood]’s “Memories” or [Linus Åkesson]’s “A Mind is Born” still leave us speechless.

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Dial-a-SID Is A Glorious Chiptune Jukebox

July 8, 2021 by 8 Comments

Old-school rotary telephones aren’t particularly useful for their original intended purpose in this day and age, but they’re great fun to hack into new projects. [Linus Åkesson] has done just that, with his Dial-a-SID jukebox build. (Video, embedded below.)

The build installs a Raspberry Pi 3 inside the body of the telephone, running a SID chip emulator and loaded up with the High Voltage SID Collection. The Pi inside outputs sound to an external stereo system for playing chiptunes at a party.

The real party piece, however, is that the handset can be lifted and the telephone dialled in order to listen to and select tracks for the playlist. Tracks can be selected by individual codes, by composer, or even by year. In the event the playlist grows empty, the default behaviour can be set to keep playing random tracks in the meantime.

With over 2000 hours of SID music inside, it’s unlikely the Dial-a-SID will run out of tunes anytime soon. We’d love to see a similar interface used for a jukebox hooked up to a modern streaming service, too. If you build one, let us know! Alternatively, consider hooking up your rotary phone to your smartphone. Video after the break.

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Hamster Trades Crypto Better Than You

July 7, 2021 by 19 Comments

The inner machinations of the mind of cryptocurrency markets are an enigma. Even traditional stock markets often seem to behave at random, to the point that several economists seriously suggest that various non-human animals might outperform one market or another just by random chance alone. The classic example is a monkey picking stocks at random, but in the modern world the hamster [Mr Goxx] actively trades crypto from inside his hamster cage.

[Mr Goxx]’s home comprises a normal apartment and a separate office where he can make his trades. The office contains an “intention wheel” where he can run in order to select a currency to trade, and two tunnels that [Mr Goxx] can use to declare his intention to buy or sell the currency he selected with the wheel. The wheel is connected to an Arduino Nano with an optical encoder, and the Nano also detects the hamster’s presence in the “buy” or “sell” tunnel and lights up status LEDs when he wants to execute a trade. The Nano also communicates with an intricate Java program which overlays information on the live video feed and also executes the trades in real life with real money.

Live updates are sent directly both on Twitter and Reddit, besides the live Twitch stream of [Mr Goxx] we linked above. The stream only shows his office and not his apartment, and he’s mostly active at night (Berlin time). But we can’t wait for his random walks to yield long-term results which can be analyzed for years to come. In the meantime we’ll see if others have been able to make any profits in crypto with any less-random methods.