ArduRover Boat Uses Tub To Float

August 18, 2019 by Ben James 16 Comments

There’s nothing quite like the sight of a plastic box merrily sailing its way around a lake to symbolise how easy it is to get started in autonomous robotics. This isn’t a project we’re writing about because of technical excellence, but purely because watching an autonomous plastic box navigate a lake by itself is surprisingly compelling viewing. The reason that [rctestflight] built the vessel was to test out the capabilities of ArduRover. ArduRover is, of course, a flavour of the extremely popular open source ArduPilot, and in this case is running on a Pixhawk.

The hardware itself is deliberately as simple as possible: two small motors with RC car ESCs, a GPS, some power management and a telemetry module are all it takes. The telemetry module allows the course/mission to be updated on the fly, as well as sending diagnostic data back home. Initially, this setup performed poorly; low GPS accuracy combined with a high frequency control loop piloting a device with little inertia lead to a very erratic path. But after applying some filtering to the GPS this improved significantly.

Despite the simplicity of the setup, it wasn’t immune to flaws. Seaweed in the prop was a cause of some stressful viewing, not to mention the lack of power required to sail against the wind. After these problems caused the boat to drift off course past a nearby pontoon, public sightings ranged from an illegal police drone to a dog with lights on its head.

If you want to use your autonomous boat for other purposes than scaring the public, we’ve written about vessels that have been used to map the depth of the sea bed, track aircraft, and even cross the Atlantic.

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Adding A Co-Processor To Help SNES Games With Slowdown

August 18, 2019 by Erin Pinheiro 3 Comments

The Super Nintendo port of Gradius III is notable for being close to the arcade original, with its large, bright and colorful graphics. However, due to the limitation of the console’s hardware, the port is also well known for having constant slowdowns during gameplay, particularly during later sections. [Vitor] hacked away at the game and made a patched version of the ROM use a co-processor to eliminate those issues.

The slowdown seen here in Gradius is not uncommon to SNES players, many games of that era suffer from it when several sprites appear on the screen at once. This is partially due to the aging CPU Nintendo chose, supposedly in order to maintain NES backwards compatibility before the idea got scrapped. Unable to complete its tasks by the time the next frame needs to be shown, the hardware skips frames to let the processor catch up before it can continue. This is perceived as the aforementioned slowdown.

Around the later stage of the SNES’s life, games started using additional chips inside the cartridges in order to enhance the console’s performance. One of them is the SA1, which is a co-processor with the same core as the main CPU, only with a higher clock rate. By using it, games had more time to run through the logic and graphics manipulation before the next frame. What [Vitor] did was port those parts of Gradius III to the SA1, essentially making it just like any other enhanced cartridge from back in the day.

Unlike previous efforts we’ve seen to overclock the SNES by giving it a longer blanking time, this method works perfectly on real unmodified hardware. You can see the results of his efforts after the break, particularly around stage 2 where several bubbles fill the screen on the second video.

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Great Artificial Daylight Via Broken TVs

August 17, 2019 by Lewin Day 34 Comments

[DIY Perks] has long been a fan of lights that accurately mimic real daylight. Often choosing high-quality LEDs for his projects, lately he’s taken a different tack – using broken televisions to produce attractive home lighting solutions.

The hack involves removing the backlight from the damaged television or monitor. These have a powerful white light inside, but the real key is that they also features a Fresnel lens. This helps the backlight appear very similar to a real skylight, due to the way it scatters light around the room.

Due to the difficulty of driving most LED and CCFL backlights, the project strips the original lighting out and replaces it with a set of high-CRI LED strips readily available off eBay. These are easily driven from 12 volts and give a white light more similar to actual daylight compared to most backlights. With the LEDs in place, the monitor’s original diffusers and Fresnel lens are put back in place, and the light is finished off with an aluminium frame.

Fitted to an angled ceiling, the light really does look as if actual sunlight is streaming through a window on a rainy day. It’s a pleasant effect that does a great job of lighting a room, and we suspect it would be excellent for general video work, too. [DIY Perks] is no stranger to a good studio light build, after all. Video after the break.

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Enjoy A Refreshing Beverage With The Chilled Drink Calculator

August 17, 2019 by Lewin Day 15 Comments

Hackers are quite often the price conscious type, unwilling to pay jacked up prices for cold beverages when they can be purchased warm and in bulk for much lower cost. However, when guests are on the way and time is running out, it’s crucial to chill the drinks down to the right temperature, and fast. To take the guessing out of the process, [Álvaro Díez] and [Tibor Pal] collaborated to create the Chilled Drink Calculator.

It’s a resource jam-packed full of everything you need to know to get your drinks cold, pronto. Based on heat transfer equations and data from empirical studies, the calculator is able to show you just how long it will take to cool practically any beverage to any temperature. There are presets for different types of container and cooling method, as well as information on the ideal serving temperatures for things like wine, beer and soft drinks. There’s even information on helpful hacks to help cool things down more quickly – with the salt and ice bath being devastatingly effective with minimal equipment requirements.

Keep the calculator in your bookmarks for the next time your pals show up with a case of beer that’s been sitting in the sun all day in the back of a pickup truck (Authors note: looking at you, Terry). Alternatively, consider building an advanced cooling apparatus.

Square Laser Harp Is Hip

August 17, 2019 by Kristina Panos 5 Comments

You know, we hadn’t realized how tired we were of vertical laser harps until we saw [Jonathan Bumstead]’s entry into the 2019 Hackaday Prize. It’s all well and good to imitate the design of the inspiring instrument. But the neat thing about synths is that they aren’t confined to the physics of the acoustic instruments they mimic. This project elevates the laser harp into functional sculpture territory. It’s a piece of art that produces art.

And this art harp is entirely self-contained, with built-in MIDI, amplifier, and speakers. The brains of this beauty are an Arduino Mega and an Adafruit music maker shield, which give it twenty different instrument voices. Each of the six layers has two lasers, two mirrors, and two photo-resistors mounted in the corners of the plywood skeleton. The lasers and photo-resistors are mounted back to back in opposite corners, with mirrors in the other two corners to complete the paths. [Jonathan] cleverly diffused the laser light with milky slivers of film canister plastic.

This isn’t [Jonathan]’s first optical rodeo. Previous experience taught him the importance of being able to readjust the lasers on the fly, because every time he moved it, the laser modules would go out of alignment. This time, he built kinematic mounts that let him reposition the lasers using four screws that each push a corner.

There are a lot of nice touches here, especially the instrument selector wheel. [Jonathan] explains it and the rest of the harp in a fantastic demo/build video that’s just burning a hole in the space after the break.

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Sensor Lets Gestures And An Arduino Control The Tunes

August 17, 2019 by Al Williams 8 Comments

Every time we watch Minority Report we want to make wild hand gestures at our computer — most of them polite. [Rootsaid] wanted to do the same and discovered that the PAJ7620 is an easy way to read hand gestures. The little sensor has a serial interface and can recognize quite a bit of hand waving. To be precise, the device can read nine different motions: up, down, left, right, forward, backward, clockwise, anticlockwise, and wave.

There are plenty of libraries to read it for common platforms. If you have an Arduino that can act as a keyboard for a PC, the code almost writes itself. [Rootsaid] uses a specific library for the PAJ7620 and another — Nicohood — for sending media keys.

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NFC Business Cards To FPGA Cubes, Skull Badges To Bandoliers, Here’s The Hardware From Breakfast At DEF CON

August 17, 2019 by Mike Szczys 5 Comments

We had our biggest Breakfast at DEF CON ever on Sunday. So big, in fact, that the carefully laid plans went awry immediately.

This is the fifth year we’ve hosted the event, which kicks off the final day of DEF CON with some hardware show-and-tell. We really thought we had it all figured out, since this time we actually booked a space in Paris hotel. For the first three years we were just banditing the space — asking everyone to show up at this place and it’ll become an event. Last year we planned to have it in the Hardware Hacking Village, but the casino stopped us from bringing in pastries that morning and we ended up camping out in a dining area that wasn’t open until the afternoon.

Last weekend we had a cafe booked, with pastries and coffee on order. The only problem is that you are all too awesome. We had a couple hundred people show up and the cafe didn’t want us standing, which limited our space to the number of booth seats available. No worries, as is the tradition we spilled out into a lounge area on the casino floor and enjoyed ourselves!

Here’s some of the hardware that showed up at this gathering.

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