Electric Vehicles On Ice

August 16, 2019 by 10 Comments

This winter, a group of electric vehicle enthusiasts, including [Dane Kouttron], raced their homemade electric go-karts on the semi-frozen tundra nearby as part of their annual winter tradition. These vehicles are appropriately named Atomic Thing and Doom Sled, and need perfect weather conditions to really put them to the test. You want a glass-like race track but snowfall on ice freezes into an ice-mush intermediate that ends up being too viscous for high-speed ice vehicles. The trick is to watch for temperatures that remain well below zero without snow-like precipitation.

The group is from the community makerspace out of MIT known as MITERS and already have EV hacking experience. They retrofitted their VW Things vehicle (originally built for a high speed electric vehicle competition) to squeeze even more speed out of the design. Starting out with an 8-speed Shimano gearbox and a 7kW motor, they assembled a massive 24S 10P battery out of cylindrical A123 cells salvaged from a Prius A123 Hymotion program. This monster operates at 84V with a 22AH capacity, plenty for power for the team to fully utilize the motor’s potential.

The battery is ratchet strapped to the back of the Atomic Thing to provide more traction on the ice. It must feel just like riding on top of a different kind of rocket.

Original configuration of battery packs
Battery packs ratchet strapped

They tried using ice skates in the front of the Atomic Thing, but the steering was difficult to control over rough ice. Studded solid tires perform quite well, resulting in less jarring movement for the driver. Doom Sled is a contraption built from a frame of welded steel tube and a mountainboard truck with ice skate blades for steering. The motor — a Motenegy DC brush [ME909] — was salvaged from a lab cleanout, transferring power to the wheels through a chain and keyed shaft. The shaft-to-wheel torque was duly translated over two keyed hub adapters.

Doom Sled with seat strapped on

The crew fitted a seat from a longscooter and made a chain guard from aluminum u-channel to keep the flying chain away from the driver’s fingers. The final user interface includes a right-hand throttle and a left-hand “electric brake” (using resistors to remove the stored energy quickly to combat the enormous inertia produced by the vehicle).

Overall, ice racing was a success! You can see the racing conditions were just about perfect, with minimal ice mush on the lake. Any rough patches were definitely buffered smooth by the end of the day.

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Turning A Sony Into A Leica Through Extreme Camera Modding

August 16, 2019 by 13 Comments

The quality of a photograph is a subjective measure depending upon a multitude of factors of which the calibre of the camera is only one. Yet a high quality camera remains an object of desire for many photographers as it says something about you and not just about the photos you take. [Neutral Gray] didn’t have a Leica handheld camera, but did have a Sony. What’s a hacker to do, save up to buy the more expensive brand? Instead he chose to remodel the Sony into a very passable imitation.

This is a Chinese language page but well worth reading. We can’t get a Google Translate link to work, but in Chrome browser, right clicking and selecting “translate” works. If you have a workaround for mobile and other browsers please leave a comment below.

The Sony A7R is hardly a cheap camera in the first place, well into the four-figure range, so it’s a brave person who embarks on its conversion to match the Leica’s flat-top aesthetic. The Sony was first completely dismantled and it was found that the electronic viewfinder could be removed without compromising the camera. In a bold move, its alloy housing was ground away, and replaced with a polished plate bearing a fake Leica branding.

 

Extensive remodelling of the hand grip with a custom carbon fibre part followed, with significantly intricate work to achieve an exceptionally high quality result. Careful choice of paint finish results in a camera that a non-expert would have difficulty knowing was anything but a genuine Leica, given that it is fitted with a retro-styled lens system.

We’re not so sure we’d like to brace Leica’s lawyers on this side of the world, but we can’t help admiring this camera. If you’re after a digital Leica though, you can of course have a go at the real thing.

Thanks [fvollmer] for the tip.

Fire Breathing N64 Puts Blast Processing In The Shade

August 15, 2019 by 10 Comments

Consoles over the years have innovated, bringing new features and experiences with each subsequent generation. Rumble, motion controls and more recently VR have all come to the fore as companies vie for supremacy in the marketplace. Nobody’s really had the guts to tackle fire, though. Until now.

The case and spinning logo alone would have made the front page; the fire is simply next level. Our parents were always telling us to sit further from the TV… and now we know why.

The build is based on the Nintendo 64. The motherboard is removed from the original case, and fitted to a sheet metal enclosure of impressive craftsmanship. This allows the fitment of the machine’s party piece — twin jets of flame, triggered by an extra button on the controller. There’s also a spinning N64 logo built into the front of the case, backlit in a foreboding red — hinting to the player that this is no regular console.

The console is capable of shooting flames up to 4 feet long, and if you have to ask why, you’re likely on the wrong website. We’d love to see the jets triggered by rumble, ideally on a per player basis — making bouts of Mario Kart and Smash Brothers more perilous than ever.

As it turns out, fire’s also a great way to visualise sound waves. Video after the break.

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LED Driver Board Could Be Your Ticket To FPGA Development

August 15, 2019 by 19 Comments

Microcontrollers are a great way to learn about developing for embedded systems. However, once you outgrow their capabilities, FPGAs bring muscle that’s hard for even the fastest-clocked micros to match. If you’re doing anything with high-speed signals, loads of RAM, or something that requires lots of parallel calculation, you can’t go past FPGAs. Dev boards can be expensive, but there are alternatives. There’s a nifty project on Github trying to repurpose commodity hardware into a useful FPGA development platform.

Chubby75 is a project to reverse engineer the RV901T LED “Receiver Card”. This device is used to receive signals over Ethernet, and clock data out to large LED displays. This sort of work is highly processor intensive for microcontrollers, but a cinch for FPGAs to manage. The board packs a user-reprogrammable Spartan 6 FPGA, along with twin Gigabit Ethernet ports and 64MB of SDRAM. Thanks to the fact that its firmware is not locked down, it has the potential to be repurposed into all manner of other projects. The boards are available for under $30 USD, making them a prime target for thrifty hackers.

Thus far, the team have begun poring through the hardware documentation and are looking to develop a toolchain to allow the boards to be easily reprogrammed. With the right tools, these boards could be the next thing in cheap FPGAs, taking over when the Pano Logic thin clients become thin on the ground.

[Thanks to KAN for the tip!]

Bike-Mounted Synthetic-Aperture Radar Makes Detailed Images

August 15, 2019 by 20 Comments

Synthetic-aperture radar, in which a moving radar is used to simulate a very large antenna and obtain high-resolution images, is typically not the stuff of hobbyists. Nobody told that to [Henrik Forstén], though, and so we’ve got this bicycle-mounted synthetic-aperture radar project to marvel over as a result.

Neither the electronics nor the math involved in making SAR work is trivial, so [Henrik]’s comprehensive write-up is invaluable to understanding what’s going on. First step: build a 6-GHz frequency modulated-continuous wave (FMCW) radar, a project that [Henrik] undertook some time back that really knocked our socks off. His FMCW set is good enough to resolve human-scale objects at about 100 meters.

Moving the radar and capturing data along a path are the next steps and are pretty simple, but figuring out what to do with the data is anything but. [Henrik] goes into great detail about the SAR algorithm he used, called Omega-K, a routine that makes use of the Fast Fourier Transform which he implemented for a GPU using Tensor Flow. We usually see that for neural net applications, but the code turned out remarkably detailed 2D scans of a parking lot he rode through with the bike-mounted radar. [Henrik] added an auto-focus routine as well, and you can clearly see each parked car, light pole, and distant building within range of the radar.

We find it pretty amazing what [Henrik] was able to accomplish with relatively low-budget equipment. Synthetic-aperture radar has a lot of applications, and we’d love to see this refined and developed further.

[via r/electronics]

Home Automation At A Glance Using AI Glasses

August 15, 2019 by 3 Comments

There was a time when you had to get up from the couch to change the channel on your TV. But then came the remote control, which saved us from having to move our legs. Later still we got electronic assistants from the likes of Amazon and Google which allowed us to command our home electronics with nothing more than our voice, so now we don’t even have to pick up the remote. Ushering in the next era of consumer gelification, [Nick Bild] has created ShAIdes: a pair of AI-enabled glasses that allow you to control devices by looking at them.

Of course on a more serious note, vision-based home automation could be a hugely beneficial assistive technology for those with limited mobility. By simply looking at the device you want to control and waving in its direction, the system knows which appliance to activate. In the video after the break, you can see [Nick] control lamps and his speakers with such ease that it almost looks like magic; a defining trait of any sufficiently advanced technology.

So how does it work? A Raspberry Pi camera module mounted to a pair of sunglasses captures video which is sent down to a NVIDIA Jetson Nano. Here, two separate image classification Convolutional Neural Network (CNN) models are being used to identify objects which can be controlled in the background, and hand gestures in the foreground. When there’s a match for both, the system can fire off the appropriate signal to turn the device on or off. Between the Nano, the camera, and the battery pack to make it all mobile, [Nick] says the hardware cost about $150 to put together.

But really, the hardware is only one small piece of the puzzle in a project like this. Which is why we’re happy to see [Nick] go into such detail about how the software functions, and crucially, how he trained the system. Just the gesture recognition subroutine alone went through nearly 20K images so it could reliably detect an arm extended into the frame.

If controlling your home with a glance and wave isn’t quite mystical enough, you could always add an infrared wand to the mix for that authentic Harry Potter experience.

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Spain’s First Open Source Satellite

August 15, 2019 by 27 Comments

[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.

The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.

The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.

Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.

The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.

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