Wireless Charging Without so Many Chargers

[Nikola Tesla] believed he could wirelessly supply power to the world, but his calculations were off. We can, in fact, supply power wirelessly and we are getting better but far from the dreams of the historical inventor. The mainstream version is the Qi chargers which are what phones use to charge when you lay them on a base. Magnetic coupling is what allows the power to move through the air. The transmitter and receiver are two halves of an air-core transformer, so the distance between the coils exponentially reduces efficiency and don’t even think of putting two phones on a single base. Well, you could but it would not do any good. [Chris Mi] at San Diego State University is working with colleagues to introduce receivers which feature a pass-through architecture so a whole stack of devices can be powered from a single base.

Efficiency across ten loads is recorded at 83.9% which is phenomenal considering the distance between each load is 6 cm. Traditional air-gap transformers are not designed for 6 cm, much less 60 cm. The trick is to include another transmitter coil alongside the receiving coil. By doing this, the coils are never more than 6 cm apart, even when the farthest unit is a long ways from the first supply. Another advantage to this configuration is that tuned groups continue to work even when a load changes in the system. For this reason, putting ten chargeables on a single system is a big deal because they don’t need to be retuned when one finishes charging.

We would love to see more of this convenient charging and hope that it catches on.

Via IEEE Spectrum.

Manhole Covers Hide Antennas

5G is gearing up to be the most extensive implementation of mesh networking ever, and that could mean antennas will not need to broadcast for miles, just far enough to reach some devices. That unsightly cell infrastructure stuck on water towers and church steeples could soon be hidden under low-profile hunks of metal we are already used to seeing; manhole covers. This makes sense because 5G’s millimeter radio waves are more or less line-of-sight, and cell users probably wouldn’t want to lose connectivity every time they walk behind a building.

At the moment, Vodafone in the UK is testing similar 4G antennas and reaching 195 megabits/sec download speeds. Each antenna covers a 200-meter radius and uses a fiber network because, courtesy of existing underground infrastructure. There is some signal loss from transmitting and receiving beneath a slab of metal, but that will be taken into account when designing the network. The inevitable shift to 5G will then be a relatively straightforward matter of lifting the old antennas out and laying the new hardware inside, requiring only a worker and a van instead of a construction crew.

We want to help you find all the hidden cell phone antennas and pick your own cell module.

Via IEEE Spectrum.

Use Your Game Boy As A Wireless Controller

Like many retro favourites, the Game Boy is in no way dead — development continues apace through its many fans.But what about the hardware side? This is a particularly interesting one: [Alex] wondered if a Game Boy could be readily used as a wireless controller. Set out to make it happen, the final product is a game cartridge that makes the classic handheld a wireless controller.

It’s achieved quite elegantly, with a custom cartridge used to turn the Game Boy into a controller while requiring no modification to the handheld. The cartridge contains a flash chip to store the ROM, along with an ATmega48PA microcontroller and an NRF24L01 to do the talking. Upon powerup, the Game Boy runs code from the ROM, and the microcontroller is in charge of reading button states and sending them to the NRF24L01 for transmission. The program stored on the ROM also allows configuration changes to be made from the Game Boy itself, such as choosing the appropriate wireless channel.

The cartridge transmitter can be used with a variety of receivers. [Andy] has developed a USB HID joystick emulator to allow the Game Boy to be used with PCs, as well as a receiver for the GameCube, too. Yes, that’s right — you can now play Super Smash Bros. with a weirder controller than all your friends. A Super Nintendo version is also in the works. Perhaps the coolest feature, however, is that the cart can use its radio link to communicate with another Game Boy running the same cartridge. [Andy] demonstrates this with a basic game of Pong being played between two Game Boy Advances.

Working on retro hardware can be great fun — things are well documented, parts are cheap, and there’ll be plenty of fans cheering you on, too. [Andy] has even made the hardware available for purchase on Tindie and his website if you’re not quite comfortable rolling your own.

The Game Boy platform remains ripe for hacking – you can even take screenshots with a logic analyzer these days. Video after the break.

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RFID Doing More than ID

RFID is a workhorse in industrial, commercial, and consumer markets. Passive tags, like work badges and key fobs, need a base station but not the tags. Sensors are a big market and putting sensors in places that are hard to reach, hostile, or mobile is a costly proposition. That price could drop, and the sensors could be more approachable with help from MIT’s Auto-ID Lab who are experimenting with sensor feedback to RFID devices.

Let’s pretend you want to measure the temperature inside a vat of pressurized acid. You’d rather not drill a hole in it to insert a thermometer, but a temperature sensor sealed in Pyrex that wirelessly transmits the data and never runs out of power is a permanent and cheap solution. The researchers have their sights set on glucose sensing and that news come shortly after Alphabet gave up their RFID quest to measure glucose through contact lenses. Shown the top of this article is a prototype for a Battery Assisted Passive (BAP) RFID sensor that uses commodity glucose testing strips, sending data when the electrochemical reaction occurs. It uses six of these cells in parallel to achieve a high enough peak current to trigger the transmission. But the paper (10.1109/RFID.2018.8376201 behind paywall) mentions a few strategies to improve upon this. However, it does prove the concept that the current spike from the test strips determines the time the tag is active and that can be correlated to the blood glucose detected.

How many of our own projects would instantly upgrade with the addition of a few sensors that were previously unobtainable on a hacker budget? Would beer be brewed more effectively with more monitoring? How many wearables would be feasible with battery-free attachments? The sky is the figurative limit.

Thank you, [QES] for the tip [via TechXplore]

HD Video and Telemetry Link Uses Standard WiFi Hardware

[GlytchTech] decided to implement his own Digital Data Link (DDL) for his drone experiments, and by using a Raspberry Pi Zero and some open-source software, he succeeded in creating a mostly self-contained system that delivers HD video and telemetry using an Android phone as a display.

USB tethered Android phone used as a display and touch interface.

The link uses standard WiFi hardware in a slightly unusual way to create a digital data link that acts more like an analog system, with a preference for delivering low latency video and a graceful drop-off when signal quality gets poor. A Raspberry Pi Zero, Alfa NEH WiFi card, external antenna, battery, and a 3D printed enclosure result in a self-contained unit. Two are needed: one for each end of the link. One unit goes on the drone and interfaces to the flight controller, and the other is for the ground station.

A companion android app allows for just about any old Android phone to serve as video feed, on-screen display of telemetry data, and touchscreen interface.

The software is DroneBridge (GitHub repository) and it implements Wifibroadcast which uses WiFi radios, but without the usual WiFi functionality. A Raspberry Pi is the usual platform, but there’s also an ESP32 port. The software is capable of even more, but so far suits [GlytchTech]’s needs just fine, and he was able to refine his original Watch_Dogs-inspired hacking drone with it.

Organic Ornithopter Sensor Drone

Bees. The punchline to the title is bees carrying sensors like little baby bee backpacks. We would run out of fingers counting the robots which emulate naturally evolved creatures, but we believe there is a lot of merit to pirating natural designs, but researchers at the University of Washington cut out the middle-man and put their sensors right on living creatures. They measured how much a bee could lift, approximately 105 milligrams, then built a sensor array lighter than that. Naturally, batteries are holding back the design, and the rechargeable lithium-ion is more than half of the weight.

When you swap out brushless motors for organics, you gain and lose some things. You lose the real-time control, but you increase the runtime. You lose the noise, but you also lose the speed. You increase the range, but you probably wind up visiting the same field over and over. If your goal is to monitor the conditions of flowering crops, you may be ready to buy and install, but for the rest of us, dogs are great for carrying electronics. Oh yes. Cats are not so keen. Oh no.

The Evolution of Wireless Game Controllers

The story goes that Atari was developing a premium model of their popular home video game console, the Atari 2600, for the 1981 fiscal year. Internally known as the Stella RC, this model revision promised touch sensitive game selection toggles, LED indicators, and onboard storage for the controllers. The focus of the project, however, was the “RC” in Stella RC which stood for remote control. Atari engineers wanted to free players from the constraints of the wires that fettered them to their televisions.

Problem with the prototypes was that the RF transmitters in the controllers were powerful enough to send a signal over a 1000 ft. radius, and they interfered with a number of the remote garage door openers on the market. Not to mention that if there were another Stella RC console on the same channel in an apartment building, or simply across the street, you could be playing somebody else’s Pitfall run. The mounting tower of challenges to making a product that the FCC would stamp their approval on were too great. So Atari decided to abandon the pioneering Stella RC project. Physical proof of the first wireless game controllers would have been eliminated at that point if it were created by any other company… but prototypes mysteriously left the office in some peculiar ways.

“Atari had abandoned the project at the time…[an Atari engineer] thought it would be a great idea to give his girlfriend’s son a videogame system to play with…I can’t [comment] about the relationship itself or what happened after 1981, but that’s how this system left Atari…and why it still exists today.”

Joe Cody, Atari2600.com

Atari did eventually get around to releasing some wireless RF 2600 joysticks that the FCC would approve. A couple years after abandoning the Stella RC project they released the Atari 2600 Remote Control Joysticks at a $69.95 MSRP (roughly $180 adjusted for inflation). The gigantic price tag mixed with the video game market “dropping off the cliff” in 1983 saw few ever getting to know the bliss of wire-free video game action. It was obvious that RF game controllers were simply ahead of their time, but there had to be cheaper alternatives on the horizon.

Out of Sight, Out of Control with IR Schemes

Nintendo AVS 1985 Display
Nintendo AVS console deck and IR controller on display.

Video games were a dirty word in America in 1985. While games themselves were still happening on the microcomputer platforms, the home console business was virtually non-existent. Over in Japan, Nintendo was raking in money hand over fist selling video games on their Famicom console. They sought to replicate that success in North America by introducing a revised model of the Famicom, but it had to impress the tech journos that would be attending its reveal at the Consumer Electronics Show (CES).

The prototype system was called the Nintendo Advanced Video System (AVS). It would feature a keyboard, a cassette tape drive, and most importantly two wireless controllers. The controllers used infrared (IR) communication and the receiver was built-into the console deck itself. Each controller featured a square metallic directional pad and four action buttons that gave the impression of brushed aluminum. The advancement in video game controller technology was too good to be true though, because the entire system received a makeover before releasing as the Nintendo Entertainment System (NES) that Christmas. The NES lacked the keyboard, the tape drive, and the IR controllers and its change in materials hardly captured the high-end flash of the AVS. The removal of IR meant the device was cheaper to manufacture. A decision that ultimately helped the NES to become a breakout success that in turn brought back dedicated video game consoles single-handedly.

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