TechCrunch Disrupt: Charging A Phone With Its Own Transmitter

May 5, 2015 by Brian Benchoff 109 Comments

TechCrunch Disrupt is on this week, and that means we get to see which members of tech media don’t understand basic physics. So far, it’s writers from Engadget, The Mirror, Business Insider, TechCrunch, and four judges on the TC Disrupt stage. What is the consequence of not understanding the implications of the conservation of energy? Glowing support for a cell phone that can charge itself.

The offending Disrupt startup is Nikola Labs, and they’re gearing up to launch a Kickstarter for a very special iPhone 6 case. This case uses small, energy-harvesting antennas to gather RF energy from the cellphone tucked away in this case. This energy is then sent to a rectifier where it is converted into something the Apple Lightning connector can sip power from. According to Nikola Labs, this RF harvesting antenna takes energy from the transmissions of the iPhone 6 entombed in this case, converts it to about 5 Volts, and uses that to charge the iPhone battery.

I know that seems difficult to understand, so here’s a simple analogy: you have a flashlight with a battery and a solar cell. The solar cell recharges the battery. If this were a Nikola Labs flashlight, you would recharge it by shining the flashlight onto the solar cell.

That is the simplest explanation of what the Nikola Labs cellphone case does, and illuminates the limitations of what it can do. If the ‘energy harvesting circuit’ collects power from the device it is recharging, it will reduce the transmission power of whatever is transmitting. With the cellphone case, you’re spending transmission power (plus efficiency losses) to recharge the battery. That means poorer reception and fewer bars. In the solar-recharging flashlight analogy, the flashlight would either be dimmer, or you could only use it part of the time.

It’s also why Nikola Labs claims their case will only recover 30% of the battery life of an iPhone 6; the battery isn’t solely dedicated to a transmitter – there’s a display and a CPU to account for in the power budget.

To Nikola Labs’ credit, this is at least a novel application of the RF energy harvesting trope that has been making its way around Kickstarter and tech blogs for a few years. Nearly every other RF harvesting idea that has been pitched in recent memory decouples the transmitter (or ‘generator’, I guess) with the product or receiver. The square cube law is an evil mistress, and if you’re wondering why these devices don’t work, [ch00f], a guy with an actual engineering degree, has a great writeup of one of these products over on Drop Kicker.

The Nikola Labs cellphone case bucks this trend by looking at the shortcomings of these devices; an RF rechargeable Bluetooth tag won’t work if you place it a foot away from a WiFi router, but it just might if you tape it to the antenna. This is the idea behind Nikola Labs’ invention: harvest energy from a few millimeters away from the cell phone’s antenna. According to Nikola Labs, their engineer, [Chi-Chih Chen] has a patent in the works for this. This patent application has not been published yet.

In theory, the Nikola Labs cellphone case will actually recharge your battery, but at a price: you’d be wasting your transmission power on recharging the battery. It’s a false economy that you’ll be able to fund on Kickstarter next month for $100 USD. If you’re only looking for more battery life, walk into any gas station, buy a $10 USB power bank/battery, and have enough portable power to recharge your iPhone battery to 100%. That’s not a sexy solution, it doesn’t reference [Nikola Tesla], and it’s not snake oil that tech media is lapping up like dogs. Pity.

1337-sp34k Keyboard

April 14, 2015 by Anool Mahidharia 13 Comments

What started off as a quick prank-hack to re-map a colleague’s keyboard turned into a deep dive in understanding how keyboards work. [ch00f] and his other work place colleagues are in a habit of pulling pranks on each other. When [ch00f]’s buddy, who is an avid gamer and montage parody 1337-sp34k (leet speak) fan, went off on a holiday, [ch00f] set about re-mapping his friend’s keyboard to make it spit out words his friend uses a lot – “SWAG” “YOLO” and “420”. But remapping in software is too simple, his hack is a hardware remapping!

The keyboard in question used mechanical keys mounted on a keyboard sized PCB. Further, it was single sided, with jumper links used in place of front side tracks. This made hacking easier. The plan was to use keys not commonly used – Scroll Lock, Print Screen, and Pause/Break – and get them to print out the words instead. The signal tracks from these three keys were cut away and replaced with outputs from a microcontroller. The original connections were also routed to the microcontroller, and a toggle switch used to select between the remapped and original versions. This was eventually not implemented due to a lack of space to install the toggle switch. [ch00f] decided to just replace the keyboard if his friend complained about the hack. A bit of work on the ATMega PCB and firmware, and he was able to get the selected keys to type out SWAG, YOLO and 420.

And this is where a whole can of worms opened up. [ch00f] delves in to an explanation on the various issues at hand – keyboard scanning/multiplexing, how body-diodes in switching FET’s affected the scanning, ghosting and the use of blocking diodes. Towards the end, he just had the word SWAG activated by pressing the Pause/Break key. But he does get to the bottom of why the keyboard was behaving odd after he had wired in his hack, which makes for some interesting reading. Don’t miss the video of the hack in action after the break.

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Towards More Interesting Instant Cameras

December 18, 2014 by Brian Benchoff 22 Comments

When [Ch00f] was getting jeans rung up at Nordstroms, he noticed how fast thermal receipt printers can put an image on a piece of paper. This observation isn’t unique to the circles [Ch00f] frequents – there are a few small receipt paper printers out there that connect to the Internet, iPhones, and a whole bunch of other Kickstarter-friendly keyword devices.

Nevertheless, a device that can make a hard copy of an image quickly and cheaply isn’t something you just stop thinking about. After rolling the concept around in his head for a few years, [Ch00f] finally came up with the perfect build – a camera.

The hardware for the build is based around an STM32F4 Discovery board. It’s a bit overpowered for this sort of application, and this is one of [Ch00f]’s first adventures in ARM-land. The rest of the hardware consists of a thermal receipt printer and a JPEG camera, the latter of which replaced a cellphone CMOS camera module that was lost in a move.

A custom camera requires a custom enclosure, and for this [Ch00f] made something remarkable. The entire enclosure is CNC milled out of a beautiful piece of figured walnut. The end result looks far too good for a prototype, but it does polish up nicely with a bit of linseed oil.

Now [Ch00f] has an instant camera that takes the idea of a Polaroid and turns it into something that produces a print for tenths of a cent. There’s a time-lapse function – just a zip tie on the shutter button – filters with the help of highlighters, and the ability to record movies in flipbook format.

It’s a great project, and also something that will make for a great crowdfunding campaign. [Ch00f] has already started work on this. He already has a sleek, modern-looking website that requires far too much scrolling than should be necessary – the first step to a winning Kickstarter. [Ch00f] also learned a lot about ARMs, DMA, dithering, gamma correction, and the JPEG format, but that’s not going to get anyone to open up their wallet. You know what will? A slick video. You’ll find that below.

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Hackaday Links: October 19, 2014

October 19, 2014 by Brian Benchoff 26 Comments

Introducing the Hayes Smartmodem 1200. The era of the single station microcomputer…. is over. The Hayes Smartmodem offers advanced features like auto answer and auto dial. Now if we could only find an ‘RS-232 Computer.’

Have a 3D printer and an old router? How about controlling your printer with Octoprint? For some cases, it might be better than using a Raspberry Pi and OctoPi, but you won’t get a camera for streaming pics of your builds to the web.

Last year, [CNLohr] built a microscope slide Minecraft thing and in the process created the smallest Minecraft server ever. The record has now been bested with the Intel Edison. There’s a bit of work to install Java, but the performance is pretty good for one player. Bonus: Minecraft is a single threaded app, so you have another core for garbage collection.

Remember the Scribble pen, that showed just how gullible people are and how crappy tech journalism is? They’re back with a beta program. A mere $15 guarantees you a scribble pen for their beta program. I wouldn’t give these guys $15 of someone else’s money, but lucky for us [ch00f] bit the bullet. He’ll be updating everyone on the status of his fifteen dollars, I’m sure.

Hey, guess what will eventually be in the Hackaday store? Keycaps for your mechanical keyboard. Yes, we actually figured out a way to do this that makes sense and won’t lose money. Pick your favorite, or suggest new ones in the comments:

BSAPEDWLOVKTUB.YBKAB

Scribble And The Failings Of Tech Journalism

September 4, 2014 by Brian Benchoff 79 Comments

The Scribble Pen, you may remember, is a project by bay area startup Scribble Technology that puts a color sensor and multiple ink reservoirs in a pen. We’ve talked about it before, right after they cancelled their Kickstarter campaign after netting 366% of their original goal.

Yes, they cancelled their campaign after being successfully funded. To Kickstarter’s credit, the Scribble team was asked to provide a better video of the pen demonstrating its capabilities. The team pulled the plug on the campaign, saying they’ll be back soon.

Here is the new campaign. The attentive reader will notice the new campaign is not a Kickstarter project; instead, it is a Tilt campaign. What is Tilt? It’s a platform that allows for crowdfunding, fundraising, pooling, and other ‘many wallets into one’ Internet-based projects. It’s actually not a bad idea if you’re raising funds for a charity or the Jamaican bobsled team. For crowdfunded product development, caveat emptor doesn’t quite cover it.

With more than $200,000 in the bank, you would think the questions asked in many comments on the old Kickstarter would be answered. They were. Scribble put up a new video showing the pen drawing different colors of ink on a piece of paper. This video was faked. [Ch00f] at Drop Kicker took apart the new video frame by frame and found these – ahem – scribbles were inserted in post production. The video has since been replaced on the Tilt campaign page, but evidence of Scribble deleting comments questioning this exists.

Any idea of the Scribble pen being real has been put to bed. Kickstarter threatened to remove the campaign if a better video could not be produced within 24 hours. The Scribble team cancelled their campaign to regroup and put together a better video. In two weeks, the team was only able to produce a faked video. The Scribble pen does not exist.

Case closed, you might think. Digging into videos frame by frame will tell you a lot, but it won’t give you the full picture. We know what happened with the Scribble pen, but very little about the who, why, and how this huge, glaringly obvious fraud occurred. Before we get to that, hold on to your hats – it only gets shadier from here on out.

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Gutenberg Clock Keeps Time By Reading Books

August 13, 2014 by Eric Evenchick 16 Comments

We’ve seen a wide variety of hacks that keep time, but [ch00f]’s latest build takes a new spin on counting the seconds. The Gutenberg Clock keeps time by reading books on a scrolling LED screen.

The content for the clock is sourced from the Project Gutenberg, which releases books with expired copyright for free. The library on the clock consists of around twenty thousand such books. Read at eighty words per minute, the clock won’t repeat a passage for the next thirty-three years.

While the clock doesn’t display time itself, it is synchronized to time. Two identical clocks should display the same text at the same time. To get the time, [ch00f] first tried hacking apart a cheap radio clock, which is synchronized to NIST’s 60 kHz broadcast. After reverse engineering the protocol with great success, stray RF energy from the display turned out to cause too much interference.

With the cheap solution out the window, [ch00f] built a custom breakout for an Adafruit GPS module and used it to get the time. This was his first RF board, but it worked out fine.

Books are loaded onto a FAT filesystem on an SD card, and [ChaN]’s FatFS is used to interpret the filesystem. A microcontroller then sends the text out at a constant rate to a serial port on the display which he hacked his way into.

The project is a neat mix of art and electronics. Stick around for a video overview after the break.

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Reverse Engineering HitClips

January 1, 2014 by Brian Benchoff 31 Comments

hitclipz

After a quick review of the Hackaday viewer demographics, we need to say the late 90s were weird. Even portable audio players were downright bizarre: MP3 players existed, but you loaded up your songs (all eight of them) over your PC’s parallel port. While helping a cousin move some furniture, [Ch00f] found a huge collection of one of the oddest music formats ever: HitClips, a tiny plastic encapsulated bit of circuitry that stores 60 seconds of terrible-sounding mono audio. Yes, this was a thing, but so was the pet rock. With no HitClips player, [Ch00f] decided he would take a swing at reverse engineering these tiny, tinny songs.

After taking apart the plastic enclosure, [Ch00f] found a very simple circuit: a few resistors, a cap, and an epoxy blob that enclosed an die with the musical data. On the back of the clip, there are eight pads for connecting to the player. With nothing to go on, [Ch00f] started poking around and found connecting one of these pins to ground caused circuit to draw 300uA of current for about 60 seconds – the same length of time as the recorded sample.

[Ch00f] originally thought the HitClip would provide audio data over an SPI or other digital protocol. What he found was much more interesting: two of the pins on the HitClip correspond to the push and pull FETs of a class D amplifier. The audio on the HitClip is digital audio, but it’s encoded so it can directly drive an analog circuit. Pretty clever engineering for a happy meal toy, if you ask us.

After dumping this data with a logic analyzer, [Ch00f] turned all the values in to .WAV file. It was, amazingly, music. A little refinement to the process to nail down the timing resulted in a 60-second clip seen (heard?) after the break.

Since [Ch00f] doesn’t want to spend $40 on eBay for a vintage HitClips player, he’s right about at the limit of what he can reverse engineer out of these cheap, crappy music chips. He has put up all his documentation, though, so if you’re up for improving on [Ch00f]’s methods, have a go.

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