Wireless Power Transfer Using Capacitive Plates

July 17, 2015 by James Hobson 33 Comments

It seems like wireless power transfer is all the rage these days. There’s wireless charging mats, special battery packs, heck, even some phones have it built in! And they all use inductive coils to transfer the power — but what if there was another way? Coils of copper wire aren’t always that easy to fit inside of a product…

As an experiment, [Josh Levine] decided to try making a proof of concept for capacitive power transfer.

He first demonstrates inductive power transfer using two coils of copper wire to power up an LED. The charging coil is supplied with 15V peak-to-peak at 1MHz which is a fairly typical value for inductive charging. He then shows us two glass plates with some tinfoil taped to it. Two LEDs bridge the gap alternating polarity — since the power is oscillating, so we need a path for electrons to flow in both directions. There is no connection through the glass, but when it is set on the charging plate, the LEDs light up. The charging plate is supplied with 30V peak-to-peak at 5MHz.

Continue reading “Wireless Power Transfer Using Capacitive Plates” →

Hacklet 56 – Brain Hacks

July 17, 2015 by Adam Fabio 7 Comments

The brain is the most powerful – and least understood computer known to man. For these very reasons, working with the mind has long been an attraction for hackers, makers, and engineers. Everything from EEG to magnetic stimulus to actual implants have found their way into projects. This week’s Hacklet is about some of the best brain hacks on Hackaday.io!

[Paul Stoffregen], father of the Teensy, is hard at work on Biopotential Signal Library, his entry in the 2015 Hackaday Prize. [Paul] isn’t just hacking his own mind, he’s creating a library and reference design using the Teensy 3.1. This library will allow anyone to read electroencephalogram (EEG) signals without having to worry about line noise filtering, signal processing, and all the other details that make recording EEG signals hard. [Paul] is making this happen by having the Teensy’s cortex M4 processor perform interrupt driven acquisition and filtering in the background. This leaves the user’s Arduino sketch free to actually work with the data, rather than acquiring it. The initial hardware design will collect data from TI ADS129x chips, which are 24 bit ADCs with 4 or 8 simultaneous channels. [Paul] plans to add more chips to the library in the future.

Next up is [Jae Choi] with Lucid Dream Communication Link. [Jae] hopes to create a link between the dream world and the real world. To do this, they are utilizing BioEXG, a device [Jae] designed to collect several types of biological signals. Data enters the system through several active probes. These probes use common pogo pins to make contact with the wearer’s skin. [Jae] says the active probes were able to read EEG signals even through their thick hair! Communication between dreams and the real world will be accomplished with eye movements. We haven’t heard from [Jae] in awhile – so we hope they aren’t caught in limbo!

[Qquuiinn] is working from a different angle to build bioloop, their entry in the 2015 Hackaday Prize. Rather than using EEG signals, [Qquuiinn] is going with Galvanic Skin Response (GSR). GSR is easy to measure compared to EEG signals. [Qquuiinn] is using an Arduino Pro Mini to perform all their signal acquisition and processing. This biofeedback signal has been used for decades by devices like polygraph “lie detector” machines. GSR values change as the sweat glands become active. It provides a window into a person’s psychological or physiological stress levels. [Qquuiinn] hopes bioloop will be useful both to individuals and to mental health professionals.

Finally we have [Marcin Byczuk] with Biomonitor. Biomonitor can read both EEG and electrocardiogram (EKG) signals. Unlike the other projects on today’s Hacklet, Biomonitor is wireless. It uses a Bluetooth radio to transmit data to a nearby PC or smartphone. The main processor in Biomonitor is an 8 bit ATmega8L. Since the 8L isn’t up to a lot of signal processing, [Marcin] does much of his filtering the old fashioned way – in hardware. Carefully designed op-amp based active filters provide more than enough performance when measuring these types of signals. Biomonitor has already found it’s way into academia, being used in both the PalCom project, and brain-computer interface research.

If you want more brain hacking goodness, check out our brain hacking project list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Send In The Drones: Putting Wheels And Wings On The Internet Of Things

July 17, 2015 by Dan Maloney 17 Comments

Imagine you’re a farmer trying to grow a crop under drought conditions. Up-to-the-minute data on soil moisture can help you to decide where and when to irrigate, which directly affects your crop yield and your bottom line. More sensors would mean more data and a better spatial picture of conditions, but the cost of wired soil sensors would be crippling. Wireless sensors that tap into GSM or some sort of mesh network would be better, but each sensor would still need power, and maintenance costs would quickly mount. But what if you could deploy a vast number of cheap RFID-linked sensors in your fields? And what if an autonomous vehicle could be tasked with the job of polling the sensors and reporting the data? That’s one scenario imagined in a recent scholarly paper about a mobile Internet of Things (PDF link).

In the paper, authors [Jennifer Wang], [Erik Schluntz], [Brian Otis], and [Travis Deyle] put a commercially available quadcopter and RC car to the hack. Both platforms were fitted with telemetry radios, GPS, and an off-the-shelf RFID tag reader and antenna. For their sensor array, they selected passive UHF RFID tags coupled to a number of different sensors, including a resistance sensor used to measure soil moisture. A ground-control system was developed that allowed both the quad and the car to maneuver to waypoints under GPS guidance to poll sensors and report back.

Beyond agriculture, the possibilities for an IoT based on cheap sensors and autonomous vehicles to poll them are limitless. The authors rightly point out the challenges of building out a commercial system based on these principles, but by starting with COTS components and striving to keep installed costs to a minimum, we think they’ve done a great proof of concept here.

Fooling Google Search Console With Tricky PHP

July 17, 2015 by Rick Osgood 42 Comments

When [Steve] received a notice from Google that a new owner had been added to his Google Search Console account, he knew something was wrong. He hadn’t added anyone to his account. At first he thought it might be a clever phishing tactic. Maybe the email was trying to get him to click a malicious link. Upon further investigation, he discovered that it was legitimate. Some strange email address had been added to his account. How did this happen?

When you want to add a website to Google’s services, they require that you prove that you own the actual website as a security precaution. One method to provide proof is by uploading or creating an HTML file to your website with some specific text inside. In this case, the file needed to be called “google1a74e5bf969ded17.html” and it needed to contain the string “google-site-verification: googlea174e5bf969ded17.html”.

[Steve] logged into his web server and looked in the website directory but he couldn’t find the verification file. Out of curiosity, he tried visiting the web page anyways and was surprised to find that it worked. After some experimentation, [Steve] learned that if he tried to load any web page that looked like “googleNNNNNNN.html”, he would be presented with the corresponding verification code of “google-site-verification: googleNNNNNNNN.html”. Something was automatically generating these pages.

After further investigation, [Steve] found that some malicious PHP code had been added to his website’s index.php page. Unfortunately the code was obfuscated, so he couldn’t determine exactly what was happening. After removing the new code from the index.php file, [Steve] was able to remove the hacker’s email address from [Steve’s] Google account.

This is a very interesting hack, because not only did it allow this one hacker to add himself to [Steve’s] Google account, but it would also have allowed anyone else to do the same thing. This is because each new hacker would have been able to fool Google’s servers into thinking that they had uploaded the verification file thanks to the malicious PHP code. It makes us think that perhaps Google’s verification system should use a separate randomized string inside of the verification file. Perhaps one that can’t be guessed or calculated based on known variables such as the file name.

Transmitting MIDI Signals With XBEE

July 17, 2015 by Rick Osgood 27 Comments

What do you do when you want to rock out on your keytar without the constraints of cables and wires? You make your own wireless keytar of course! In order to get the job done, [kr1st0f] built a logic translator circuit. This allows him to transmit MIDI signals directly from a MIDI keyboard to a remote system using XBEE.

[kr1st0f] started with a MIDI keyboard that had the old style MIDI interface with a 5 pin DIN connector. Many new keyboards only have a USB interface, and that would have complicated things. The main circuit uses an optoisolator and a logic converter to get the job done. The MIDI signals are converted from the standard 5V logic to 3.3V in order to work with the XBEE.

The XBEE itself also needed to be configured in order for this circuit to work properly. MIDI signals operate at a rate of 31,250 bits per second. The XBEE, on the other hand, works by default at 9,600 bps. [kr1st0f] first had to reconfigure the XBEE to run at the MIDI bit rate. He did this by connecting to the XBEE over a Serial interface and using a series of AT commands. He also had to configure proper ID numbers into the XBEE modules. When all is said and done, his new transmitter circuit can transmit the MIDI signals wirelessly to a receiver circuit which is hooked up to a computer.

Hackaday Prize Entry: New Firmware For A Smartwatch

July 16, 2015 by Brian Benchoff 25 Comments

Smartwatches are the next big thing. Nobody knows what we’re going to use them for, but that’s never stopped a product from being the hottest item around. The WeLoop Tommy isn’t the Apple Watch, it isn’t the Moto360, and it isn’t the Microsoft Band. It is, however, a nice smartwatch with a Sharp memory display and a battery that lasts longer than a few days. For his Hackaday Prize entry, [Krzysiek] is making an open source firmware for the WeLoop Tommy that will add capabilities no other smartwatch has.

This project is a complete reverse engineering of the WeLoop Tommy smartwatch. [Krzysiek] is tearing everything down to the bare components and figuring out how the RAM, Flash, buttons, LCD, and accelerometer connect to the processor. After that, it’s time for custom firmware.

Already [Krzysiek] has a test app that displays [OSSW] on the Sharp memory display. It’s not much, but the hardware is solid. With the right firmware, the WeLoop Tommy will be able to do just about everything an Android, Apple, or Microsoft smartwatche can do using repurposed hardware and open source firmware.

The 2015 Hackaday Prize is sponsored by:

29 Year Old Apple Computer Finally Gets An OS Update

July 16, 2015 by Kevin Dady 36 Comments

The Apple IIGS is the 16 bit upgrade to the popular 8 bit Apple II computer line, and with its massive boost in graphics, an Ensoniq sound system, and backwards compatibility with the 8 bit machines makes this box desirable to many retro enthusiast. The last OS update, 6.0.1, was released over 22 years ago. While it worked well for the early 90s, it was by no means perfect.

Last Sunday, a post popped up on callapple.org, announcing Apple IIgs System 6.0.2. Updates include a driver for the unreleased Apple II Ethernet card, fixes various bugs in the file system translation system, various bugfixes to existing system programs, fast drawing and animation tools, and of course an update to the finder to show the new revision number.

With a hope for even more bug fixes in a possible 6.0.3 revision its good to see people still giving the old Apple II line some love, as the old Apples don’t have as large of a following as their Atari and Commodore brethren.