Gesture control uses WiFi doppler shift


We’ve said it before: in the future simple interfaces will use nothing but your body. At least at first glance that’s the case with this WiFi-based gesture control system. If you have Internet at home you probably have a WiFi access point. That’s the first portion of the equation. The remainder is a way of measuring how the radio waves bounce off of your body. So far this is being done with Software-Define Radio (SDR) but researchers at University of Washington think it may be possible to build the technique into future WiFi devices.

The demo video shows this man waving his arm to adjust the volume of his home entertainment system. Intuition tells us that this would be impossible if your arm wasn’t the only thing in motion at the time. But that issue is quickly addressed. Multiple antennas can track multiple people at the same time. There is also consideration for false-positives. The system requires a moderately complex wake-up gesture sequence to prevent you from, say, accidentally turning on the stereo when you roll over in bed.

If you’re having trouble wraping your mind around this, consider this ultrasonic music player. The WiFi version does the same thing, but processing changes in the returning radio waves is much more complex.

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LED mortar board battles suns brightness with 21W of power


[Jeremy Blum] aimed to be the brightest student at his Master’s graduation ceremony this spring. He designed an LED rig for his mortar board which should battle the sun’s intensity by using up to 21 watts of power. But he didn’t stop with eye-catching intensity. while he was at it he also included some interactive features so the guy behind him has a way to keep from going blind.

One thing that really caught our eye is the 3D printed parts he generated for the project. There’s a nice mounting plate for the LED side of things, and a wrist-mounted enclosure for the Raspberry Pi board. Wait, why does he need an RPi to drive some LEDs? We already mention interactivity which is facilitated by the Pi acting as a WiFi hotspot. Connect to the access point and choose a color. If you’re in the seat behind [Jeremy] you’ll want to choose black! All of this and is explained in his video presentation.

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WeMo without a smartphone


[Matt Galisa] decided to try his hand at setting up the Belkin WeMo outlet without using a Smartphone app. The hardware is a pass-through for mains voltage which allows you to switch the plug over the network. It has a built-in WiFi module which normally connects to your home network. But the first time that you power it up it announces its own SSID designed for an iOS (and recently Android Beta) app to connect to in order to enter your AP credentials.

He started with this Python script used for WeMo hacking. It was originally meant to issue commands to the outlet once it had passed the initial setup. [Matt] followed along but couldn’t get an answer on the port he expected. It turns out that the device listens on a different port until the initial setup is complete (probably so that you don’t mess up other outlets on the network that are already working correctly). His next challenge was to manually set the WPA credentials. This never really worked and he ended up using a virtual AP without password protection through DD-WRT. From there he was able to set up a Python script to turn on, off, and toggle the state of the outlet.

If you’re looking to dig deeper into the device’s security check out this project.

Solar powered WiFi repeater

For all those times you need to broadcast your own access point where there’s no outlet [Larry] shows us how to make a solar-powered hotspot. He started by slapping a solar panel on the lid of a cigar box and attaching it to five rechargeable AA batteries inside. These power the mainboard from a router which is the perfect size to friction fit in the opening. It has been flashed with a copy of DD-WRT, and set to scan for open WiFi connections. When it finds one it connects and rebroadcasts its own WiFi signal to the surrounding area. He leaves it in the back window of his car and uses it to get on the net during lunch.

PDF redaction still not working


Facebook’s internal valuation was revealed this week thanks to shoddy PDF redaction. Court documents from a settlement between Facebook and ConnectU showed that Facebook values itself at $3.7 billion, much less than the $15 billion that was speculated during the Microsoft investment. The AP uncovered this by cutting and pasting from the redacted court document. It’s the same thing we showed in our PDF redaction screencast last summer… and it will never cease to be funny.

[photo: Bryan Veloso]

WiFi theremin

The fine folks at Midnight Research Labs have put together a new toy for you to play with. It’s a Python script that makes your WiFi hardware behave more like a theremin. Based on the pyaudio library it monitors the signal strength of the AP you’re connected to and changes the tone accordingly. There’s a sample embedded above (direct link). If you have a second interface, you can use it to modulate the volume. It’s an interesting trick, but they say that there’s enough latency that it would be hard to play actual music with it.