[Andy] sent in this pdf (mirror) describing a simply diy UWB Radar project. It’s not intuitive, but by using a wide frequency range for low power, short distance purposes, the system should avoid interfering with other radio systems. The paper has a complete circuit schematic, and offers some suggestions for adding communications to the signal. Unfortunately, to really tune the thing, you’ll need a kick-ass oscilloscope.
Misc Hacks4186 Articles
Speaker As A Microphone
[Nathan] sent in his speaker microphone project. Speakers and microphones are physically similar – usually mics are much smaller to allow decent high frequency response. In this case, [Nathan] wanted something to pick up kick drums or bass guitars, without the cost of a commercial version like the subkick. It’s built around a dual coil 6.5 inch subwoofer. The passive circuit design allows the coils in the speaker to be configured for differing impedance, phase and isolation.
Stroboscope LED Fan Clock
[sprite_tm] sent in one of his latest little adventures – and I love it. To create his stroboscope fan clock, he put a couple of red and green clock hands onto a standard PC fan(I love Panaflo fans), then he built a circuit to strobe a RGB LED to create a set of virtual clock hands on the spinning fan. An ATTiny2313 does all the work, with the help of some transistors to drive the LEDs.
ToorCon 9: URI Use And Abuse
[Nathan McFeters] and [Rob Carter] gave a presentation on the problems with URI handling. URIs are used to send commands to external applications from a web browser. itms:// for iTunes for example. Any application that registers a URI has the potential to be abused through this route. For their first example they showed a stack overflow in Trillian’s AIM handling. The next demo created a “Critical Update Available” button on Picasa’s interface. When the user clicked it, their photos would be uploaded to the attacker’s server. They even display a “download progress” bar to encourage the user to keep the connection open. You can read about the attack on cocontributor Billy Rios’s blog.
ToorCon 9: CDMA Unlocking And Modification
[Alexander Lash] gave a short overview of what you need to unlock a CDMA phone. He strongly recommended Howard Forums for finding most of the info you need. You’ll probably need BitPim and the Qualcomm PST (product support tools). Using the PST you can flash your new carrier’s firmware and then activate the phone on their network.
Verizon offers two ways to get unlimited EVDO data. $59 for a data plan or $15 for VCast. You’re not supposed to be able to use your VCast phone as an EVDO modem and it sends a different network access identifier (NAI) if you tether the phone. Using the PST you can change the NAI and use the cheaper VCast plan for data access. Here is a forum post detailing the process.
Drive Bay PoE Adapter
Sure, we’ve seen Power over Ethernet before – I even whipped up a simple adapter for my modded wrt54gs. This is a nice clean setup, and it’ll save you from yet another power brick. (I’ve got a power strip dedicated to the things in my tiny home data center.)
Optical Headphone Amp
It looks like this one’s been out there for a while, but it doesn’t make it any less awesome. [Andrija] built this combination portable DAC/headphone amp. It takes optical audio input, feeds it through an analog devices AD1866 16bit/96khz decoder. After that, the audio is brought up to volume by an op-amp style headphone amp circuit.
Side note: I wrote up a few short notes on the Sidekick LX I got today, if you dig that sort of thing.
