If you're serious about your headphone amps, you probably already know about the M3 headphone amplifier. Instead of going for the extra tiny, they're going the 'screw the size, it's all about the sound' route. Thsi thing needs a 24v .5amp power supply. Boards are available, and the discussion has gotten so long on headwize that they exceeded the maximum thread length.
I got busy with the laser last night and came up with something new: a custom etched track pad. It still works, with a bit of added texture where I introduced it to the warm glow of the laser. Hit the link for pics and a walk through.
After months of waiting, emailing and waiting some more, I took the afternoon off to stay home and wait for this special delivery. (I had to wait an extra day due to a shipping issue!) I received three huge boxes in my workshop. Not only did I receive this (not so mini) Epilog mini 24, I put together a stand and unpacked a monster air filter.
Read on for the obligatory Hack-A-Day logo and my first impressions of this sweet piece of kit.
Writing with a laser pointer has been done, but [Chris]'s roll your own version feeds the data the display pc using VNC. He's got some speed issues, but I'm giving him points for most original use for remote desktop software.
[FX] from Phenoelit gave an entertaining talk about barcode security. He covered both how the systems are implemented and how they've been exploited. The first example was a parking garage in Dresden that issues non unique barcodes for the unlimited passes that hotels give out. Anyone code print out an image of that particular code and park for free. German grocery stores have automated machines that refund you for your empty beer bottles. The barcode generated just states the refund amount (5 digits) that you'll get at the register. Just stick the barcode under something like a six pack and it'll scan even without the cashier seeing it.
Check out the video to find out more silliness involving DVD rentals, boarding passes, asset management, and SQL injection via the scanner. You can even find higher res versions in the 24C3 media archives.
[bodiby] was first to send in this New Scientist article about converting a DVD drive into a lab scanner. I did some digging and came up with the details. Here's the paper describing the process and results. Here's a basic schematic and description of the mod. A set of samples is placed onto a CDR. A photo sensor is used to locate the samples on the CD, while the laser is fired through each sample. A planar photodiode is used to measure the attenuation of the laser as it's transmitted through each sample. Sadly, I couldn't find any details on the custom control electronics.
[John] sent in this cell phone activated rifle scope laser security camera blinder. The phone plays a tone when it receives a SMS message. The sound activates an audio controlled relay. (Not elegant, but it works) which powers a laser that's been mounted to a rifle scope. The scope is used to align the laser with the target lens - on activation it's supposed to blind the camera. Looks like a fun hack, even if the uses are a bit nefarious. (He left out a little detail that'll make or break the project to keep things on the level, but it's not that hard to figure out.)
[Mike] wanted a better power supply for his argon laser, so he modded some switchmode power supplies. With a few tweaks, he had a few adjustable voltage outputs and a nice solid supply of electrons for his laser projects. If you need a lab quality adjustable power supply for your projects, this is a nice way to get it on the cheap. (He's in the UK, but the same ideas should apply to us models.
I found this on [hackedgadgets] and checked out the paper describing the project. I'm not sure if it will generate any truly usable graphics any time soon, but the technology is pretty interesting. It combines six video channels and uses acoustic frequencies and tiny but simple looking transducers to vibrate the crystal that channels a laser to generate the hologram. (If I read that paper correctly) Surprisingly, a single nvidia chip generates all six channels for the system. Annoyingly, there's a lack of info on MITs site, but there's a nice group of images under the multimedia link of this article.
This hack was linked a bit back in February, but it just didn't get a decent write up. They used this 5000 lumen projector, a zoom lens video camera and a 60mw green laser pointer to generate interactive graffiti on nearby buildings. Most of the link love focused on the show-off video. I'm surprised that nobody mentioned the most obvious use: a laser pointer reactive white board. I could have loads of fun with this and my laptop during presentations. Thanks to [Brishen] for reminding me of this one.
I signed the papers on my first house today! In celebration, I started looking for some home hardware hacks, but stumbled across this old (2003) laser power meter sensor. If you like to scare off the power guys, this is the way to go. [jake] used a laser pointer, probably a PIC and some sort of photo sensor to count the revolutions of his meter.
I found [Stefan]'s work through his older, but interesting TinyProjector project. He opted to use multiple diodes in various configurations with rotating mirrors to create images. He's built quite a few interesting projects over the years. The WeatherTank is pretty sweet.
The laser community forums have a nice primer on basic laser effects. [Steve] thought I'd really be interested in this sweet prototype dual laser saber. It's a custom piece that uses a wicked laser pointer (You can use any laser, but those happen to be damn powerful) and a polycarbonate blade(tube/rod) to create the hallowed light saber effect. (Now I know what I want for christmas.) Mcmaster-carr carries polycarbonate rod and tube if you want to make your own,
It's that time of year when [Bruce Land] sends in the latest batch of Cornell mcu final projects. There are 32 new projects this year - including a model retina built from RGB LEDs and photo sensors. My favorite has to be laser pong. Or maybe the wearable air guitar. Damn, I can't make up my mind.
This has been around for a while, but I thought it deserved some attention. [Todd] used a laser pointer, a webcam, some trig and (sigh) some windows development tools to create his own laser range finder. Given the position of the beam strike and that the camera is located at a right angle to the laser, calculating the distance is pretty simple. This could be handy if you're building a bot for defcon...
[Mr Beam] sent this in yesterday, but I didn't have a chance to get it up til now. These guys are using a 2Kw laser to heat up their instant coffee and tea. Sure, it's not a hack, but [Eliot] wanted it up, and who doesn't want their own 2Kw Laser?
