__ __ __ ___ / // /__ _____/ /__ ___ _ / _ \___ ___ __ / _ / _ `/ __/ '_/ / _ `/ / // / _ `/ // / /_//_/\_,_/\__/_/\_\ \_,_/ /____/\_,_/\_, / retro edition /___/Now optimized for embedded devices!!
| About | Successes | Retrocomputing guide | Email Hackaday |
Since we rely on you, our loyal readers, to supply the tasty projects that we thrive upon, we felt this writeup about how to photograph LEDs could be very useful. Photographing them can be quite difficult at times, they throw off the standard settings on your camera pretty easily. EMSL takes us through all the settings for best results. While you’re brushing up on your photography skills, you might want to consider making a flash ring, or some kind of macro lens. Now go take some awesome pictures and submit your projects.
Tired of having to physically connect to your microprocessor to upload new code? Just do it over a wireless connection. [Nathan] takes us through the process of setting up a wireless bootloader for the ATmega168. He is using the XBee base and remote modules for the wireless communication. While people have been doing wireless bootloading with the Arduino already, [Nathan] found that it was common for them to have timeout issues. His remedy was to make his own custom one that is much faster. He’s asking for help though. At this point it is tested and working, but he needs someone with more programming knowledge to help him make it “drop-in” compatible with the Arduino IDE.
Don’t forget to submit projects to our tip line.
While many of us have banished land line telephones from our houses, there are still quite a few people who utilize POTS lines today. These analog phone systems use Dual Tone Multi Frequency (DTMF) signals in order to audibly represent all of the keys on a telephone keypad and place calls. [Brad] over at LucidScience decided that it would be useful to have a DTMF decoder on hand, and got busy building one.
His DTMF decoder box uses a CM8870 DTMF decoder chip, which you might assume is all you need to get the job done. This chip performs its duties very well, outputting a 4-bit binary code for each button press it registers, but that doesn’t do a whole lot of good without being able to represent those codes in a meaningful fashion. He first built a breadboard decoder circuit that would light 1 of 16 LEDs depending on the detected button press. This was well and good, but he decided that an Arduino-driven LCD display would work far better.
When he was finished, he had a compact decoder box with an LCD display, which accepts input from either an RJ-11 cable or an audio jack. He says that the audio jack is particularly useful for decoding tones from computer audio, such as YouTube clips. [Brad] praises the CM8870 chip, stating that it can pull phone numbers from pretty much any audio or phone signal you throw at it, regardless of quality. We think it would make a great basis for a telephone-based security system, if that was something that appealed to you.
Be sure to stick around to see his DTMF decoder circuit in action.
UPDATE: Slides, paper and code
Andrea Bittau (not blurry in real life) gave a demo of the WEP fragmentation attack. The attack only requires one sniffed packet from the WEPed network unlike replay attacks which usually require you to get an ARP packet. He built a simple tool to sniff a packet and then build packets to create a legitimate connection to the access point. At this point a server on the internet is contacted to flood the network with packets at up to 1400 packets per second. This generates a ton of unique IVs and aircrack is called every 100000 packets till the WEP key is cracked. In the demo it took under 5 minutes for the automated process to complete.
[Stephen Eaton] created an enclosure and shared his process in a pair of blog post. We thought is was amusing that he remarks on how rarely his projects get the to point that you’d want to make an enclosure for them. We’ve certainly got a lot of bare-PCB creations lying around. But when it does come time, we think his fabrication method is a good way to go.
First of all, he didn’t start from scratch. He already had a SparkFun project case sitting around. The problem is figuring how to make it work for your situation. We’ve used a drill, a Dremel, and a file in the past and that yields passable results but nothing that would be mistaken for anything other than a carefully mangled project box. [Stephen] decided to mill the openings he needed from the box, which yielded professional looking results. He started by emailing SparkFun and asking if they could give him a 3D model of the project box and the obliged. He then modeled the LCD screen, LED light pipes, button, USB port, and SD socket. From there it was off to the mill with a custom jig and a few tricks we think you’ll appreciate. The end result is just another reason to build the CNC mill you’ve had on your mind for so long.