Bench Supply With Current Limiting

October 8, 2010 by Mike Szczys 14 Comments

This is a bench power supply with adjustable voltage and current limiting. [Sylvain’s] creation can regulate 0-25 volts while sourcing 0-5 amps. Current limiting is a nice feature as it will allow you to test your prototypes to ensure the power regulator you choose will not be over or underpowered.

This supply is really a two-in-one. The case has two separate circuits so that you can have different power rails going at the same time. There is a microcontroller involved, but the ATmega32 doesn’t do anything more than measure the voltage and amperage and drive the graphic LCD screen. Two potentiometers are responsible for setting the voltage and limiting the current.

[Thanks Sargonout]

Turtles All The Way Down, 40 Propeller MCU Skyscraper

October 8, 2010 by Jakob Griffith 29 Comments

Why bother interconnecting 40 Propeller microcontrollers one on top of the other? For the power that comes from parallel processing of course! [Humanoido] put the setup together for a total of 1280 ports, 640 counters, and more all running at 6.4 billion instructions per second for the low low price of 300-500$ by our count. The “skyscraper” even comes complete with software and schematics, promising developers the ability to expand or adapt for any venture. Why would we need such a setup in the first place? For any of the following: vision tracking/modification, artificial intelligence, advanced robotic control, or more.

Related: [Humanoido] loves putting MCUs together, check out one of his other creations the Basic Stamp supercomputer.

[Thanks Logan996]

Playing Piano With Optical Sensors

October 7, 2010 by Mike Szczys 16 Comments

[Sebastian] is trying to improve the responsiveness of an electric keyboard. He was unsatisfied with the lack of adequate sensitivity to keystroke. The first step in his process was to measure how fast the quickest keystroke actually is. By setting up an LED and phototransistor and taking some measurements he found that sampling at 1 kHz would be more than adequate.

With initial testing complete he ordered some CNY70 transmissive/reflective light sensors that can be place below the keys. He measures the sensor with the ADC on an ATmega16 microcontroller. Running at 16 MHz he can sample each of the eight analog-to-digital converter channels at 1202 Hz. After doing a bunch of math he put together some lookup tables that are used to translate the ADC data into midi signals. We’ve embedded a video of one sensor controlling the midi program PianoTeq. [Sebastian] also sent us a schematic of one node in the sensor network (see it after the break).

When everything is said and done he plans to use eleven ATmega16 microcontrollers to address the 88 keys, with an additional microcontroller to act as the master using a two-wire interface for communications.

Update: [Sebastian] put up a webpage with a fairly verbose description. Reading it straight from the source really clears up a lot of questions.

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An Interesting Take On WEP Cracking

October 7, 2010 by Mike Szczys 19 Comments

[Ben Kurtz] is doing a little WEP cracking but in a bit of a different way than we’re used to. WEP cracking makes us think of war driving; driving around with your laptop open, looking for WiFi access points, and stopping to run some software when you find them. [Ben’s] way is similar but different in one key way, he’s using an iPhone as the frontend.

This started as a way to find a use for some leftover equipment. He threw together a Linux box and loaded up Aircrack-ng, the software we often see used in penetration testing. To remove himself from shady-looking activities in public he coded a web interface using the Python package Turbogears. It uses screen, a program often used with SSH to run services concurrently in different terminals, with the option to disconnect without stopping the processes. Now it’s just a matter of parking the hardware near an AP, and doing the work in a browser on your mobile device. You can check out the script he wrote, as well as installation instructions, in his post linked above.

[Thanks Tech B.]

[Note: Banner image not directly related to this post]

Automated Chip Burning

October 7, 2010 by Mike Szczys 28 Comments

[Alexsoulis] needed to burn the Arduino bootloader to a slew of ATmega328 chips. Instead of sitting there and plugged the chips into a programmer one at a time, he build a robotic microcontroller programmer.

It starts with the DIP package microcontrollers in a tube, with a servo motor to dispense them one-by-one. An arm swings over and picks up the chip with a fish pump powered vacuum tweezers similar to the pick-and-place head we saw recently. From there the chip is dropped into a ZIF socket and programmed by an Arduino. Once the process is complete it is moved to the side and the process repeats.

We’ve reported on using an Arduino as an AVR programmer but we’ve never actually done it ourselves (we use an AVR Dragon programmer). Take a look at the video after the break and let us know if you think the actual programming seems incredibly slow.

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BIOS Password Cracking

October 7, 2010 by Mike Szczys 45 Comments

[Dogbert] took a look at the security that goes into BIOS passwords on many laptops. He starts off with a little background about how the systems work. People are bound to forget their passwords, so when you enter a wrong one three times in a row you get a message similar to the one above that locks you out until all power is removed from the system (then you get three more tries). But check out that five-digit number in the picture. That’s a checksum of the password. Some BIOS versions display it automatically, some require you to hold down a certain key during POST, but it’s the pivotal data needed to crack the password.

[Dogbert’s] post doesn’t go into verbose detail about the algorithms he uses to brute force the passwords. But he has posted the Python scripts he uses to do so. Learning how to generate the passwords based on the checksum is as simple as studying the code, which is often the best way to learn.

NYC Resistor Takes On The Machine

October 7, 2010 by Jakob Griffith 3 Comments

Here we are with Episodes two and three (aka, NYC Resistor part one and two) completing the Take on the Machine Hackerspace challenge we mentioned a while back. For the challenge NYC Resistor took an old style slot machine and converted it into a drink mixing deviant; even making the device post a Tweet for every drink. However, it seems to be lacking refrigeration of some kind, could this be the downfall of a potential winner for the challenge? Up next is the Hackerspace Pumping Station: One: do you think they can compete? Is there a particular Hackerspace you can’t wait to see? Let us know!

[Thanks Deven]