Retro Adapter For Canon SLR

November 20, 2010 by Chris Nelson 19 Comments

[calculon] was able to modify a “dumb” adapter to allow his Canon SLR to use the aperture and focus on a retro lens. With his new flip mounted wide angle lens he was able to achieve some pretty neat macro shots. By cutting away some of the cheaper ring he was able to feed the wire through and glue it onto the the cameras contact points. The wire was then attached to the inputs on the “new” lens. With a new adapter running about $375 not only was this a neat little hack but it was also a money saver. You can see some more of his photos on his flicker

Beginner Concepts: Powering Your Projects

November 20, 2010 by Chris Nelson 44 Comments

Powering your gadgets generally seems like a necessary evil. To help with this [Felipe La Rotta] made a really nice bench power supply using a PC power supply and a LM317 adjustable voltage regulator. PC power supplies are an example of a switched power supply(more on that later). The LM317 is a type of linear voltage regulator that allows for adjusting the output voltage by varying some resistors. Whats the best way to power your circuits? well that depends…

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Electromechanical Computer Built From Relays

November 18, 2010 by Mike Szczys 41 Comments

This is Zusie, a computer built out of electromechanical relays. [Fredrik Andersson] picked up a lot of about 100 telephone exchange circuit boards, each with about 16 relays on them. After getting to know a heat gun really well he ended up with 1500 working relays with which to play. The machine runs slowly, it iss noisy, but it definitely works. After the break you can see it running and assembly code program that he wrote.

The instruction set is based on boards running microcode. These store the operational commands for each instruction the processor has available to it and they run in parallel with the rest of the operations.

We’re always surprised to see that these home-built processors work. Mostly because of the complexity involved in assembling them. How hard is it to find a shorting connection or a malfunctioning relay? Those problems aren’t limited to this application either, what do you do if a transistor-logic CPU has a malfunctioning chip?

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Breadboarding RAM

November 14, 2010 by Chris Nelson 22 Comments

If you’ve ever wanted to dive in and take a look at how memory hardware is implemented here is a good example of how to implement some latching circuits with ether BJT or CMOS transistors. BJTs require biasing resistors which increases the complexity and power consumption when compared to CMOS. If power consumption isn’t an issue you could certainly make some really fast logic.

Most modern on chip RAM is made using SRAM because it only takes six transistors to implement(vs eight) and is pretty fast. When it comes to density DRAM can get one bit of storage by using a single transistor and capacitor(putting the capacitor underneath he transistor can save even more space). All that said, latches and flip flops are still a very useful (and common) tool when working with digital circuits.

Making Point Contact Transistors

November 5, 2010 by Devlin Thyne 15 Comments

[youtube=http://www.youtube.com/watch?v=vmotkjMSKnI&w=470]

[Jeri Ellsworth] is back at it again. We seem to cover her work a lot here. Her latest video above covers how she created a point contact transistor from a 1N34 germanium cat whisker diode. After opening the glass casing on the diode, she uses sharpened phosphor bronze metal from common electrical connectors as the collector and emitter. A 330 microfarad capacitor charged to 20 volts and then discharged though a 680 ohm resistor to the base and collector leads forms the collector region. Her test jig is a simple oscillator circuit such that a properly formed transistor will start the circuit oscillating and make and audible sound. We look forward to more esoteric knowledge of electronic devices being brought to our attention.

IM-ME USB Dongle Hacking

October 23, 2010 by Mike Szczys 14 Comments

This circuit board is from the USB dongle of a Girl Tech IM-ME. [Joby Taffey] took it apart and poked around to learn its secrets. These dongles come along with the pink pager that has become a popular low-cost hacking platform. But we haven’t seen much done with the dongle itself up until now.

[Joby] used the OpenBench Logic Sniffer to gain some insight on what’s going on here. The board has two chips on it, a Cypress CY7C63803 USB microcontroller which talks to the computer over USB and also communicates over SPI with a Chipcon CC1110 SoC radio. It looks like reprogramming the Cypress chip is a no-go, so he went to work on the CC1110. The inter-chip communications data that he acquired by sniffing the SPI lines gave him all he needed to reimplement the protocol using his own firmware. As a proof of concept he to reflashed the CC1110 and can now send and receive arbitrary commands from the dongle. There’s a tiny video after the break showing a script on the computer turning the dongle’s LED on and off.

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1000W Search Light – Now Build A Bat Signal

October 22, 2010 by Mike Szczys 41 Comments

Forget flashlights, and leave those burning lasers at home, [Ben Krasnow] built a search light using a 1000W xenon arc lamp. That box you see on the side of the trash-can housing countains a starting circuit that shoots 30 kilovolts through the xenon lamp to get it started but it is separate from the power supply. [Ben] started experimenting with the lamp back in April but recently finished the project by using the inverter from an arc welder to get the 50 amps at 20 volts needed when the lamp is on.

The insert on the left of the image above is an outdoor picture of the beam. You can make out a tree at the bottom. Take a look at the video after the break for a full walk-through of the circuitry and some test footage of the finished product.

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