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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Panaplex In A Jar

October 22, 2010 by Caleb Kraft 12 Comments

Check out this home made panaplex display. Panaplex displays are closely related to nixie tubes, but instead of layering individual numbers and lighting them separately, it uses pieces to build the numbers like a digital display. [Lindsay] managed to make one at home, using a jam jar as the vacuum tube. Argon as the gas in the tube gives it a pleasant purple color. We really think the end result is fantastic, you can see some build pictures and a run through of the numbers on the site. Unfortunately there aren’t any videos of the display in action.

[via Makezine]

Add Supercaps To Your Exercise Routine

October 8, 2010 by Mike Szczys 26 Comments

Many exercise machines generate electricity as you pedal or climb in order to run the on-board electronics. Unfortunately if you stop or even slow down too much the juice will die and your exercise program will reset. Wanting to improve on this gotcha, [Mike] cracked open his exercise bike and added some super capacitors.

On the circuit board he found an ATmega128 was in charge of the user interface. He probed the board a little bit and couldn’t find how it was connected to the power regulators. After some additional snooping he found it has its own SOIC regulator separate from the ones that run the display and peripherals. He takes us through the calculations he made before choosing his parts. What he ended up with is a set of three supercaps in series that add about two minutes of juice before the levels drop and the chip resets. The design of the board helped a lot as the high-load electronics (like the LCD screen) are on a separate power bus than the processor.