Intel 8008 Clock

July 7, 2009 by Gerrit Coetzee 11 Comments

Every year [Len Bales] designs and builds a new clock. His 2006 clock runs on the classic Intel 8008 microprocessor. The design is definitely not for the faint of heart, but he includes all code, diagrams and a good description on his site. The project is an interesting look into the not-so-distant past of computing. While the function of the project is a clock, it is actually a fully programmable 8008 computer running at 500khz with 16k of memory space and 4io ports. [Len] also links a lot of useful 8008 resources for anyone wanting to tackle a project of their own.

AVR Boost Converter

July 7, 2009 by Zach Banks 19 Comments

avrboost

Over at SpriteMods, [sprite_tm] realized that a microcontroller could be used as a boost converter to power itself. A boost converter steps up voltage from a battery by switching the output of a coil. First, it is tied to ground so a magnetic field can build up in the coil. It is then released as a higher voltage than the input. Normally dedicated chips do this at an incredibly high frequency, but the PWM signal from an AVR works well enough. This can be used in low-power situations where space is an issue.

[via EMSL]

C64 USB Keyboard

July 6, 2009 by Steve Watkins 10 Comments

breadboard

[Maarten] told us about a C64 USB keyboard that was modified to be used as a standard input device. An interesting aspect of the project is the use of V-USB (formerly known as AVR-USB). V-USB is a software only approach to slow speed USB HID. In essence this is a two fold mod, The C64 keyboard is patched to a PC, and an off the shelf AVR is software-hacked to bit bang the USB communications. The author notes an initial problem with multiple key presses that was later corrected in the application. For the other side of the spectrum, we had covered the C64 twittering client, and a commodore 64 laptop.

Parts: Ferrite Beads

July 6, 2009 by Ian 34 Comments

ferrite-bead.ii

Ferrite beads (L1 in the photo) filter high frequency power supply noise by converting it into a tiny amount of heat. Power supply noise can cause various problems for many parts, especially in analog audio and display circuits.

Ferrite beads are simple, but choosing one can be confusing because they’re not commonly used by hobbyists. Most designs will still work if you omit the ferrite bead(s), but beads are so cheap there’s no reason to sacrifice the added reliability they provide. We describe how we pick ferrite beads for our projects after the break.

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Capacitive Discharge Spot Welder Update

July 5, 2009 by Eliot 22 Comments

welder

It seems one of our commenters took great umbrage with [PodeCoet] not documenting his capacitive discharge cutting properly. [PodeCoet] had been waiting till he got the full spot welder working before publishing, but he’s expedited the work after all our whining. Check out his full writeup of the device in its current state. It uses a 1Farad audio cap for storage. A dsPIC monitors all of the voltage sources and regulates charging. A nice touch is the tactile switch on the electrode.

Capacitive Discharge Cutting

July 4, 2009 by Steve Watkins 25 Comments

capacitive discharge cutting

Capacitive discharge cutting provides more control than linear transformer versions. A very large capacitor is charged to a precise voltage and then discharged through the material to produce a controlled cut. The same device can also be used for spot and tab welding. A video of copper roof flashing being cut is embedded below. An example of a linear transformer can be found in our our How-to: build your own spot welder.

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Lego Modded Antenna Tuner

July 3, 2009 by Steve Watkins 15 Comments

legomoddedtunner

This antenna tuner is controlled remotely using geared motors and legos. The tuner needed to be closer to the antenna for performance reasons. This created a problem; most of the radio gear is inside while the tuner is outside. The gear motors and Legos combine to form a closed loop servo, operating two air core caps and an inductor switch. A control box placed near the radio is hard wired to the modded tuner outside. We would like to see something like this under gesture control using the Wii MotionPlus + Arduino.