Cordless Drill Overhaul

December 13, 2008 by Caleb Kraft 15 Comments

drill_upgrade

[Alexander.m] shows us how to do a major overhaul on a cordless drill, replacing pretty much everything but the case. He needed some more power, but found the price tag of the bigger drills to be prohibitive. He opted for a more hacked together approach and used a 24 volt 1.4 hp hobby motor as a drive. He had to make a custom enclosure for the batteries too. The final result may not be the prettiest thing in the world, with that giant battery pack on the bottom, but it probably gets the job done pretty well and cost less than half of what a new one would have.

How-to: Programmable Logic Devices (CPLD)

December 11, 2008 by Ian 57 Comments

Complex programmable logic devices (CPLDs) contain the building blocks for hundreds of 7400-serries logic ICs. Complete circuits can be designed on a PC and then uploaded to a CPLD for instant implementation. A microcontroller connected to a CPLD is like a microcontroller paired with a reprogrammable circuit board and a fully stocked electronics store.

At first we weren’t sure of the wide appeal and application of CPLDs in hobbyist projects, but we’ve been convinced. A custom logic device can eliminate days of reading datasheets, finding the ideal logic IC combination, and then waiting for chips to arrive. Circuit boards are simpler with CPLDs because a single chip with programmable pin placement can replace 100s of individual logic ICs. Circuit mistakes can be corrected by uploading a new design, rather than etching and stuffing a new circuit board. CPLDs are fast, with reaction times starting at 100MHz. Despite their extreme versatility, CPLDs are a mature technology with chips starting at $1.

We’ve got a home-etchable, self programming development board to get you started. Don’t worry, this board has a serial port interface for working with the CPLD, and doesn’t require a separate (usually parallel port) JTAG programmer.

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Making A Cold Heat Soldering Iron

December 11, 2008 by Caleb Kraft 27 Comments

cold_heat

Cold Heat soldering irons are pretty cool. They heat up in seconds and cool down just as quickly. [photozz] shows us how we can make one from stuff we probably have sitting around right now. Cold Heat soldering irons work off of resistance, the tip material heats very quickly when electricity is passed through the two halves. Upon assessing what he had lying around, [photozz] realized that graphite would work much the same way. He modified a regular soldering iron with a new two piece graphite tip, and powered it with an old pc power supply. The end result is quite nice, though it still needs some kind of temperature control. You may recall seeing other electrical uses for graphite, such as making quick and dirty light.

Parts: 1-Wire Temperature Sensor (DS1822)

December 10, 2008 by Ian 18 Comments

1wire

Download: buspirate.v0d.zip

Dallas/Maxim’s 1-Wire protocol is the most requested addition to the Bus Pirate. We finally got some 1-Wire parts, and today we’ll demonstrate the DS1822 1-Wire digital thermometer. Grab the datasheet (PDF) and follow along.

This post is accompanied by release v.0d of the Bus Pirate firmware for hardware version 0. This includes the new 1-Wire protocol library, more configuration options, and other improvements.

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Acrylic Tumbler Lock

December 9, 2008 by Eliot 21 Comments

acrylictumbler

Sometimes describing how a lock actually works can be the hardest part of teaching someone about lockpicking. [Mike Gee] has designed an acrylic lock that may just be the ticket for these situations. All of the pieces are cut from clear acrylic. As you insert the key, you can see it raise the four pins up to the shear line. He says that it will definitely take some tweaking as you assemble it to get it to function smoothly. Embedded below is a video of the lock in use. You can find plans on Thingiverse.

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Arduino Shield Scaffold

December 6, 2008 by Eliot 11 Comments

arduinoshield

[Garrett] from macetech has been prototyping shields for the Arduino development platform. Arduino’s have an inexplicable nonstandard spacing between two of the banks of output pins. This means that you can’t use regular perfboard with them. To make the design process quicker, [Garrett] has put together an Eagle file that just includes the male header pins. The file also has a line indicating the tall lower board components so you can avoid creating shorts.

Working With Relays

December 5, 2008 by Eliot 24 Comments

relay

SparkFun’s latest tutorial shows you how to work with relays. A relay is an electrically operated switch. In this case, they’re using it to switch a 120V AC outlet. The article carries the standard warnings about how not to kill yourself with AC (plus some non sequitor linking throughout). As an extra precaution, they chose a GFI outlet. You probably know how a relay works, but it’s worth seeing how they implemented it. They use a transistor to prevent overloading the microcontroller’s GPIO pin. The control pin is pulled to ground to keep the relay off. A diode is placed across the relay coil to manage the power flow when it discharges. An indicator LED is included to show when the relay closes. This is a great foundation for an automation project, or maybe you just want to terrorize your cat.