How-to: Build Your Own Spot Welder

June 23, 2009 by Steve Watkins 85 Comments

Spot welders are used in the fabrication of automobiles, PC cases, power supplies, microwave ovens, electrical junction boxes, Faraday cages, and various electronics. A spot welder is used because it produces a highly defined point of contact weld. The materials are welded without excessive heating, so working pieces are handled easily. The weld is also highly controlled and repeatable. In this how-to we cover the basics of a spot welder, and then show you how to build one from a microwave oven transformer.

Continue reading “How-to: Build Your Own Spot Welder” →

How-to: Fix Your Stupid Internet

April 1, 2009 by Eliot 26 Comments

aprilfools-1

Dear Hack a Day,
Websites keep publishing poorly executed jokes today; how can I fix this?

We’ve been getting a lot of questions on the tip line like the one above, so we put together this one-step illustrated how-to. If you’re not the physical labor type, you can use [Steve Lambert]’s SelfControl.

How-to: Bus Pirate V1, Improved Universal Serial Interface

January 22, 2009 by Ian 65 Comments

front450a

We use the Bus Pirate to interface a new chip without writing code or designing a PCB. Based on your feedback, and our experience using the original Bus Pirate to demonstrate various parts, we updated the design with new features and cheaper components.

There’s also a firmware update for both Bus Pirate hardware versions, with bug fixes, and a PC AT keyboard decoder. Check out the new Hack a Day Bus Pirate page, and browse the Bus Pirate source code in our Google code SVN repository.

We cover the design updates and interface a digital to analog converter below.

Continue reading “How-to: Bus Pirate V1, Improved Universal Serial Interface” →

How-to: Prepare Your Eagle Designs For Manufacture

January 15, 2009 by Ian 47 Comments

back

Cadsoft Eagle is a multi-platform freeware circuit layout program. Lots of open source hardware is designed in Eagle, and it’s become a hobbyist favorite. We use it for all of our hardware designs.

There are several ways to turn an Eagle design into an actual printed circuit board (PCB). We’ll show you how to save Eagle designs as industry-standard gerber files that are accepted by any PCB manufacturer. You can use the gerbers to order a single prototype, or a full panel.

Continue reading “How-to: Prepare Your Eagle Designs For Manufacture” →

How-to: Digital Picture Frame, 100% DIY

January 8, 2009 by Ian 50 Comments

frontii

There are a ton of digital picture frame tutorials out there. Most are old laptops with crafty case reconfigurations that fit a photo frame profile.

We set out to build a 100% DIY, scratch-built digital picture frame. Our frame has a 12bit color LCD, gigabytes of storage on common, FAT-formatted microSD cards, and you can build it at home. We’ve got the details below.

Continue reading “How-to: Digital Picture Frame, 100% DIY” →

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.

Continue reading “How-to: Programmable Logic Devices (CPLD)” →

How-to: Read A FedEx Kinko’s Smart Card (SLE4442)

November 25, 2008 by Ian 28 Comments

Our wallets are filling up with SIM and RFID cards that contain hidden information. Using our latest project, the Bus Pirate universal serial interface, we can dump the memory from many common smart cards. In today’s How-to, we show you how to interface common smart cards, and walk you through the data stored on a FedEx Kinko’s prepaid value card.

Continue reading “How-to: Read A FedEx Kinko’s Smart Card (SLE4442)” →