Kenington has produced several models of "Universal Power Supplies" for use with laptop computers and various other pieces of gear.  These power supplies use a special tip which controls the voltage and current for the connected device.  It may surprise you that one of these power supplies can make an excellent bench power supply, with voltage adjustable from 0 - 24 volts at up to 6 amps.  Additionally, the current can be limited, either for safety (so a short doesn't blow up your widget) or to use as a constant current supply (no matter what the load, the current will remain constant).  Constant current supplies are perfect for charging batteries or characterising LEDs.

I found one of these supplies at the local thrift store for $6 and couldn't pass it up.  Since the supply is adjustable and the voltage and current are controlled by the small tip adapters, I knew the process couldn't be too difficult and I guessed it would be controlled by resistors in the tip.

I got lucky.  A little time with Google found exactly the information I needed on the dorkbotpdx forum.  Thanks goes out to Dave, who wrote:

[Aurthor's Note: I wrote this article several years ago for another website.  The information is still accurate.  "Doug In The Woods" wrote to my Clever4Hire email address asking for some guidance, so this seemed like a useful reference to republish.]

Having your own web site used to be a daunting task, beyond the reach of casual users. Expensive hardware and software or costly hosting services were required to get a web site on line. Design of a web page required complicated software and an extensive knowledge of HTML to design nice looking pages.

I'm happy to report that recent technology has changed this situation so that nearly anyone can afford to have a nice looking web site! You might be surprised to learn that the total cost to have your own web page is only about $10/year! And no costly software is required to create the pages for the site.

Domain registration, hosting, page creation software? How can the web site cost only $10/year?

Introducing the Led Breadcrumb (Led8Bus).

Are you fed up of fitting LEDs and current-limiting resistors time after time into your breadboard? It's surprising how often you have to do it, and how much room they take up. Well, this tiny little module is the answer.

At about the same size as a 16 pin DIP IC, this module has 8 individual surface mount (0805) LEDs along with 470Ω current limiting resistors (that's for 5V operation) and a common cathode connection

Dave's got another great video on how to use a simple push-button switch as an on/off power switch.  Using this circuit can save the cost of a high-current toggle switch and makes a very clean user interface.  As usual, Dave carefully explains the details of the circuit in a clear, concise manner.

Watch the video for complete details.

Back in 2008, David Barker released a partial port of the Microchip ethernet libraries. At the time I excitedly looked at it, then promptly forgot about it.

Fast forward to now, and I rediscovered the stack, lurking about at the bottom of my UserLibrary. Having powered up my PICDEM.net2 board and uploaded the demo samples, I lamented the lack of a HTTP client.