Building a Robot Contest Arena
Constructing a playing field for robots is much harder than it seems. Here are some tips for cutting wood boards, machining retention lips for scoring areas, chiseling notches, connecting wall together, and filling gaps.

Fighter Pilot Safety-Cover Toggle Switch
See how an illuminated toggle switch works by breaking one open and putting it back together. Most of these are automotive switches, which need 12 V. The circuit schematics on the second page of the article show you how to shift voltage levels from 12 V to 5 V, and 5 V to 12 V. A microcontroller can read the switch state and blink the LED.

PCB Layout Tricks and Tips
A few extra holes, wider pads, and copper fills can greatly increase the versatility, solderability, and ease of testing of the printed circuit boards you design.

Digital Caliper Data Output
How to read the data from a digital caliper. This is useful in making a digital readout (DRO) for machining equipment, for automating measurement recording, or to use a digital caliper as a position sensor in a robotic arm.

Model Rocket Launch Controller
The secrets to a successful launch controller are thick cables, power through a relay, and a beefy battery (such as a lead-acid motorcycle battery). Learn what is inside a low-end commercial rocket launcher, how to make your own simple launch controller, and take a look at a fancy rocket controller that includes covered pilot switches and a switch lock.

Weather Station
Logging six temperatures and solar activity at one minute intervals around the clock using a 4 megabyte serial flash chip. The observation results are graphed to demonstrate weather conditions over multiple days in the Chicagoland area. Ran into some problems with a broken wire, overheating project box, shadows, and exposed sensors.

Solar Recharging
A small solar panel or series of solar cells can power an electronic device during the day, as well as recharge NiMH batteries to power the device at night. This simple recharger uses diodes for reverse-power protection and so that the project can measure the power source voltages. Includes schematics and graphs.

Multimeter Reviews
A digital meter is an essential tool for all robot builders and electronic hobbyists. If you're just starting out, can you buy the least expensive model and still get accurate results? How much do you need to spend to get a decent mid-range model? A dozen multimeters are tested and compared.

Macro Photography
Taking a picture of an electronic part, circuit board, or other small object is much easier if you have the right setup. This includes a DIY remote shutter release, desk lamp ring light, and horizontal tripod arm. Take a peek at the Robot Room digital camera setup.

Searching for Cool Stuff
Help David find components and tools for various projects. Currently searching for an oscilloscope, normally-closed and dual-action tactile buttons, and well as test lead hooks.