Aquarium water exchanger

fish-tank-water-exchanger

If you want happy fish you're going to need to do regular aquarium maintenance. Part of this is exchanging a portion of the tank's water on a regular basis. [Bill Porter] came up with a water exchanger that means less manual labor, but makes the process just a bit more complicated. So, what he would do before is fill a few buckets from the aquarium and dump them down the toilet. Then mix up a … [Read more...]

Nokia internet key external antenna

nokia-wind-external-antennae

[Maurizio] was having some reception issues with his wireless internet and set out to add an external antenna to the USB dongle (translated). He had previously poked around inside of the Nokia internet key to find that the internal antenna was a flexible circuit substrate wrapped around a plastic box that made contact with main circuit board via a spring connector. This plastic frame is just right … [Read more...]

Tri-rotor helicopter with full autopilot

tri-rotor-copter-with-autopilot

Quadcopters stand aside, here's a three-rotor helicopter we think you're going to love. The body is made out of plywood and carbon fiber rods, keeping it light enough to be easily lifted by just 3 motors while making sure the force doesn't tear the aircraft apart. Three gyroscopes, two accelerometers, three magnetometers, and a GPS module are all used in conjunction for an autopilot system. … [Read more...]

Is your camera lying?

IMG_0972

It is easy to rely on the ratings marked on different tools, whether it is a power supply, scale, or speedometer. However calibration is essential for any part that is relied upon either professionally or for a hobby. [Jeremy] wanted to see if his Lomography camera shutter really was only open for 1/100ths of a second when set to that. In order to test his rig, he set up an LED on one side of … [Read more...]

Audio Crossover Back in Service

KlipschAA

Audio Crossovers are an essential tool for any high end speaker system. Because most individual loudspeakers are unable to cover the entire spectrum of audible sound as well as multiple drivers are, it is necessary to split the input signal into low and high frequency parts. When a friend of [Anthony]'s was about to send off a classic Klipsch AA Crossover to be repaired professionally, [Anthony] … [Read more...]

Electronic dice has option for 20 or 100 sides

100-sided-dice

[Bluewraith] built himself an electronic dice using a 555 timer and 4017 counter. This is a classic project and he enjoyed doing it but wondered about making a 20-sided dice. So he grabbed his Arduino and got to work. A switch on the final project selects between 20 or 100 sides. He used a MAX7219 to control the 7-segment displays, and a standalone AVR chip for the rest of it. If you missed it … [Read more...]