Collaborate Disseminate
Rim-driven thrusters turn the normal propeller-motor arrangement inside out; rather than mounting the motor at the center of the propeller, they use a large hollow motor, with the blades attached …read more Continue reading Building a Rim-Driven Jet Engine
Capacitive displacement sensors span a wide range of resolution, from the touchscreen sensors which can only detect displacement as a binary state, all the way to the sensors in semiconductor …read more Continue reading Using Capacitance for Extremely Sensitive Proximity Sensing
Of all the remote-control vehicles one can build, a submarine is possibly the hardest: if something goes wrong with almost any other vehicle, it’s easy to recover and repair, but …read more Continue reading 3D-Printed Parts Nearly Sink RC Submarine
There’s a long history of devices originally used for communication being made into computers, with relay switching circuits, vacuum tubes, and transistors being some well-known examples. In a smaller way, …read more Continue reading A Suction-Driven Seven-Segment Display
Everything on the electromagnetic spectrum has some properties of both waves and particles, but it’s difficult to imagine a radio wave, for example, behaving like a particle. The main evidence …read more Continue reading Testing the Wave-Particle Duality with Gamma Rays
Old shop tools have a reputation for resilience and sturdiness, and though some of this is due to survivorship bias, some of it certainly comes down to an abundance of …read more Continue reading Building a Vise Stand with Pen-Like Retracting Wheels
The basic principle of radar systems is simple enough: send a radio signal out, and measure the time it takes for a reflection to return. Given the abundant sources of …read more Continue reading Using a Scientific Satellite for Passive Radar
Usually, when we see non-planar 3D printers, they’re rather rudimentary prototypes, intended more as development frames than as workhorse machines. [multipoleguy]’s Archer five-axis printer, on the other hand, breaks this …read more Continue reading Multicolor 5-Axis 3D Printing
An MRI scan is never a pleasant occasion – even if you aren’t worried about the outcome, lying still in a confined, noisy space for long periods of time is …read more Continue reading Building a Laser-Driven Photoacoustic Speaker
Although the RTL-SDR is cheap, accessible, and capable enough for many projects, it does have some important limitations. In particular, its bandwidth is limited to about 3.2 MHz, and the …read more Continue reading Building a $50 SDR with 20 MHz Bandwidth