This little DIY 64×64 graphical printer by [Egor] is part pen plotter in design, somewhat dot matrix-ish in operation, and cleverly designed to use unmodified 9G servos. The project page is all in Russian (translation to English here) but has plenty of photos that make the operation and design clear. Although nearly the entire thing is made from laser-cut wood, [Egor] says that a laser cutter is optional equipment. The first version was entirely cut with hand tools.
Small DIY CNC machines driven over a serial line commonly use Arduinos and CD-ROM drive guts (like this Foam Cutter or this Laser Paper Cutter) but this build uses its own custom rack-and-pinion system, and has some great little added details like the spring-loaded clip to hold paper onto the print pad.
The frame and parts (including all gears) are laser-cut from 4 mm plywood and the unit is driven by three small servos. A simple Java program processes images and an Arduino UNO handles the low-level control. A video of everything in action is embedded below.
Continue reading “DIY Mini Printer Is 95% Wood, Prints Tiny Cute Images”
Neon lights are that kind of nostalgic item that everybody seems to love. The neon lamp is a type of gas discharge lamp, they generate light when an electrical discharge travels through an ionized gas, or plasma. When the voltage between the electrodes exceeds certain threshold, the gas ionizes and begins conducting electricity. The basic process that generates light is the return of the ions to the ground energy state, with the emission of a photon of light. The light color depends on the emission spectra of the atoms in the gas, and also on the gas pressure, among other variables. Gas discharge lamps can be classified by the pressure of the gas:
- Low pressure: includes the neon lamp, fluorescent lamps and low pressure sodium lamps.
- High pressure: such as the metal halide, high pressure sodium and mercury vapor lamps.
Another classification comes from the heating method of the cathode:
- Hot cathode lamps: the electric arc between the electrodes is created via thermionic emission, where electrons are expelled from the electrodes because of the high temperature.
- Cold cathode lamps: In these, the electric arc results from the high voltage applied between the electrons, that ionizes the gas and conduction can take place.
High intensity lamps are another type of gas discharge lamp where a high power arc is formed between tungsten electrodes. Power levels of several kilowatts can be easily produced this type of lamp. Of course we can’t forget to mention nixie tubes, which are a type of cold cathode neon lamp, popular for building retro clocks. Fortunately, they are now in production again.
Continue reading “The Many Uses Of The Neon Lamp”
[CNLohr] needs no introduction around these parts. He’s pulled off a few really epic hacks. Recently, he’s set his sights on writing a simple, easy to extend library to work with the HTC Vive VR controller equipment, and in particular the Watchman controller.
There’s been a lot of previous work on the device, so [Charles] wasn’t starting from scratch, and he live-streamed his work, allowing others to play along. In the process, two engineers who actually worked on the hardware in question, [Alan Yates] and [Ben Jackson], stopped by and gave some oblique hints and “warmer-cooler” guidance. A much-condensed version is up on YouTube (and embedded below). In the links, you’ll find code and the live streams in their original glory, if you want to see what went down blow by blow. Code and more docs are in this Gist.
Continue reading “[CNLohr] Reverses Vive, Valve Engineers Play Along”
Any amateur radio operator who is living under a homeowner’s association, covenant, or has any other deed restriction on their property has a problem: antennas are ugly, and most HOAs outright ban everything from 2-meter whips to unobtrusive J-pole antennas.
Earlier this year, the ARRL got behind a piece of legislation called the Amateur Radio Parity Act. This proposed law would amend FCC’s Part 97 rules for amateur stations and direct, ‘Community associations to… permit the installation and maintenance of effective outdoor Amateur Radio antennas.’ This bill passed the US House without objection last September.
Last week, the Amateur Radio Parity Act died in the US Senate. Sen. Bill Nelson (D-FL), the ranking member of the Senate committee on Commerce, Science, and Transportation, refused to move the bill forward in the Senate. The ARRL has been in near constant contact with Senator Nelson’s office, but time simply ran out before the end of the 114th Congress. The legislation will be reintroduced into the 115th Congress next year.