Month: August 2021

A Cheap Dipole Antenna From an Extension Cord

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Dipoles are a classic builder’s antenna, after all they are usually little more than two pieces of wire and a feedline. But as [Rob] shows us in the video below, there are a few things to consider.

The first thing is where to get the wire. A damaged extension cord donated the wire. That’s actually an interesting idea because you get multiple wires the same length inside the extension cord. Of course, it is easy to just pull the conductors out of the extension cord, but how do you feed it? A small balun converts the unbalanced feed line into a balanced connection for the antenna. Although the title says “free dipole” this balun is commercial and probably cost something unless you happen to already have one. However, building a balun isn’t all that tricky, either if you happen to have a ferrite toroid.

Modified 3D-Printer Solders Through-Hole Components.

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Surface-mount technology has been a fantastic force multiplier for electronics in general and for hobbyists in particular. But sometimes you’ve got no choice but to use through-hole components, meaning that even if you can take advantage of SMDs for most of the design, you still might need to spend a little time with soldering iron in hand. Or not, if you’ve got a spare 3D printer lying around.

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View Yourself as Others See You with the Third Person Camera System

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This camera system lets users see themselves from a different perspective ad they walk around.

A previous attempt

Nearly every human experiences the world with a pair of eyes that are only in one position for their entire lives. TurkeyDev wanted to change this by creating a VR device that allows people to see themselves in the world from a different perspective. In his first attempt at creating this system, TurkeyDev began by taking a DIY Google Carboard VR headset and pairing it with a Raspberry Pi camera, but in doing so ran into several issues. The main problems with this initial setup was the lack of a good, solid headset and too much latency which could cause motion sickness.

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Minicomputer Part 5: Building an Arduino ROM Reader

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In this episode we take our first step towards ensuring that we have a backup plan if all the magic smoke comes out on first power up – we rip the data off the ROMs! It’s not as easy as it sounds though as these ROMs are pretty old and weird chips that aren’t supported by a lot of ROM programmers out there, so in the end, we end up building our own ROM reader from scratch using an Arduino and some 74LS161s!

Meet RAMBO, the U.S. Army’s 3D-Printed Grenade Launcher

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The U.S. Army has built and fired an almost entirely 3D-printed 40mm grenade launcher. Scientists and engineers hope the prototype will set the stage for projects in the laboratory and on the battlefield.

The Armament Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal in New Jersey modeled the proof-of-concept Rapid Additively Manufactured Ballistics Ordnance (RAMBO) on the Army-standard M203 grenade launcher and marked it “M203XX.” The production process for 90 percent of the components was at least partially automated, though engineers had to assemble the final weapons by hand. Certain springs and fasteners were too small and complex for a 3D printer. The project also produced training rounds based on the M781, but engineers had to manually add the explosive propellant right before the test shots.

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YouTuber Proves Watercooling a CPU Air Cooler Works (Really Well)

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When it comes to cooling your desktop PC’s processor there’s two main options: air cooling and water cooling. Air coolers are the simpler and more popular option, but can be noisy, where as watercooling can be near silent with a good pump while allowing you to push your chip harder.

But what about combining both? YouTuber Major Hardware decided to find out if such a thing would work.

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DIY Si47xx All Band DSP Radio with 2.8 Inch Touch Display

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This time I will show you how to make a relatively simple All band Radio Receiver which is based on the Si47xx series chip of Silicon Labs. This wonderful radio is is primarily a result of the hard work of Ricardo Caratti who creates the detailed library for the Si47xx chip, Gert Baak for the initial TFT code, and Thiago Lima which creates the Kit with a TFT touch display.

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This Unique Seven-Segment Display Uses a Single Motor to Change Its Digits

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By integrating a pair of special wheels internally, the segments can be raised and lowered at will to produce certain digits.

The idea

For many years now, hobbyists have been trying to come up with increasingly unique and novel ways to display information. These have ranged from giant LED matrices to fun machines that rotate plastic panels in order to create various shapes. In this project created by Instructables user gzumwalt, he was able to build a large seven-segment panel that utilizes seven plastic panels which raise up or down to show a digit. However, unlike many other designs, this one only requires a single stepper motor instead of seven, making it much more easily scaled and cheaper overall.

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Meet your new table tennis coach, a tinyML-powered paddle!

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Shortly after the COVID-19 pandemic began, Samuel Alexander and his housemates purchased a ping pong set and began to play — a lot. Becoming quite good at the game, Alexander realized that his style was not consistent with how more professional table tennis players hit the ball, as he simply taught himself without a coach. Because of this, he was inspired to create a smart paddle that uses an integrated IMU to intelligently classify which moves he makes and correct his form to improve it over time. 

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