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Hardware hacking how-tos

Making Metal Dominoes

April 11, 2017 by 14 Comments

Nearly as versatile as a deck of playing cards, dominoes are a great addition to any rainy-day repertoire of game sets. [Apollo] from the Youtube channel [carbide3d] has manufactured for themselves a custom set of domino tiles replete with brass pips.

Cutting the bar stock to the appropriate size, [Apollo] ran a few test engravings and hole sizes for the brass pips. That done, all they had to do was repeat the engraving and milling process another couple dozen times, as well as all the requisite wet and dry sanding, and buffing. [Apollo] opted to use paint marker to add a little extra style to the tiles, and advises any other makers who want to do the same to set their engraving depth to .01″ so  the paint marker won’t be rubbed off when buffing the pieces.

When it came to installing the brass balls, [Apollo] undersized the holes by .001″-.002″ for a snug press fit — adding that the hole depth is a little greater than half the ball’s diameter. They used 1/8″ balls for the pips, and 3/16 balls for the center of the tiles which also allows the tiles to be spun for a bit of fidgeting fun during play. Check out the build video after the break.

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Wirelessly Charge Your Phone From High Voltage Power Lines

April 10, 2017 by 103 Comments

Using nothing more than an antenna, a spark plug, a flyback transformer, a diode, and a car phone charger, [Kreosan] have implemented the world’s most dangerous cell-phone charger: wirelessly charging their phone from high voltage power lines. This is a demonstration of a hack that we thought was just an urban legend, but it’s probably best to leave this as just a demo — this one is probably illegal and definitely dangerous.

The charger works by holding an old TV aerial fairly close to high voltage overhead cables, and passing the resulting tiny current through a spark plug and a flyback transformer to ground. To charge the phone, they tapped the transformer, rectified it through a diode, and fed it into a car-plug phone charger. [Kreosan] claims to harvest enough “free” electricity to charge the phone. (Where by “free”, we mean stolen from the electric grid.)

If you regularly find yourself running out of charge and like a bit of danger why not make a power bank that looks like a bomb instead. Sure we don’t advise you take it on a plane but it seems like a much safer option than using overhead power lines.

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Learn Neural Network And Evolution Theory Fast

April 5, 2017 by 32 Comments

[carykh] has a really interesting video series which can give a beginner or a pro a great insight into how neural networks operate and at the same time how evolution works. You may remember his work creating a Bach audio producing neural network, and this series again shows his talent at explaining the complex topic so anyone may understand.

He starts with 1000 “creatures”. Each has an internal clock which acts a bit like a heart beat however does not change speed throughout the creature’s life. Creatures also have nodes which cause friction with the ground but don’t collide with each other. Connecting the nodes are muscles which can stretch or contract and have different strengths.

At the beginning of the simulation the creatures are randomly generated along with their random traits. Some have longer/shorter muscles, while node and muscle positions are also randomly selected. Once this is set up they have one job: move from left to right as far as possible in 15 seconds.

Each creature has a chance to perform and 500 are then selected to evolve based on how far they managed to travel to the right of the starting position. The better the creature performs the higher the probability it will survive, although some of the high performing creatures randomly die and some lower performers randomly survive. The 500 surviving creatures reproduce asexually creating another 500 to replace the population that were killed off.

The simulation is run again and again until one or two types of species start to dominate. When this happens evolution slows down as the gene pool begins to get very similar. Occasionally a breakthrough will occur either creating a new species or improving the current best species leading to a bit of a competition for the top spot.

We think the series of four short YouTube videos (all around 5 mins each) that kick off the series demonstrate neural networks in a very visual way and make it really easy to understand. Whether you don’t know much about neural networks or you do and want to see something really cool, these are worthy of your time.

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Cordless Water Pump!

April 2, 2017 by 28 Comments

A water pump is one of those items that are uncommonly used, but invaluable when needed. Rarer still are cordless versions that can be deployed at speed. Enter [DIY King 00], who has shared his build of a cordless water pump!

The pump uses an 18 volt brushed motor and is powered by an AEG 18V LiPo battery. That’s the same battery as the rest of [DIY King]’s power tools, making it convenient to use. UPVC pipe was used for the impeller — with a pipe end cap for a housing. A window of plexiglass to view the pump in motion adds a nice touch.

A bit of woodworking resulted in the mount for the pump and battery pack, while a notch on the underside allows the battery to lock into place. Some simple alligator clips on the battery contacts and the motor connected through a switch are all one needs to get this thing running.

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Don’t Fear The Filter: Cascading Sallen-Keys

March 29, 2017 by 22 Comments

In the last edition of Don’t Fear the Filter, we built up two examples of the simplest and most-used active filter of all time: the two-pole Sallen-Key lowpass. This time, we’re going to put two of these basic filter blocks in a row, and end up with a much sharper lowpass filter as well as a bandpass filter. For the bandpass, we’ll need to build up a quick highpass filter as well. Bonus!

I claimed last time that the Sallen-Key lowpass would cover something like 80% of your filtering needs. (And 72.4% of all statistics are totally made up!) These two will probably get you through another 10% or so. Honestly, I’ve never built a standalone active highpass, for reasons we’ll see below, but the active bandpass filter that we’re building it for is a great tool to have in your belt, especially for anything audio.

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Source Parts On TaoBao: An Insider’s Guide

March 28, 2017 by 60 Comments

For hardware aficionados and Makers, trips to Shenzhen’s Huaqiangbei have become something of a pilgrimage. While Huaqiangbei is a tremendous and still active resource, increasingly both Chinese and foreign hardware developers do their sourcing for components on TaoBao. The selection is vastly greater and with delivery times rarely over 48 hours and frequently under 24 hours for local purchases it fits in nicely with the high-speed pace of Shenzhen’s hardware ecosystem.

For overseas buyers, while the cost of Taobao is comparable to, or slightly less than AliExpress and Chinese online stores, the selection is again, many, many times the size. Learning how to effectively source parts from Taobao will be both entertaining and empowering.

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Turn That Pi Zero Into A Streaming Camera, Step-by-Step

March 26, 2017 by 30 Comments

What makes [mwagner1]’s Raspberry Pi Zero-based WiFi camera project noteworthy isn’t so much the fact that he’s used the hardware to make a streaming camera, but that he’s taken care to document every step in the process from soldering to software installation. Having everything in one place makes it easier for curious hobbyists to get those Pi units out of a drawer and into a project. In fact, with the release of the Pi Zero W, [mwagner1]’s guide has become even simpler since the Pi Zero W now includes WiFi.

Using a Raspberry Pi as the basis for a WiFi camera isn’t new, but it is a project that combines many different areas of knowledge that can be easy for more experienced people to take for granted. That’s what makes it a good candidate for a step-by-step guide; a hobbyist looking to use their Pi Zero in a project may have incomplete knowledge of any number of the different elements involved in embedding a Pi such as basic soldering, how to provide appropriate battery power, or how to install and configure the required software. [mwagner1] plans to use the camera as part of a home security system, so stay tuned.

If Pi Zero camera projects catch your interest but you want something more involved, be sure to check out the PolaPi project for a fun, well-designed take on a Pi Zero based Polaroid-inspired camera.