Author: Bryan Cockfield

1827 Articles

Lock Your Keys In The Car On Purpose With Aluminum Foil

April 22, 2020 by 74 Comments

[TJ] is a surfer, and drives his car to get to the beach. But when he gets there he’s faced with a dilemma that most surfers have: either put his key in your baggies (shorts) or wetsuit and hope it doesn’t get lost during a wipeout, or stash it on the rear wheel of his car. Hiding the keyfob by the car isn’t an option because it can open the car doors just by being in proximity to the car. He didn’t want to risk losing it to the ocean either, so he built a waveguide of sorts for his key out of aluminum foil that lets him lock the key in the car without locking himself out.

Over a series of trials, [TJ] found out that his car, a 2017 Chevy Cruze, has a series of sensors in it which can determine the location of the keyfob based on triangulation. If it thinks the keyfob is outside of the car, it allows the door to be locked or unlocked with a button on the door handle. If the keyfob is inside the car, though, it prevents the car from locking via the door handles so you don’t accidentally lock yourself out. He found out that he could “focus” the signals of the specific sensors that make the car think the keyfob is outside by building an open Faraday cage.

The only problem now is that while the doors can be locked, they could also can be unlocked. To solve that problem he rigged up an ESP32 to a servo to open and close the opening in the Faraday cage. This still means there’s a hidden device used to activate the ESP32, but odds are that it’s a cheaper device to replace than a modern car key and improves security “through obscurity“. If you have any ideas for improving [TJ]’s build, though, leave them in the comments below. Surfers across the world from [TJ] to the author would be appreciative.

KVM Uses Many Arduinos

April 19, 2020 by 43 Comments

The Arduino platform is one of the most versatile microcontroller boards available, coming in a wide variety of shapes and sizes perfect for everything from blinking a few LEDs to robotics to entire home automation systems. One of its more subtle features is the ability to use its serial libraries to handle keyboard and mouse duties. While this can be used for basic HID implementations, [Nathalis] takes it a step further by using a series of Arduinos as a KVM switch; although admittedly without the video and mouse functionality yet.

To start, an Arduino Uno accepts inputs from a keyboard which handles the incoming serial signals from the keyboard. From there, two Arduino Pro Micros are attached in parallel and receive signals from the Uno to send to their respective computers. The scroll lock key, which doesn’t do much of anything in modern times except upset Excel spreadsheeting, is the toggle switch between the two outputs. Everything is standard USB HID, so it should be compatible with pretty much everything out there. All of the source code and schematics are available in the project’s repository for anyone who wants to play along at home.

Using an Arduino to emulate a USB input device doesn’t have to be all work and no play, the same basic concept can also be used to build custom gaming controllers.

Enforce Social Distancing With High Voltage

April 19, 2020 by 61 Comments

When getting parts together for a one-off project, we often find ourselves with some leftovers on hand. Most of the time these things go in the junk drawer, but [Brad] aka [AtomicZombie] was working on a project which required parts salvaged from several microwave ovens. That left him with enough surplus components to build a social distancing enforcement tool for the modern age; which will deliver a taser-like shock to anyone which violates the new six-foot rule.

The leftover parts in question were built around a high-voltage capacitor, which [Brad] strapped to his back to hold all of the electronics needed for the six-foot electrified hoop. The generator utilizes the output voltage from two magnetrons, but doesn’t start until the operator enters a code on the front control panel, which is about the only safety device on this entire contraption. To get power to the magnetrons a 12 VDC car battery is used with an inverter to get the required input voltage, and towards the end of the video linked below he shows its effectiveness by setting various objects on fire with it.

While this gag project is unlikely to get any actual use, it’s not like any of us around here need an excuse to play with high voltages. [Brad] is also unlikely to need it either; he lives on a secluded 100-acre homestead and has been featured here for some of the projects he built to make his peaceful life a little easier, like a robotic laundry line, mobile chicken coop, and an electric utility tricycle built from an old truck and motorcycle.

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Get Back Out There, Robotically

April 18, 2020 by 8 Comments

When interacting with reality at a distance is the best course of action, we turn to robots. Whether that’s exploring the surface of Venus, the depths of the ocean, or (for the time being) society at large, it’s often better to put a robot out there than an actual human being. We can’t all send robots to other planets, but we can easily get them in various other places with telepresence robots.

This tiny telepresence robot comes to us from [Ross] at [Crafty Robot] who is using their small Smartibot platform as a basis for this tiny robot. The smartibot drives an easily-created cardboard platform, complete with wheels, and trucks around a smartphone of some sort which handles the video and network capabilities. The robot can be viewed and controlled from any other computer using a suite of web applications that can be found on the project page.

The Smartibot platform is an inexpensive platform that we’ve seen do other things like drive an airship, and the creators are hoping that as many people as possible can get some use out of this quick-and-easy telepresence robot if they really need something like this right now. The kit seems like it would be useful for a lot of other fun projects as well.

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’54 Motorcycle Saved By Electric Conversion

April 17, 2020 by 29 Comments

While it’s nice to be able to fully restore something vintage to its original glory, this is not always possible. There might not be replacement parts available, the economics of restoring it may not make sense, or the damage to parts of it might be too severe. [onyxmember] aka [Minimember Customs] was in this position with an old ’54 Puch Allstate motorcycle frame that he found with no engine, rusty fuel tank, and some other problems, so he did the next best thing to a full restoration. He converted it to electric.

This build uses as much of the original motorcycle frame as possible and [onyxmember] made the choice not to weld anything extra to it. The fuel tank was cut open and as much rust was cleaned from it as possible to make room for the motor controller and other electronics. A hub motor was laced to the rear wheel, and a modern horn and headlight were retrofitted into the original headlight casing. Besides the switches, throttle, and voltmeter, everything else looks original except, of course, the enormous 72V battery hanging off the frame where the engine used to be.

At a power consumption of somewhere between three and five kilowatts, [onyxmember] reports that this bike likely gets somewhere in the range of 55 mph, although he can’t know for sure because it doesn’t have a speedometer. It’s the best use of an old motorcycle frame we can think of, and we also like the ratrod look, but you don’t necessarily need to modify a classic bike for this. A regular dirt bike frame will do just fine.

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As A Matter Of Fact, It’s All Dark

April 16, 2020 by 41 Comments

While the dark side of the moon wasn’t seen by humans until the middle of the 20th century, that side of the moon isn’t always dark, just hidden from view of Earth by a quirk of gravity. The more appropriate name for the other half of the moon is the “far side”, but while it gets just as much sunshine as the near side does it is dark to one thing in particular: man-made radio waves. That, along with the lack of an atmosphere and ionosphere on the moon, makes it a perfect place for a new telescope.

This telescope isn’t like something you’d set up in your back yard, either. It’s more similar to the Aricebo Observatory in Puerto Rico which uses natural topography to help form the telescope. The proposed telescope on the far side of the moon would use a robot to deploy a net along a fairly large crater to act as a parabolic dish, while another robot would suspend the receiver above the crater. The large size is necessary for viewing deep into space, but is also because of the low-frequency radio signals they hope to capture.

Building a dish like this on the moon is sure to be no easy task, especially since remote control on the far side of the moon is difficult for precisely the reasons that make this a good location for a telescope. But with an appropriate amount of funding and some sufficiently autonomous robots it should be possible. Plus, you never know what you’ll find when looking deep into space.

Software-Defined Radio Made Easy

April 11, 2020 by 25 Comments

Just a few decades ago, getting into hobby radio meant lots of specialty hardware, and making changes to your setup to work on various frequencies wasn’t particularly easy. Since software-defined radio (SDR) came onto the scene in an accessible way for most of us, this barrier to entry was reduced significantly and made the process of getting on the air a lot easier. It goes without saying that it does require some software, but [Aaron]’s latest project makes even getting that software extremely simple.

What he has done is created a custom Linux distribution based on Debian, called DragonOS, with the entire suite of SDR programs needed to get up and running. Out of the box, it supports RTL-SDR, HackRF and LimeSDR packages and even includes other fun tools you’ll need like Kismet. There are several video demonstrations of his distribution, including using RTL-SDR for ADS-B reception, and also shows off several custom implementations of the OS in various scenarios on his YouTube channel. The video linked below also shows how to set up the distribution in a virtual machine, so you can run this even if you don’t have a computer to dedicate to SDR.

Getting into SDR has never been easier, and the odds of having something floating around in the junk drawer that you can use to get started are pretty high. The process is exceptionally streamlined with [Aaron]’s software suite. If you’re a little short on hardware, though, there’s no better place to get started than with the classic TV-tuner-to-SDR hack from a few years back.

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