Bike Lock Secures Car

April 11, 2020 by 13 Comments

[Buttim] loses his car a lot, which might sound a little bit like the plot from an early-00s movie, but he assures us that it’s a common enough thing. In a big city, and after several days of not driving one’s car, it can be possible to at least forget where you parked. There are a lot of ways of solving this problem, but the solution almost fell right into his lap: repurposing a lock from a bike share bicycle. (The build is in three parts: Part 2 and Part 3.)

These locks are loaded with features, like GPS, a cellular modem, accelerometers, and in this case, an ARM processor. It took a huge amount of work for [Buttim] to get anything to work on the device, but after using a vulnerability to dump the firmware and load his own code on the device, spending an enormous amount of time trying to figure out where all the circuit traces went through layers of insulation intended to harden the lock from humidity, and building his own Python-based programmer for it, he has basically free reign over the device.

To that end, once he figured out how it all worked, he put it to use in his car. The device functions as a GPS tracker and reports its location over the cellular network so it can’t become lost again. As a bonus, he was able to use the accelerometers to alert him if his car was moving without him knowing, so it turned into a theft deterrent as well. Besides that, though, his ability to get into the device’s firmware reminded us of a recent attempt to get access to an ARM platform.

Unique Musical Instrument Defies Description

April 11, 2020 by 17 Comments

Since the first of our ancestors discovered that banging a stick on a hollow log makes a jolly sound, we hominids have been finding new and unusual ways to make music. We haven’t come close to tapping out the potential for novel instruments, but then again it’s not every day that we come across a unique instrument and a new sound, as is the case with this string-plucking robot harp.

Named “Greg’s Harp” after builder [Frank Piesik]’s friend [Gregor], this three-stringed instrument almost defies classification. It’s sort of like a harp, but different, and sort of like an electric guitar, but not quite. Each steel string has three different ways to be played: what [Frank] calls “KickUps”, which are solenoids that strike the strings; an “eBow” coil stimulator; and a small motor with plastic plectra that pluck the strings. Each creates a unique sound at the fundamental frequency of the string, while servo-controlled hoops around each string serve as a robotic fretboard to change the notes. Sound is picked up by piezo transducers, and everything is controlled by a pair of Nanos and a Teensy, which takes care of MIDI duties.

Check out the video below and see if you find the sound both familiar and completely new. We’ve been featuring unique instruments builds forever, from not-quite-violins to self-playing kalimbas to the Theremincello, but we still find this one enchanting.

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LIDAR Built On Familiar Platform

April 11, 2020 by 7 Comments

Moore’s law may have reached its physical limit for transistor density, but plenty of other technologies are still on that familiar path of getting smaller and smaller as time passes. It looks like LIDAR is no exception to this trend either. This project from [Owen] shows a fully-functional LIDAR system for about $20 and built almost entirely on top of an ESP32.

The build uses a Time-Of-Flight IR laser range sensor controlled by the ESP32, and the sensor is much smaller than even the ESP32’s footprint so it takes up very little extra space. To get it to function as a LIDAR system instead of just a simple rangefinder it does need a motor in order to rotate itself to see its entire space. Besides its small form factor and low cost, it also has a handy user interface that can run anywhere an HTML5 browser can run, making the use of the system easy and straightforward as well. All of the code is available on the project’s GitHub page.

We wouldn’t expect a system like this to be driving an autonomous car anytime soon, it’s update rate is far too slow, but its intent for small robots and even as an educational demo for learning LIDAR is second to none. If you do need a little more power in a LIDAR system but still don’t want to break the bank, we featured this impressive setup a few weeks ago.

Table Tennis Ball Lamp Serves Up Style

April 11, 2020 by 5 Comments

Although RGB LEDs diffused by ping pong balls will probably never stop being cool, [thomasj152] feels that flat panels of balls have become a bit of a tired concept. After a lot of effort and two complete builds, he has spun up an 80-ball spherical lamp. The results are positively glowing!

All the balls are connected together with some clever 3D printed pieces that were inspired by the classic soccer ball layout of hexagons and pentagons. [thomasj152] chose this shape because it’s fairly easy to code animation sequences for it.

The design also breaks down nicely into two halves, which makes it easier to wire. All 80 of the balls are controlled with a single NodeMCU ESP8266 development board.

This stranded version is the second lamp [thomasj152] built. The first one used the same soccer ball style, but had RGB LED strips instead, and the balls were wrangled with laser-cut support pieces. Strips lay much flatter than strands do, leaving the inside tidy and spacious. Unfortunately, the LED strips got fried accidentally, which is extra sad because the strips version looks like way more work.

The bright spot here is that [thomasj152] can now provide instructions for both versions. He even has code that cycles through each pentagon and hexagon section, lighting them up one at a time for testing and sanity checks. Roll past the break for a walk-through video that shows both versions and explains the differences.

Got a bunch of wall space begging for blinkenlights? Apparently it’s possible to throw together a working 300-ball video wall in less than 24 hours. Who knew?

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The Key To This City Opens A Real Lock

April 11, 2020 by 6 Comments

There are few more satisfying moments than the first time you pick a lock. No matter that it’s a dollar-store padlock that you opened with a pick from a $10 eBay kit, the magic of something that should be secure clicking open in the palm of your hand is hard to beat. Pin tumbler locks are surprisingly simple devices, and to demonstrate this [Farmcraft 101] has produced one at 10x scale to demonstrate their operation on the bench.

The video is a delightful exercise in wood-shop voyerism, as we see him construct the various parts of the lock using his lathe and other workshop tools. A key of the size usually reserved for Freedom Of The City is made, but this one really does slide into the keyway and operate those pins. At the back is a latch mechanism, and the result is a fully-functional model that anyone should be able to use to figure out how the lock works.

Thelock itself isn’t the whole story though, because given the date he’s used it as the basis for a cracking April Fool in which he sends up the [Lock Picking Lawyer] and proceeds to demonstrate the glaring insecurities in his creation. Both videos are there for your enjoyment, below the break. And if you can’t wait to have a go at a lock or two, don’t forget you can always make your own tools using paperclips.

[Ed note: streetcleaner bristles. Thank me later.]

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Harvesting Energy From Ambient Moisture

April 11, 2020 by 24 Comments

Generating electricity out of thin air is the fantasy for our modern technology dependant world, but still falls squarely in the world of science fiction. However, researchers from the University of Massachusetts Amherst claim that they have found a way to do exactly that, using protein nano-wires to produce tiny amounts of electricity from ambient humidity.

The protein nano-wires in question are harvested from the microbe Geobacter sulfurreducens, to create a 7 µm thick film that is placed between two gold electrodes. One electrode completely covers the back of the film, while the front electrode covers only a tiny portion of the surface area. When the film is exposed ambient moisture, researchers measured 0.4 V – 0.6 V produced continuously for more than two months. The current density was about 17 µA/cm². This is only a fraction of the output of a commercial solar panel, but it can be layered with air gaps in between. The electricity is supposedly produced due to a moisture gradient through the thickness of the film. Harvesting energy using ambient humidity is not new, but the improvement in power density on this study is at least two orders of magnitude larger than that of previous studies.

The researches have named the technology Air-Gen and hope to develop it commercially. As we have seen many times before, promising lab results often don’t translate well into real world products, but this technology is definitely interesting.

We’ll continue to see all sorts of weird and wonderful ways to free up electrons, like using sweat, but we’ll have to wait and see what sticks.

Thanks for the tip [William Polo]!

Planetary Gears Tell Time In This Ornamental Clock

April 10, 2020 by 8 Comments

A clock is perhaps one of the the most popular projects among makers. Most designs we see are purely electronic and do not bother with the often more complicated mechanical part. Instructables user [Looman_projects] though was not afraid of calculating gear ratios and tooth counts for his planetary gear clock.

As shown in the picture, a planetary gear, also known as epicyclic gear, consists of three parts: a central sun gear, planetary gears moving around the sun gear and an outer ring with inward-facing teeth holding it all together. The mechanism dates back to ancient Greece but is still being used in car transmissions and has become quite popular in 3D printing. In his instructable [Looman_projects] has some useful inlinks including an explanation video of how planetary gear sets work and a website helping you to calculate the tooth counts for specific gear ratios. It is also noteworthy that he tried to cut the gears from aluminum with a waterjet which unfortunately failed because the parts were too small. What makes the clock visually stand out is the beautiful ornamental see-through design of the dial plate and hands made from laser-cut wood. Despite the mechanical gearbox, it is not surprising that the driving mechanism is based on ubiquitous pieces of digital electronics including an Arduino Nano, DS3231 RTC module, and a stepper motor. To avoid a cabling mess [Looman_projects] designed a custom PCB that interconnects all the electronics and says he even got some spare PCBs left for people interested in rebuilding the clock.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D printed version is lifting an anvil.

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