Balance Box Game Requires A Steady Hand

October 17, 2019 by Lewin Day 3 Comments

In the distant past, engineers used exotic devices to measure orientation, such as large mechanical gyros and mercury tilt switches. These are all still useful methods, but for many applications MEMS motions devices have become the gold standard. When [g199] set out to build their Balance Box game, it was no exception.

The game consists of a plastic box, upon which a spirit level is fitted, along with a series of LEDs. The aim of the game is to keep the box level while carrying it to a set goal. Inside, an Arduino Uno monitors the output of a MPU 6050, a combined accelerometer and gyroscope chip. If the Arduino detects the box is tilting, it warns the user with the LEDs. Tilt it too far, and a life is lost. When all three lives are gone, the game is over.

It’s a cheap and simple build that would have been inordinately more expensive only 10 to 20 years ago. It goes to show the applications enabled by ubiquitous cheap electronics like MEMS sensors. The technology has other fun applications, too – for example the Stecchino game, or this giant balance board joystick. We’re certainly lucky to have such powerful technology at our fingertips!

“The Thing”: A Homemade FPGA Board

October 17, 2019 by Sharon Lin 13 Comments

The Thing is an unassuming name for an ambitious project to build an FPGA board from easy to find components.

The project stems from an earlier build submitted to the 2018 Hackaday Prize by [Just4Fun] where two dev boards – an STM32-based Arduino and an Altera MAX II CPLD board – were combined with the Arduino used as a stimulus generator for the CPLD. This way, the Arduino IDE, interfaced through USB, can be used for programming the CPLD.

The Thing similarly uses the STM32 Arduino as a companion processor for the FPGA, with a 512KB SRAM and common I/O for GPIOs and a PS/2 keyboard for running HDL SOCs. It can also run Multicomp VHDL SOCs, a modular design that was made to run some older 8-bit CPUs made by [Grant Searle].

The FPGA (EP2C5T144C8N) uses the Quartus II IDE for configuration with a USB Blaster dongle through the JTAG or AS connector. The FPGA side controls a 4 digit seven segment LED display, four push buttons, 3 LEDs, a push button to clear all internal FFs (sampling rates), a push button to force a reboot (configuration reload), and a switch to force all pins to Hi-Z mode. Both an onboard 50MHz oscillator and connector for an external oscillator are also present on the FPGA side.

In one demo of the MP/M system capability of the board, The Thing was made to handle four concurrent users with one serial port connector to a PC and terminal emulator and the other serial ports connected to terminal emulators on VT100 boards routed through a dual-channel RS232 adapter board.

Both the Arduino and FPGA sides can also be used as standalone boards, but why use one when you can harness both boards together?

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Worried About Bats In Your Belfry? A Tale Of Two Bat Detectors

October 17, 2019 by Pat Whetman 33 Comments

As somebody who loves technology and wildlife and also needs to develop an old farmhouse, going down the bat detector rabbit hole was a journey hard to resist. Bats are ideal animals for hackers to monitor as they emit ultrasonic frequencies from their mouths and noses to communicate with each other, detect their prey and navigate their way around obstacles such as trees — all done in pitch black darkness. On a slight downside, many species just love to make their homes in derelict buildings and, being protected here in the EU, developers need to make a rigorous survey to ensure as best as possible that there are no bats roosting in the site.

Obviously, the authorities require a professional independent survey, but there’s still plenty of opportunity for hacker participation by performing a ‘pre-survey’. Finding bat roosts with DIY detectors will tell us immediately if there is a problem, and give us a head start on rethinking our plans.

As can be expected, bat detectors come in all shapes and sizes, using various electrickery techniques to make them cheaper to build or easier to use. There are four different techniques most popularly used in bat detectors.

Heterodyne: rather like tuning a radio, pitch is reduced without slowing the call down.
Time expansion: chunks of data are slowed down to human audible frequencies.
Frequency division: uses a digital counter IC to divide the frequency down in real time.
Full spectrum: the full acoustic spectrum is recorded as a wav file.

Fortunately, recent advances in technology have now enabled manufacturers to produce relatively cheap full spectrum devices, which give the best resolution and the best chances of identifying the actual bat species.

DIY bat detectors tend to be of the frequency division type and are great for helping spot bats emerging from buildings. An audible noise from a speaker or headphones can prompt us to confirm that the fleeting black shape that we glimpsed was actually a bat and not a moth in the foreground. I used one of these detectors in conjunction with a video recorder to confirm that a bat was indeed NOT exiting from an old chimney pot. Phew!

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Coandă Effect Makes A Better Hovercraft Than A Quadcopter

October 17, 2019 by Dan Maloney 22 Comments

Leaving no stone unturned in his quest for alternative and improbable ways to generate lift, [Tom Stanton] has come up with some interesting aircraft over the years. But this time he isn’t exactly flying, with this unusual Coandă effect hovercraft.

If you’re not familiar with the Coandă effect, neither were we until [Tom] tried to harness it for a quadcopter. The idea is that air moving at high speed across a curved surface will tend to follow it, meaning that lift can be generated. [Tom]’s original Coandă-copter was a bit of a bust – yes, there was lift, but it wasn’t much and wasn’t easy to control. He did notice that there was a strong ground effect, though, and that led him to design the hovercraft. Traditional hovercraft use fans to pressurize a plenum under the craft, lifting it on a low-friction cushion of air. The Coandă hovercraft uses the airflow over the curved hull to generate lift, which it does surprisingly well. The hovercraft proved to be pretty peppy once [Tom] got the hang of controlling it, although it seemed prone to lifting off as it maneuvered over bumps in his backyard. We wonder if a control algorithm could be devised to reduce the throttle if an accelerometer detects lift-off; that might make keeping the craft on the ground a bit easier.

As always, we appreciate [Tom]’s builds as well as his high-quality presentation. But if oddball quadcopters or hovercraft aren’t quite your thing, you can always put the Coandă effect to use levitating screwdrivers and the like.

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Worn Out EMMC Chips Are Crippling Older Teslas

October 17, 2019 by Tom Nardi 230 Comments

It should probably go without saying that the main reason most people buy an electric vehicle (EV) is because they want to reduce or eliminate their usage of gasoline. Even if you aren’t terribly concerned about your ecological footprint, the fact of the matter is that electricity prices are so low in many places that an electric vehicle is cheaper to operate than one which burns gas at $2.50+ USD a gallon.

Another advantage, at least in theory, is reduced overal maintenance cost. While a modern EV will of course be packed with sensors and complex onboard computer systems, the same could be said for nearly any internal combustion engine (ICE) car that rolled off the lot in the last decade as well. But mechanically, there’s a lot less that can go wrong on an EV. For the owner of an electric car, the days of oil changes, fouled spark plugs, and the looming threat of a blown head gasket are all in the rear-view mirror.

Unfortunately, it seems the rise of high-tech EVs is also ushering in a new era of unexpected failures and maintenance woes. Case in point, some owners of older model Teslas are finding they’re at risk of being stranded on the side of the road by a failure most of us would more likely associate with losing some documents or photos: a disk read error.

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When Life Gives You Lemons, Make A Rube Goldberg Machine

October 17, 2019 by Sharon Lin 10 Comments

When life gives you lemons, you make lemonade. At least that’s what the [Sprice Machines] thought when they decided to turn a house into the set of a 9-minute long Rube Goldberg machine to make lemonade. (Video embedded below.) The complex chain reactions runs across multiple rooms, using everyday objects like brooms and even a vibrating smartphone to transfer energy across the complex contraption.

While the team professionally builds Rube Goldberg machines for clients, the Lemonade Machine looks surprisingly organic, like something a family might decide to do for fun over a long weekend (although there area few moments that make you question just how they were able to perfectly time every sequence in the chain reaction). Even though the actual lemonade making only takes up a small fraction of the machine, watching marble runs, weights dashing across a clothesline, and random household items repurposed into energy transfer mechanisms is really entertaining.

The [Sprice Machines] have been making Rube Goldberg machines for quite some time, posting the videos of their final runs on YouTube. Other builders for the Lemonade Machine included [Hevesh5], [DrComplicated], [DoodleChaos], [TheInvention11], [5MadMovieMakers], and [SmileyPeaceFun].

If you’re into Rube Goldberg machines, check out some of the other awesome projects that we’ve featured over the years on the blog.

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Long Live Jibo, Our Adorable Robot Companion

October 17, 2019 by Sharon Lin 11 Comments

Jibo, the adorable robot made by Jibo, Inc., was getting phased out, but that didn’t stop [Guilherme Martins] from using his robot companion for one last hack.

When he found out that the company would be terminating production of new Jibos and shutting down their servers, he wanted to replace the brain of the robot so that it would continue to live on even after all of its software had become deprecated. By the time the project started, the SDK downloads had already been removed the from developer’s site, so they looked at other options for controlling Jibo.

The first challenge was to not break the form factor in order to disassemble Jibo. They only managed to remove the battery from the bottom, realizing that the glass frame held the brain room. From within the robot, they were able to find the endless rotation joint for the head and the heart of the electronics. Jibo uses a DC motor, encoder, and IR sensor at each of three distinct levels to detect reference points.

They decided to use Phidgets modules to interface with these devices. While the DC motor controller handles 2A and has an encoder port, the Phidgets are able to provide software with the encoder and PID built-in. The 4x Digital Input Module was used for detecting the IR switch and connecting the modules to the computer.

[Martins] decided to use LattePanda, a hackable Windows 10 development board, for the brain of the new Jibo. The board was luckily able to fit inside the compartment for Jibo, but since it requires more power the unit is powered with 12V regulated to 5V in order to have less current passing through the wires. The DC motors, meanwhile, run at 12V and the IR switches and encoders at 5V.

A program developed in Unity3D plays the eye animations, and a C# program interfaces with the Phidgets. The final configuration was to fit Jibo onto a robotic arm to augment its behaviors. We previously wrote about Toppi, the robotic arm artist, that was used as the base for Jibo’s new home.

You can check out the result in the video below.

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