Pressure Gauge Used to Monitor Internet Usage

Steam Gauge Keeps Track Of Your Internet Usage

There’s a certain appeal to analog gauges in a vastly digital world. [Ed Konowal] is a Network Operations Supervisor for a school district in Florida — part of his job is to ensure a stable and fast internet connection, so he decided to make an internet usage gauge for his office.

What we really like about this hack is the fact that [Ed] had no idea how to do it. It’s a simple enough idea, right? Google was his friend and Ed started learning about all kinds of things. Raspberry Pi’s and Arduinos, wireless receiver/transmitters, servos and steppers, Python…

After quite a bit of trial and error, [Ed] eventually settled on a wired design which uses a Raspberry Pi running a Python program to poll the internet bandwidth, which in turn calculates the servo position for the dial and sends that number to the Arduino to move it into position. This repeats every 10 seconds. Pretty cool!

Kind of reminds us of this project to make custom gauges using a stepper motor breakout board!

[Thank Justin!]

Faucet Add-On Attempts To Save Water By Changing Colors

FU8WVVBHW6T8E8I.LARGE

This augmented water device was rapidly developed during an H2O hackathon in Lausanne, Switzerland. It was built by a software engineer code-named [tamberg]. His creation contained an Arduino Uno, a strip of NeoPixels, a liquid flow sensor, and a tiny lithium-ion battery attached to a cut medical tube that was re-purposed for monitoring water use.

From the looks of it, this project addressed a specific problem and went on to solve it. The initial prototype showed a quick and dirty way to monitor precious water that is literally being flushed down the drain.

To see how the device was made, click the first link posted above for a set of Instructables. Code for the device can be found on [tamberg]’s bitbucket account. A demo video of the device being tested on a sink can be seen after the break.

Continue reading “Faucet Add-On Attempts To Save Water By Changing Colors”

A MIPI DSI Display Shield/HDMI Adapter

MIPI DSI shield

[Tomasz] tipped us about the well documented MIPI DSI Display Shield / HDMI Adapter he put on hackaday.io. The Display Serial Interface (DSI) is a high speed packet-based interface for delivering video data to recent LCD/OLED displays. It uses several differential data lanes which frequencies may reach 1 GHz depending on the resolution and frame rate required.

The board explained in the above diagram therefore allows any HDMI content to be played on the DSI-enabled scrap displays you may have lying around. It includes a 32MB DDR memory which serves as a frame buffer, so your “slow” Arduino platform may have enough time to upload the picture you want to display.

The CP2103 does the USB to UART conversion, allowing your computer to configure the display adapter internal settings. The platform is based around the XC6SLX9 Spartan-6 FPGA and all the source code may be downloaded from the official GitHub repository, along with the schematics and gerbers. After the break we’ve embedded a demonstration video in which a Raspi drives an iPhone 4 LCD.

Continue reading “A MIPI DSI Display Shield/HDMI Adapter”

Retrotechtacular: Forces Acting On An Airfoil

floating film title We’ve probably all experimented with a very clear demonstration of the basic principles of lift: if you’re riding in a car and you put your flattened hand out the window at different angles, your hand will rise and fall like an airplane’s wing, or airfoil. This week’s Retrotechtacular explains exactly how flight is possible through the principles of lift and drag. It’s an Army training documentary from 1941 titled “Aerodynamics: Forces Acting on an Air Foil“.

What is an airfoil? Contextually speaking, it’s the shape of an airplane’s wing. In the face of pressure differences acting upon their surfaces, airfoils produce a useful aerodynamic reaction, such as the lift that makes flight possible. As the film explains, the ideas of lift and drag are measured against the yardstick of relative wind. The force of this wind on the airfoil changes according to the acute angle formed between the airfoil and the direction of the air flow acting upon it. As you may already know, lift is measured at right angles to the relative wind, and drag occurs parallel to it. Lift is opposed by the weight of the foil, and drag by tension.

wind tunnel testing

Airfoils come in several types of thicknesses and curvatures, and the film shows how a chord is derived from each shape. These chords are used to measure and describe the angle of attack in relation to the relative wind.

The forces that act upon an airfoil are measured in wind tunnels which provide straight and predictable airflow. A model airplane is supported by wires that lead to scales. These scales measure drag as well as front and rear lift.

In experimenting with angles of attack, lift and drag increase toward what is known as the stalling angle. After this point, lift decreases abruptly, and drag takes over. Lift and drag are proportional to the area of the wing, the relative wind velocity squared, and the air density. When a plane is in the air, drag is a retarding force that equals the thrust of the craft, or the propelling force.

monometer tubesAirfoil models are also unit tested in wind tunnels. They are built with small tubes running along many points of the foil that sit just under the surface. The tubes leave the model at a single point and are connected to a bank of manometer tubes. These tubes compare the pressures acting on the airfoil model to the reference point of atmospheric pressure. The different liquid levels in the manometer tubes give clear proof of the pressure values along the airfoil. These levels are photographed and mapped to a pressure curve. Now, a diagram can be made to show the positive and negative pressures relative to the angle of attack.

In closing, we are shown the effects of a dive on lift as an aircraft approaches and reaches terminal velocity, and that lift is attained again by pulling slowly out of the dive. Remember that the next time you fly your hand-plane out the window.

Continue reading “Retrotechtacular: Forces Acting On An Airfoil”

Open Source GPU Released

GPLGPU

Nearly a year ago, an extremely interesting project hit Kickstarter: an open source GPU, written for an FPGA. For reasons that are obvious in retrospect, the GPL-GPU Kickstarter was not funded, but that doesn’t mean these developers don’t believe in what they’re doing. The first version of this open source graphics processor has now been released, giving anyone with an interest a look at what a late-90s era GPU looks like on the inside, If you’re cool enough, there’s also enough supporting documentation to build your own.

A quick note for the PC Master Race: this thing might run Quake eventually. It’s not a powerhouse. That said, [Bunnie] had a hard time finding an open source GPU for the Novena laptop, and the drivers for the VideoCore IV in the Raspi have only recently been open sourced. A completely open GPU simply doesn’t exist, and short of a few very, very limited thesis projects there hasn’t been anything like this before.

Right now, the GPL-GPU has 3D graphics acceleration working with VGA on a PCI bus. The plan is to update this late-90s setup to interfaces that make a little more sense, and add DVI and HDMI output. Not bad for a failed Kickstarter, right?

Developed On Hackaday: Beta Testers And Automated Testing

Mooltipass with Holder

At Hackaday we believe that your encrypted vault containing your credentials shouldn’t be on a device running several (untrusted) applications at the same time. This is why many contributors and beta testers from all over the globe are currently working on an offline password keeper, aka the Mooltipass.

Today we’re more than happy to report that all of our 20 beta testers started actively testing our device as they received the v0.1 hex file from the development team. Some of them had actually already started a few days before, as they didn’t mind compiling our source files located on our github repository and using our graphics generation tools. We are therefore expecting (hopefully not) many bug reports and ways to improve our device. To automatize website compatibility testing, our beta tester [Erik] even developed a java based tool that will automatically report non-working pages found inside a user generated list. You may head here to watch a demonstration video.

The Most Basic BASIC Computer

AVR microcontrollers can do pretty much anything nowadays. Blinking LEDs, handling sensor inputs, engine control modules, and now, thanks to [Dan], a small single chip BASIC computer with only ten parts (and four of them are capacitors).

[Dan]’s homebrew computer has it all. The ATmega 1284P microcontroller outputs a composite video signal and handles inputs from a PS/2 keyboard. The microcontroller runs at 16 MHz, has 7 kB of memory for programs, and can use a separate EEPROM to store data. It also has an array of GPIO pins for interacting with the physical world.

For software, the microcontroller runs a version of BASIC called Tiny BASIC plus, which is a stripped-down language that can fit in 3 kB of memory. This is crucial if you’re in the 1970s or if you’re programming on an AVR microcontroller in the 21st century.

We’ve seen other Arduinos and AVR-type microcontrollers that can run BASIC, but this one has a great form factor and clean look. It’s also a great way to get familiar with homebrew computing and the BASIC programming language!