raspberry pi

1709 Articles

Hackaday Prize Entry: Detecting New Meteor Showers

August 5, 2015 by 5 Comments

Go out to a field on a dark night, far away from city lights, and you might just see a shooting star. A single meteor is just a tiny fraction of all the space dust that hits our atmosphere every day; most of it goes completely unnoticed. To get a better idea of where these meteoroids come from, [Dario] and [Denis] have come up with a network of meteor-detecting ground stations to search for these extraterrestrial visitors and make it possible to retrieve the largest of these fallen stars.

This project started at the Croatian Meteor Network, a team with about two dozen surveillance cameras pointed skyward as an unblinking eye, looking for meteoroids entering the Earth’s atmosphere over the Balkans and the Adriatic sea. When two cameras detect a meteor, the path it came from – and its orbit around the Sun – can be computed. The team has already found a possible new meteor shower (PDF) that is active from late August to the middle of September.

With hundreds of cameras scattered around the globe, it’s possible to triangulate the position of these meteors and their orbit around the Sun, just like what was done with the innumerable Russian dash cams after the Chelyabinsk meteor. It’s a great project, and also one that requires a lot of computer image processing – a favorite around these parts.

The 2015 Hackaday Prize is sponsored by:

Polarization Camera Views The Invisible

July 28, 2015 by 55 Comments

Light polarization is an interesting phenomenon that is extremely useful in many situations… but human eyes are blind to detecting any polarization. Luckily, [David] has built a polarization-sensitive camera using a Raspberry Pi and a few off-the-shelf components that allows anyone to view polarization. [David] lists the applications as:

A polarimetric imager to detect invisible pollutants, locate landmines, identify cancerous tissues, and maybe even observe cloaked UFOs!

The build uses a standard Raspberry Pi 2 and a 5 megapixel camera which sits behind a software-controlled electro-optic polarization modulator that was scavenged from an auto-darkening welding mask. The mask is essentially a specialized LCD screen, which is easily electronically controlled. [David] whipped up some scripts on the Pi that control the screen, which is how the camera is able to view various polarizations of light. Since the polarization modulator is software-controlled, light from essentially any angle can be analyzed in any way via the computer.

There is a huge amount of information about this project on the project site, as well as on the project’s official blog. There have been other projects that use polarized light for specific applications, but this is the first we’ve seen of a software-controlled polarizing camera intended for general use that could be made by pretty much anyone.

The 2015 Hackaday Prize is sponsored by:

3D Mouse Drives Robot Arm

July 28, 2015 by 17 Comments

You’ve built the perfect robotic arm. How do you drive it? If you are [angrymop] you interface a 3D mouse from 3DConnexion via a few microcontroller boards. The Spacenavigator mouse is a staple anywhere professional CAD people are working, and it looks like it is a natural fit for a robot arm.

According to [angrymop], the Raspberry Pi can read the mouse’s commands via /dev/hidraw (that’s the raw human interface device). Each motion generates two lines of output. Each line has a unique identifying byte and values corresponding to the axis positions.

The Raspberry Pi then uses an SPI interface to talk to an ARM microcontroller and that drives the servos. The arm (the robot arm, not the processor) itself is well done, made from Lego Technic parts and common RC servos. Not that this is the most amazing thing we’ve ever seen built from Technic, but it is still pretty impressive.

You have to wonder if other 3D controllers might be useful for controlling robot arms or how the Spacenavigator would do controlling a bigger, more capable arm. Then again, maybe this arm would be the right size to build something inspired by Escher.

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DDR-ing A Simon Game With A Raspberry Pi

July 24, 2015 by 8 Comments

Since 1998 we’ve been privileged to partake in an arcade game known as Dance Dance Revolution, but before that, way back in the 70’s, was the Simon game. It’s essentially a memory game that asks the player to remember a series of lights and sounds. [Uberdam] decided to get the best of both worlds and mixed the two together creating this giant foot controlled Simon game. (English translation.)

The wood platform that serves as the base of the project was fitted with four capacitive sensors, each one representing a “color” on the Simon game. When a player stomps on a color, a capacitive sensor sends a signal to a relay which in turn notifies the Raspberry Pi brain of the input. The Pi also takes care of showing the player the sequence of colored squares that must be stepped on, and keeps track of a player’s progress on a projector.

This is a pretty good way of showing how a small, tiny computer like the Raspberry Pi can have applications in niche environments while also being a pretty fun game. We all remember Simon as being frustrating, and we can only imagine how jumping around on a wooden box would make it even more exciting. Now, who can build a robot that can beat this version of Simon?

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Another IoT Platform In The (Blue)Mix

July 23, 2015 by 19 Comments

Many major companies (Intel, Oracle, Atmel, and IBM, for example) are competing to be the standard interconnect fabric for the Internet of Things. As a developer, it is hard to cut through the marketing hype and decide which platform is the best for you and your application. Luckily, there’s a plethora of projects on the web that showcase these frameworks. These project sites are an easy way to evaluate the strengths and weaknesses of IoT frameworks in practical applications without having to develop prototypes yourself.

[diyhacking], for example, posted a demo of using IBM’s Bluemix along with a Raspberry Pi, to do some simple home automation tasks. The project hardware is modest, using a PIR motion sensor and a relay to control an AC load. However, that’s good because it lets you focus on the Bluemix tools. The example client and server software is less than 200 lines of Python.

Bluemix looks like it has good integration with the Raspberry Pi and features a simulator so you can work without real hardware for development. Bluemix does offer a free plan (with limits), but the fee options may be a turn off to some IoT hackers.

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remote control

Hacking Amazon Echo Through Its Remote

July 18, 2015 by 27 Comments

This one’s crazy… literally one electronic device is talking to another. In spoken English. And it works.

We’ve covered several hacks for the Amazon Echo, but some might be surprised to learn that there is another piece of interesting hardware that comes along with it – a remote control. Wire in a Raspberry Pi to it, and you’ve given yourself a way to automate control of the Echo without ever taking the Echo itself apart. [Gamaral] did just this and gave his Echo some significantly enhanced capabilities.

He started off by identifying the power rails of the remote. Then he wires in a 3.3v voltage regulator and uses a 100 ohm resistor as a voltage divider to bring it down to the 1.8 volt logic level used by the Echo remote. A single wire runs from the Raspi GPIO to one of the tactile switches on the controller.

For software, the Raspi is running RPi buildroot with Espeak and a cron scheduler compiled in. This allows him to send commands to the Echo which makes it say just about anything he wants. But any voice commands accepted by the Echo should work. If you want to go outside of those boundaries check out the method of spoofing WeMo devices we saw the other day.

Be sure to check out the [gamaral’s] entertaining video below to see the hack in action.

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Arduino And IR Remote Turn Off Raspberry Pi

July 18, 2015 by 18 Comments

With all of the cool features on the Raspberry Pi, it is somewhat notable that it lacks a power button. In a simple setup, the only way to cut power to the tiny computer is to physically remove the power cord. [Dalton63841] found that this was below his wife’s tolerance level for electronics, and built a simple remote control for his Raspberry Pi.

[Dalton63841] started this project by trying to use the UART TX pin, but this turned out to be a dead-end. He decided instead to use an Arduino to monitor the 3.3V power rail on the Pi. When the Pi is shut down in software, the Arduino can sense that the Pi isn’t on any more and disconnect the power. The remote control is used to turn the Pi on. The Arduino reads the IR code from a remote and simply powers up the Pi. This is a very simple and elegant solution that requires absolutely no software to be installed on the Raspberry Pi.

We know that this isn’t the most technically complex project we’ve ever featured, but it is a good beginner project for anyone just getting started with a Pi, Arduino, or using IR. Plus, this could be the perfect thing to pair up with a battery-backup Raspberry Pi shutdown device that allows it to power itself down in a controlled way when a power outage is sensed.