Raspberry Pi Spies On Your Front Door

August 6, 2014 by Bryan Cockfield 15 Comments

doorbell pictures

One of [Sander]’s first projects with a Raspberry Pi was to get it to send messages to his iPhone. From there he decided to take it a step further and wire the tiny computer up to his doorbell, creating a system that can send push messages to his phone whenever someone is at the front door.

[Sander]’s doorbell is wireless, and he decided to keep all of its original functionality. All it took to signal the Pi was a simple circuit tied to the doorbell’s status LED which turns off whenever the doorbell is pushed.

The Raspberry Pi runs a python program that handles the GPIO pin which is wired to the doorbell. When the doorbell is pushed, the program processes and sends the push notification while taking pictures of the visitor with an attached webcam. The pictures are included in the message so [Sander] can see who is at the front door. The code for the project is included on his project page.

This project rang a bell for us since we’ve seen projects using a Raspberry Pi and push notifications. None of them so far have included a webcam or utilized an existing wireless doorbell though, and this is a great step forward!

Unlocking A Door With A Phone – Easy As Pi!

August 5, 2014 by Matt Terndrup 11 Comments

doorman2

[Ian] has created a way for his office colleagues to get inside the door, even if they have forgotten their keys. This office automation, Raspberry Pi set up is appropriately named the ‘Doorman’ and provided an alternative method of unlocking the entry system.

His solution tapped into the existing security circuit, which is closed by a simple relay, which is connected to the main piece of hardware; a Raspberry Pi. On one side of the Pi is the GPIO pins that allow control access while the other side links to the internet. The company’s internal system is responsible for authenticating users, issuing keys and processing access requests. A mobile client, aka a smartphone, can request a set of keys from the Doorman.

[Ian] used the Golgi SDK to speed up the development of the in-house app. With the wires in place, the Doorman has become a great success, and now forgotten keys are a thing of the past. And even though staff members no longer need to buzz into the office interrupting their co-workers, the development team has plans to beef up their office automation system. Already other innovations are being created to be integrated in with the Doorman.

Now all that’s left is to show a video demonstration of the Doorman, which can be seen after the break:

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Raspi Ambilight Integrated In A 19″ Rack Packs Lots Of Peripherals

August 2, 2014 by Mathieu Stephan 6 Comments

Ambilight systems create light effects around your monitor that correspond to the video content you’re playing. [Sébastien] just build his (French translated to English, original here) and embedded all the elements in a 19 inch rack he bought from Farnell.

As most ambilight systems we’ve covered over the years the HDMI signal is first split in two, one being sent to his monitor while the other is converted into a S-Video signal. The latter is then captured with a STK1160 stick connected to a Raspberry Pi. A python script using the OpenCV library is in charge of extracting the frames pixels and figuring out what colors should be sent to the SPI connected LPD8806 LEDs. A nice web interface also allows to drive the LEDs from any platform connected to his local network. Finally, a standard HD44780 LCD and an infrared receiver are connected to the raspberry, allowing [Sébastien] to control and monitor his platform. Funny thing: he also had to use two relays to power cycle his HDMI splitter and converter as they often crash. You can check out a demonstration video from a previous revision after the break.

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A Real Raspberry Pi Clone (Not ‘Inspired By’)

July 30, 2014 by Brian Benchoff 63 Comments

odroid A few years ago, Broadcom had a pretty nice chip – the BCM2835 – that could do 1080 video, had fairly powerful graphics performance, run a *nix at a good click, and was fairly cheap. A Broadcom employee thought, “why don’t we build an educational computer with this” and the Raspberry Pi was born. Since then, Broadcom has kept that chip to themselves, funneling all of them into what has become a very vibrant platform for education, tinkering, and any other project that could use a small Linux board. Recently, Broadcom has started to sell the BCM2835 to anyone who has the cash and from the looks of it, real Raspberry Pi clones are starting to make their way into the marketplace.

Other Raspberry Pi clone boards out there like the Banana Pi and the HummingBoard don’t use the same BCM2835 found in the Raspi and the new Odroid. The new board also has the same 26 pin GPIO expansion socket, and runs the same binaries as the Raspberry P;. It is a clone in every sense, with a slightly different form factor geared towards very tiny, portable, and battery-powered use cases.

Unlike the official Raspberry Pi Compute Module, the Odroid isn’t meant to be used as a system on module, shoved into any product that needs a fast-ish ARM core without needing engineers to actually design a circuit with an ARM. The Odroid is a cut-down, extremely minimalist version of the Raspi, perfect for any project where space is at a premium.

There are a few interesting features included on the Odroid: there’s an on-board battery connector, a real-time clock on the board, and more of the BCM2835 GPIOs are exposed (although not the same ones as the upgraded RPi Model B+). There’s no Ethernet, but odds are if you’re building something that’s battery-powered, you won’t need that anyway.

As far as price goes, you can pick one of these Odroids up for $30 USD, with $9 shipping from South Korea. That’s pretty comparable to the price of a real Raspberry Pi, but if the features in the Odroid are worth it to you, it might be a worthwhile clone.

ASTROGUN Is Like Asteroids On Steroids

July 27, 2014 by Rick Osgood 50 Comments

Astrogun

As the Jerusalem mini Makerfaire approached, [Avishay] had to come up with something to build. His final project is something he calls ASTROGUN. The ASTROGUN is a sort of augmented reality game that has the player attempting to blast quickly approaching asteroids before being hit.

It’s definitely reminiscent of the arcade classic, Asteroids. The primary difference is that the player has no space ship and does not move through space. Instead, the player has a first person view and can rotate 360 degrees and look up and down. The radar screen in the corner will give you a rough idea of where the asteroids are coming from. Then it’s up to you to actually locate them and blast them into oblivion before they destroy you.

The game is built around a Raspberry Pi computer. This acts as the brains of the operation. The Pi interfaces with an MPU-9150 inertial measurement unit (IMU). You commonly see IMU’s used in drones to help them keep their orientation. In this case, [Avishay] is using it to track the motion and orientation of the blaster. He claims nine degrees of freedom with this setup.

The Pi generates the graphics and sends the output to a small, high-brightness LCD screen. The screen is mounted perpendicular to the player’s view so the screen is facing “up”. There is a small piece of beam splitting glass mounted above the display at approximately a 45 degree angle. This is a special kind of glass that is partially reflective and partially translucent. The result is that the player sees the real-world background coming through the glass, with the digital graphics overlaid on top of that. It’s similar to some heads-up display technologies.

All of the electronics fit either inside or mounted around a toy gun. The display system was attached with a custom-made fiberglass mount. The code appears to be available via Github. Be sure to watch the video of the system in action below. Continue reading “ASTROGUN Is Like Asteroids On Steroids” →

Adding GPIOs To The Raspberry Pi With The Camera Interface

July 24, 2014 by Brian Benchoff 9 Comments

GPIOs

The Raspberry Pi Model B+ was just released, and now everyone who picks one of those up has a few more GPIO pins to play around with. For the millions of people with the two-year-old version of the Pi, we’re still stuck with the same old, same old: 17 GPIOs on the big header, and that’s about it as far as toggling pins goes.

The Broadcom SoC on the Pi has far more GPIO pins than are broken out on the large header, and a few of those go to the CSI camera interface. These GPIOs can be broken out with a few flat cables (Portuguese, Google Translatrix), giving you four more GPIOs, and this technique can also be used with the new, expanded Model B+.

The CSI camera connector has two I²C lines that go directly to the camera, controllable in Linux as GPIO0 and GPIO1. There are two more GPIO connectors on the CSI connector controllable as GPIO5 and GPIO21. By carefully slicing and soldering wires to a flat cable, these GPIO lines can be broken out onto a breadboard.

There’s a video below demonstrating these GPIO lines being used to control a few LEDs. Of course, anything that is possible with a normal Raspi GPIO is possible with the CSI connector GPIO lines.

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Smart Hat Puts Your Head In The Game

July 22, 2014 by Will Sweatman 8 Comments

man wearing a diy head mounted display

[Arvind] has dropped his hat in the game of head mounted displays. With Google Glass pushing $1,500, it’s only natural for hackers to make a cheaper alternative. [Avind’s] $80 version might not be pretty, but it gets the job done.

Using a Raspberry Pi loaded with speech recognition software, a webcam, 2.5 inch LCD display and a handful of other parts, [Arvind’s] hat mounted display allows him to view email, Google Maps, videos or just about anything he wants.

An aspheric loupe magnifier lens lets him see the display even though it sits around 5cm from his eye. No outside light is allowed in. Only the guts of the webcam were used to give him the video and microphone. We’ve seen other head mounted displays before, and this one adds to the growing collection. Be sure to check out [Arvinds] site for a tutorial on how to build your own, and catch a video of it in action after the break.

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