Creating a multimedia elevator ride

[Ben Peoples] works in theatrical electronics. Sounds like fun, and here’s an example of the kind of stuff he does. We’re not sure what event this installation was used for, but if the elevator ride needed something flashy just think of what the party room must have looked like. These HDTV screens on the ceiling of the elevator play different clips when the elevator is moving up or down. The challenge for [Ben] was to find a way to make it work without tapping into the elevator electronics or requiring any button presses.

The first attempt at sensing the elevator’s travel was done with an accelerometer. The problem with this approach is that an accelerometer only senses change in acceleration and this method proved to be fairly error prone. [Ben] switched over to a reflective sensor which performed quite well. Since most of these sensors will only work within about an eighth of an inch he ended up building his own with a LDR and a couple of amber LEDs.

[via Reddit]

Projector calibration on uneven surfaces made easy

projector-calibrator

If you are thinking of building your own flight/racing sim setup at home, you might want to check this out. [Alex] from the Garoa Hackerspace in Säo Paulo, Brazil put together a slick setup that makes projector image calibration a breeze.

When building a wraparound screen for such a simulator, you are likely to run into problems with both overlapping images and distortion from the curved projection. There are projectors that can easily adjust themselves to work in this sort of setup, but they are often very expensive, so [Alex] thought he would build a solution himself.

After studying a paper written by [Johnny Chung Lee] in 2004, he built a prototype display calibrator last year that used similar, though slightly tweaked methods to get the job done. This time around, [Alex] has improved his calibrator, making the process more precise and a bit quicker.

Light sensors and an Arduino are attached to the back of the projection medium, and a large broad scan of the screen is performed by the projector. His code then triggers an additional sweep of each corner to better estimate the exact edges of his projection surface. Since the video is tweaked in software rather than relying on the projector hardware to handle the task, the result is cheap and very accurate.

Don’t take our word for it though, check out [Alex’s] video demonstration below to see his calibrator in action.

[Read more...]

Hackaday Links: December 16, 2011

Free-form Christmas ornament

Here’s [Rob]‘s free form circuit that’s a Christmas ornament for geeks. It looks great, but sadly isn’t powered through a Christmas light strand. It’s just as cool as the skeletal Arduino we saw.

Prototyping with flowers

Well this is interesting: protoboard that’s specifically made to make SMD soldering easier. The guys at elecfreaks went through a lot of design iterations to make sure it works.

We’ll call it Buzz Beer

The days are getting longer and cabin fever will soon set in. Why not brew beer in your coffee maker? It’s an oldie but a goodie.

Christmas oscilloscope

With just an ATtiny and a little bit of  futzing around changing the coefficients of a partial differential equation, you too can have your very own oscilloscope Christmas tree. Don’t worry though, there are instructions on how to implement it with an Arduino as well. HaD’s own [Kevin] might be the one to beat, though.

So what exactly does a grip do?

You know what your home movies need? A camera crane, of course. You’ll be able to get some neat panning action going on, and maybe some shots you couldn’t do otherwise. Want a demo? Ok, here’s a guy on a unicycle.

Video display from RGB strips makes it seem so easy

[Fabien] wrote in to share a link to this RGB video display which he made. He’s got some pretty cool routines that make it more functional than you would think, but first we want to comment on the construction. He used an RGB strip, which makes this look like an incredibly simple build. The strip has a data and power bus running the length of it. You can it into smaller segments, then just solder jumper wires to reconnect the buses. That’s exactly what he did here, making it what must be the fastest method of putting together a display of this size (16×10 pixels).

It’s driven by a Netduino which easily addresses the LPD8806 drivers responsible for the LEDs. It gets input from a computer via Xbee, making it easy to include data from the net, or to push visualizations. The video after the break shows a [Van Gogh] self-portrait. Since 160 pixel resolution wouldn’t do it justice, the visualization software shows a zoomed in portion of the painting which is constantly panning to let you see the entire work. It’s a fabulous effect.

[Read more...]

Video: Interrupts on the ATmega328p

This week, we are bringing you the final video in our series where [Jack] uses the 3pi robot as a fancy development board for the ATmega328p processor. Today’s video deals with interrupts. If you have been wanting to have your programs do more than one thing simultaneously, interrupts are the solution. [Jack] discusses various ways that you can use interrupts in your programs and then shows how he created a interrupt routine that drives the 3pi’s beeper. He also shows the routines that enable, disable, and control the interrupt.

Since this is the last post for this series of videos, we are posting the code used for all of the previous videos. Click here to grab a copy.

For our next series of videos, we are going to attempt something more challenging so most likely we will be taking a couple of weeks off to do some development before presenting it here. Stay tuned folks, we’ll be back.

Video is after the break…

In case you missed any of the previous videos, check out these links:

Part 1: Setting up the development environment
Part 2: Basic I/O
Part 3: Pulse Width Modulation
Part 4: Analog to Digital conversion
Part 5: Working with the 3pi’s line sensors

[Read more...]

There’s a lot packed into this BeagleBoard controlled rover

That black box is hiding all kinds of goodies that make this rover a hacking playground. [Andrey] built the device around a BeagleBoard, which offers the processing power and modules that he needed to make the rest of it work.

The control unit shrinks the pilot down to the rover’s size, using a cockpit that has a steering wheel and other controls, and a monitor playing the stream from the camera on the front of the bot. It has a WiFi adapter which allows control via the Internet. The camera, which can be rotated thanks to its servo mounting, feeds the video to the BeagleBoard where it is compressed using the h264 codec (more about that and the cockpit here) to lighten the streaming load. You’ll also find an ultrasonic rangefinder on the front for obstacle avoidance, and a magnetic compass for orientation information. Finally, a GPS bolsters that data, allowing you to plot your adventures on the map.

It’s great, but it will cost you. Material estimates are North of five hundred Euros!

Big Head costume would make Max Headroom jealous

big-head-halloween

[Dan Rosenfeld] does a lot of thinking in his spare time, and one thing he returns to pretty often is videoconferencing. He’s often wondered why it hasn’t caught on enough to become a ubiquitous piece of technology, and his examination of the topic in regards to eye contact and spatial awareness inspired him to create a very unique Halloween costume.

His “Big Head” costume consists of a front-mounted 24” LCD panel that displays the wearer’s face in real time. Inside the large headpiece [Dan] installed a microphone, another LCD screen, a half silvered mirror, and a video camera – not to mention all of the power-related goodies required to keep it running. While the main LCD displays his face, the internal monitor is fed by an externally mounted camera that shows him everything going on outside the box. This image is reflected off the half silvered mirror, allowing him to gaze directly at the camera, while also seeing what’s going on in front of him.

As you can see in the video below, the effect is pretty cool, and devoid of the ‘disconnected’ look most people have when talking to others via a camera and computer screen.

[Read more...]

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