accelerometer

181 Articles

Using A Cheap Accelerometer With Arduino Comes With A Catch

February 10, 2012 by 22 Comments

[Boris Landoni] put together a guide to using an inexpensive 3-axis accelerometer with Arduino. The chip that he chose for the exercise is an MMA7455L made by Freescale. It’s got a lot of nice features packed into it, using hardware to do some of the things you’d need software for with other chips like reporting in which direction the chip is moving, detecting when movement has stopped, and few others. It’s an I2C device, so the examples he provides will be super simple to port to your uC of choice.

But as the title says, there’s a catch. The chip is extremely versatile and you can get your hands on one for under $2. But check out the size of it. That’s a DFN (dual flat no-lead) package which means there are no pins on it. The package has solder contacts on the bottom which do not protrude out the sides. If you want to do some at-home prototyping with the chip you’ll need a hot air pencil or reflow gear as hand soldering is unlikely to be successful. We’re not saying it’s impossible, but it is quite tricky.

Of course, if you’ve got the secret to getting this done with a quality soldering iron we’d like to hear about it.

Ball-in-maze Game Shows Creativity And Classic 8-bit Sound

January 19, 2012 by 4 Comments

[M. Eric Carr] built this a long time ago as his Senior Project for EET480. It’s an electronic version of the ball-in-maze game. We’ve embedded this video after the break for your convenience.

The game has just one input; an accelerometer. If you’re having trouble visualizing the game, it works the same as this Android-based version, but replaces the physical maze and marble with a virtual maze on the graphic LCD screen. This has huge implications. Instead of just recreating the maze on the screen, [Eric] designed a multi-screen world, complete with warp blocks, which adds difficulty to  finding a solution. It also means that multiple different mazes can be played if you get tired of playing the same level.

This game also features music. A separate PIC microcontroller uses PWM to push out the 8-bit sound heard in the video. From the YouTube comments we learned that [Eric] didn’t write the music himself, but we still appreciate the playback quality he achieves with his hardware.

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POV Bauble Uses DIY Accelerometer To Sync The Image

November 16, 2011 by 6 Comments

So we saw this tip come in and thought–oh, another POV device. We watched the video (embedded after the break), took a sip of coffee, then almost sprayed the beverage all over the computer when we realized that this uses a diy sensor to synchronize the POV image.

[Ch00f] came up with the idea for the sensor after seeing a similar implementation on a commercial POV toy. Instead of using a proper accelerometer to sense the motion, the toy uses a plastic bead in a channel. When you move the body of the toy the bead rolls to one end or the other, covering or exposing a reflective sensor.

A similar sensor is used here. A drinking straw servers as the channel, with a paper-covered nylon screw as the bead. [Ch00f] cut a window in the bottom of the straw for his reflective sensor, then sealed each end with a wad of paper.

This method works, but not as well as he had hoped. It seems the refresh rate and timing of the particular sensor he’s using is rather poor. If it were replaced with one that is simply and IR LED and phototransistor (like the sensors from [Jack’s] last video) he thinks it would work a lot better.

via Buildlounge.

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Ball Of Dub Has Lots Of Wub

October 29, 2011 by 23 Comments

[Lizzie] from LustLab sent in her Ball of Dub that turns a few accelerometer and a digital audio workstation and turns everything into an aural experience of wubs and dubs. The Ball of Dub can turn just about anything into dubstep, and does so with a fairly interesting user interface.

There isn’t a build log for the Ball of Dub, but  the folks at LustLab did send in a basic overview of her project. Inside the ball, there’s a Razor IMU from Sparkfun that is attached to the ever-popular XBee wireless transceiver. A tiny program on an Arduino calibrates the gyroscope and accelerometer and sends that data to the DAW at 50Hz.

The host computer is running Renoise, a very popular tracker that can accept MIDI and OSC input. A Processing app parses the ball spin, free fall and impact, averages them over a period of time, and pipes that into the OSC input of Renoise. In [Lizzie]’s video, the ball spin is sent to a low-pass filter on the baseline track, and the average impact is applied to the vocal track.

This isn’t the first time we’ve seen some fairly strange ways to modulate wub; we saw real instruments covering Skrillex earlier this month. The Ball of Dub wins in the simplicity department, though.

Wii Remote Controling The Vehicle You’re Riding In

October 29, 2011 by 20 Comments

Make sure your health insurance premiums are all paid up; if you decide to replicate this project you may need it. [Corey], [Kris], and [Jess] built their own go cart which is controlled with a Wii remote. The website has a poor navigation scheme, but if you hover over the horizontal menu bar you can get quite a bit of information about the build.

The cart has two motors which use a chain to drive each of the rear wheels. A pair of H-bridge controllers let the Arduino interface with them. It’s also has a Bluetooth module that makes it a snap to pull accelerometer data from the Wii remote. The front end looks like it uses rack and pinion steering, but you won’t find a pinion or a steering column. Instead, a linear actuator is mounted parallel to the rack, moving it back and forth at the command of the Arduino.

We can’t help but think back to silent movies where the steering wheel comes loose in the middle of a car chase. See if you get the same image while watching the demo after the break. This doesn’t seem quite as dangerous as adding remote control to a full-sized automobile, but we’ve played MarioKart Wii before and know how lousy the accelerator performance can be. Hopefully the firmware kills the motors if the batteries in the controller die.

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Panoramic Ball Camera; Toss To Snap A Picture

October 14, 2011 by 72 Comments

This odd-looking ball can automatically take a panoramic image whenever you throw it up into the air. Seriously, that’s then entire set of operating instructions for the device. Inside, a 3D printed frame hosts an array of 36 cellphone cameras, each capable of taking a two megapixel image. Also included is an accelerometer. When it senses the change in momentum associated with the apex of its vertical trajectory it snaps an image with all of the cameras at the same time. The result is a spherical image with no obstructions-like a tripod or other support mechanism. The images are automatically stitched together and displayed on a computer which allows the user to pan and zoom.

The whole story is told in the video after the break. The example images shown are quite good, although there are a few artifacts where the segments meet. Most notably, color variances between the images captured by different CCD modules. We’d image that this can be fixed automatically in software if a talented programmer were willing to put in the time. The thing about spherical photos is that methods using post processing to unwrap an image always have some distortion to them. With that in mind, we think the ball camera is as good a solution as we’ve seen.

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HaD Links – Quakepocalypse Edition: August 23, 2011

August 23, 2011 by 22 Comments

Well, if you hadn’t noticed the news there has been a little bit of a shakeup on the east coast. I just arrived home after being evacuated due to a 30 second rumble the likes of which has not been felt on the east coast in something like 114 years. In lieu of the not so devastating but earth shaking event we thought we’d put together a few earthquake related links for you.

Earthquake-proof Wine Rack

First off instructables user [jofish] has a quick remedy if earthquakes are constantly destroying all the wine on your wine rack. He researched some existing commercial products and simply copied them by stapling cheap O rings to the front of the rack. We assume the back of the wine rack is secured to the wall as well.

Vertical Seismometer

Next up is a vertical seismometer from [Mike] over at mikesense.com. This was in response to a slightly more threatening 7.2 earthquake he experienced in Baja California last year. A vertical seismometer measures the movement of a weight either electronically or mechanically, and then damps the motion of the oscillation by a magnet or some other means. This particular design is known as the AS-1 developed by [Jeff Batten]. Matt’s page has links to everything you’d need to know including build videos.

Predict Seismic Activity with Hard Drives

If you are looking for some non-conventional ways of tracking seismic activity we have a pair of articles that detail earthquake tracking using your disk drive’s accelerometer. [Michael Stadler] realized the potential for all these sensors and released a program that creates a peer-to-peer network compiling data from the sensors. We are not too comfortable with the prospect of somebody tracking every time we drop or kick (or drop-kick) our laptops but 2500 users in Asia downloaded the software in ’06. The second article details an effort lead by IBM to monitor the fixed hard drives in server racks which generally remain far more stationary.

Simple DIY Earthquake Simulator

Finally for those of you who want to cause (miniature) earthquakes, we dug up this MTU project using plywood, an electric drill, rubber bands and some bearings to fabricate a DIY shake table (PDF warning). We are sure there are tons of improvements that can be made but this is a pretty fun project if you have a bunch of CNC parts lying around (we wish we did).