Modeling an object with internal IMUs

April 26, 2012 By Leave a Comment

[Joseph Malloch] sent in a really cool video of him modeling a piece of foam twisting and turning in 3D space.

To translate the twists, bends, and turns of his piece of foam, [Joseph] used several inertial measurement units (IMUs) to track the shape of a deformable object. These IMUs consist of a 3-axis accelerometer, 3-axis gyroscope, and a 3-axis magnetometer to track their movement in 3D space. When these IMUs are placed along a deformable object, the data can be downloaded from a computer and the object can be reconstructed in virtual space.

This project comes from the fruitful minds at the Input Devices and Music Interaction Lab at McGill University in Montreal. While we’re not quite sure how modeled deformable objects could be used in a user interface, what use is a newborn baby? If you’ve got an idea of what this could be used for, drop a note in the comments. Maybe the Power Glove needs an update – an IMU-enabled jumpsuit that would put the Kinect to shame.

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Climbing the mountain of quadcopter design

April 24, 2012 By Leave a Comment

What a sweet thing it is to see the first outdoor flight of a quadcopter. [Botched] has done a wonderful job of documenting the entire build process. Take a look at all that he has done, then jump after the break to see the extremely stable test flight footage.

Earlier iterations used feedback electronics that he designed, etched, and soldered himself. We think they looked pretty good, but he was not happy with the performance. He spent a bunch of time redesigning the IMU board, but after he printed out the PCB artwork he decided his soldering was not up to the QFN challenge and he went with a pre-assembled breakout board.

His post about PID tuning is quite interesting. He removed two of the motors and mounted those opposite ends of the chassis to a hinged stand. This let him tweak the feedback loop until the two remaining propellers were able to maintain balance even when he nudged the unit.

His test flight footage is accompanied by an on-board camera shot. He simply taped a smart phone to the battery and let it roll. Make sure you turn off your speakers before watching this one or the motor noise will let the boss know you’re reading Hackaday again instead of working.

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Short and squat balancing bot is extremely stable

March 7, 2012 By Leave a Comment

[Lauszus] really put together an impressive self balancing robot platform. It is virtually motionless when balancing in place, and that stability is never lost even when motoring across the room.

Part of the success behind this build is the use of quality components. He’s got a really nice set of motors with built-in encoders which give feedback to the balancing system. They work in conjunction with a gyroscopic sensor and PID code to keep the two-wheeled platform upright. An mbed board running 96 MHz provides plenty of computing power for the balancing system. But an Arduino can also be found on board. This was included to facilitate Bluetooth connectivity with the remote control as [Lauszus] didn’t want to port the code he had already written.

The fourteen minute video after the break shares the details behind how the PID controller is tuned and how [Lauszus] implements target angle and a few other factors. Of course he talks about the hardware choices, and demonstrates functionality by driving the bot around using a wireless PS3 controller.

The construction method which uses masonite strips and threaded rod does a good job of protecting the hardware mounted on it. We’re always a bit worried about these bots falling over and some of the projects we see offer little or no protection. Once thing that helps protect against a spill is a piezo buzzer which sounds when the battery is getting low.

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