Drums Anywhere!

The students over at Cornell’s School of Electrical and Computer Engineering have been hard at it again with their senior projects. This time, it’s the very tiny and portable drumset dubbed Drums Anywhere by its creators [Shiva Rajagopal] and [Richard Quan]. Since there are other highly portable instruments like roll-up pianos, they suppose there should be a portable drum kit that actually sounds like drums, and this ECE duo have hit the metaphorical and physical drum on the head… except that this project doesn’t actually use physical drums to make sound.

The project consists of two 3D-printed box-like sensors with velcro straps that can be attached to any drumstick-shaped object that might be lying around. Inside the box is a flex sensor and a tiny microphone which report the “beats” to a microcontroller when they strike another object.

On the software side, there are two sampled sounds stored in the microcontroller but they plan to add more sounds in the future. The microcontroller outputs sound to a pair of speakers, and the sensors are sensitive to force, so the volume can range from almost inaudible all the way up to [John Bonham]-style booms. This could also be theoretically expanded to include more than two “beat boxes” for extra sounds, or be wireless. The options are virtually limitless, although the team notes that they are limited by the number of interrupts and ADC converters on their particular microcontroller, an ATmega1284.

This is another interesting take on a having drumset without the drums, and definitely expands the range of what a virtual drum set can do. It’s also great to see interesting projects coming from senior design classes! Be sure to check out the video after the break.

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Stewart Platform Ball Bearing Balancer

PID balancing a ball on a plate

For their Mechanical Engineering senior design project at San Jose State University, [Tyler Kroymann] and [Robert Dee] designed and built a racing motion simulator. Which is slightly out of the budget of most hackers, so before they went full-scale, a more affordable Arduino powered Stewart platform proof of concept was built. Stewart platforms typically use six electric or hydraulic linear actuators to provide motion in six degrees of freedom (6 DOF), surge (X), sway (Y), heave (Z), pitch, roll, and yaw. With a simple software translation matrix, to account for the angular displacement of the servo arm, you can transform the needed linear motions into PWM signals for standard hobby servos.

The 6 DOF platform, with the addition of a resistive touch screen, also doubled as a side project for their mechatronic control systems class. However, in this configuration the platform was constrained to just pitch and roll. The Arduino reads the resistive touch screen and registers the ball bearing’s location. Then a PID compares this to the target location generating an error vector. The error vector is used to find an inverse kinematic solution which causes the actuators to move the ball towards the target location. This whole process is repeated 50 times a second. The target location can be a pre-programmed or controlled using the analog stick on a Wii nunchuck.

Watch the ball bearing seek the target location after the break.

Thanks to [Toby] for sending in this tip.

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Autonomous tank terrorizing campus

tank

As a senior design project for ECE4007,  [Nate], [An], [Chris], and [Wink] built an autonomous toy tank. It is using a Panasonic IR motion sensor to find targets, then once it’s facing the target it switches to visual motion tracking through it’s web cam. If it can get close enough, it will stop and begin rotating the turret for more accuracy. Finally it fires a pellet. It’s brains are an ICOP technology eBox-2300 running windows CE. All of the programming is available on the site, as well as a breakdown of the various sensors and hardware. As you can see in the video after the break, it does a decent job. Given some more time, we’re sure they could speed up the target acquisition process. Maybe we should add a category for Georgia Tech final projects.

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