Team Scores Big Points With Pinball Final Project

For their final project in [Bruce Land]’s class on designing with PIC32 microcontrollers, [Sujith], [Julia] and [Andrew] wanted to do something fun. And what could be more fun than bending to the electromechanical siren song of the pinball machine?

This machine looks great, and as you can see in the demo video after the break, it plays and sounds great, too. We particularly like the boomerang obstacle and the game state-driven LED strip. The more points you score, the brighter they go. We also like that this machine combines traditional scoring methods with a few really clever ones, like the boomerang target near the top and the scoring triggers made from copper tape.

The team started by designing the heart of any pinball machine, the flippers. Though we have seen car door lock actuators used in homebrew machines, the team went with traditional solenoids to drive them. Unfortunately the solenoids caused a lot of interference, but the team got around it with filter capacitors and aluminium foil Faraday cages around the wires.

If all this pinball talk has your circuits lit up, why not try making your own machine? Continue reading “Team Scores Big Points With Pinball Final Project”

Tweetbot Expresses Twitter Emotions

When reading textual communications, it can be difficult to accurately acertain emotional intent. Individual humans can be better or worse at this, with sometimes hilarious results when it goes wrong. Regardless, there’s nothing a human can do that a machine won’t eventually do better. For just this purpose, Tweetbot is here to emotionally react to Twitter so you don’t have to.

The ‘bot receives tweets over a bluetooth link, handled by a PIC32, which also displays them on a small TFT screen. The PIC then analyses the tweet for emotional content before sending the result to a second PIC32, which displays emotes on a second TFT screen, creating the robot’s face. Varying LEDs are also flashed depending on the emotion detected – green for positive emotions, yellow for sadness, and red for anger.

The final bot is capable of demonstrating 8 unique emotional states, far exceeding the typical Facebook commenter who can only express unbridled outrage. With the ‘bot packing displays, multiple microcontrollers, and even motor drives, we imagine the team learned a great deal in the development of the project.

The project was the product of [Bruce Land]’s ECE 4760 course, which has shown us plenty of great hacks in the past – Bike Sonar being one of our favorites. Video after the break.

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A Robot Arm For Virtual Beer Pong

Leave it to engineering students to redefine partying. [Hyun], [Justin], and [Daniel] have done exactly that for their final project by building a virtually-controlled robotic arm that plays beer pong.

There are two main parts to this build: a sleeve worn by the user, and the robotic arm itself. The sleeve has IMUs at the elbow and wrist and a PIC32 that calculates their respective angles. The sleeve sends angle data to a second PIC32 where it is translated it into PWM signals and sent to the arm.

There’s a pressure sensor wired sleeve-side that’s worn between forefinger and thumb and functions as a release mechanism. You don’t actually have to fling your forearm forward to get the robot to throw, but you can if you want to. The arm itself is built from three micro servos and mounted for stability. The spoon was a compromise. They tried for a while to mimic fingers, but didn’t have enough time to implement grasping and releasing on top of everything else.

Initially, the team wanted wireless communication between the sleeve and the arm. They got it to work with a pair of XBees, but found that RF was only good for short periods of use. Communication is much smoother over UART, which you can see in the video below.

You don’t have to have a machine shop or even a 3-D printer to build a robot arm. Here’s another bot made from scrap wood whose sole purpose is to dunk tea bags.

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Motorized Camera Dolly Rolls With The Changes

Over the last semester, Cornell student [Ope Oladipo] had the chance to combine two of his passions: engineering and photography. He and teammates [Sacheth Hegde] and [Jason Zhang] used their time in [Bruce Land]’s class to build a motorized camera dolly for shooting time-lapse sequences.

The camera, in this case the one from an iPhone 6, is mounted to an off-the-shelf robot chassis that tools around on a pair of DC motors. The camera mount uses a stepper motor to get just the right shot. A PIC32 on board the ‘bot takes Bluetooth commands from an iOS app that the team built. The dolly works two ways: it can be controlled manually in free mode, or it can follow a predetermined path at a set speed for a specified time in programmed mode.

Our favorite part of the build? The camera’s view is fed to a smart watch where [Ope] and his team can take still pictures using the watch-side interface. Check it out after the break, and stick around for a short time-lapse demo. We’ve featured a couple of dolly builds over the years. Here’s a more traditional dolly that rides a pair of malleable tubes.

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