Tactile Simon Completed 
by aburks on Dec.05, 2010, under Personal Projects, Simon
I was able to complete the game of Simon that I was developing for my cousins in time. The hardest part by far was getting the IR sensors to cooperate. Here are some photos of the final product, followed by a really artistic video my roommate Mike made for me.
Overall
Two versions: Lombardo and Buss
Very Bright LEDs
Everything Connected to Top Structure
Electronics on the Back
Arduino with Tons of Inputs and Outputs
IR Emitter/Detector Breakout Board
MOSFET Board
Robotic Manipulation Cup Stacking
by aburks on Dec.02, 2010, under Classwork
Challenge
For the final lab assignment in my Robotic Manipulation class, we were challenged to competitively stack cups. We were given six 3 inch tall plastic cups, and were instructed to make a 3-2-1 pyramid out of them, then destroy the pyramid, as quickly as possible. Before we even began working on the project the best team had already done it in only 12 seconds.
The robot arm is currently equipped with a descent pneumatic gripper. Two big plastic pads squeeze the cups one at a time to contain them. Stacking cups one at a time is inefficient, but teams were doing it. Nico and I decided that we needed a some mechanical advantage.
Design Goals
The biggest design limitation was that the only way to actuate our device would be to integrate with the existing gripper. This limits us to on-off control, which prevents us from picking up all of the cups at once and releasing them strategically.
However, the bottom stack doesn’t really need to be picked up, it only needs to be slid across the tabletop. Also, picking up two cups at once for the middle layer saves time as well. The top cup could even be optimized by dragging it into the stacking area initially. If any of these goals could be met, it would give us an advantage over the other teams.
Interface
In our previous lab, we were able to use the gripper to attach our end effector to the DENSO arm. However, because we rely on the actuation of the gripper to activate our mechanism, we needed an alternate means of attachment. The T-slots on the end of the DENSO arm are the perfect size for a 1/4” nut, which is the standard size for a #4 bolt. Attaching here gave us a reliable fixed reference point.
Fabrication
Using the robotics club CNC, I was able to build the 6 parts necessary for the device. The only problem I encountered was bowing and vibration in the middle of the largest piece. Because my piece (11.58”x3.68”) was near the maximum limits of the machine (12”x4”), it was difficult to secure the middle of the stock. All in all, it took about 5 hours of machining to build the entire mechanism, half of which was slow-going CNC time on the largest piece.
Performance
In the end, we were able to achieve a time of 5 seconds. Nico and I are pleased with the results, and expect to have the fastest time in the class.
Tactile Simon
by aburks on Nov.18, 2010, under Personal Projects, Simon
Years ago, when I was in elementary school, my cousins Lisa and Erin would always give my brother and I great Christmas gifts when the extended family got together for Thanksgiving. Now that they both have kids of their own, I thought it was about time to repay them. Two weeks before Thanksgiving this year, I got the idea to use my robotics experience to make a toy for each of the families.
Idea
I wanted a toy that was interactive, but simple. I needed moving parts, but nothing fragile or exposed. Somehow I came up with the idea to do a tactile version of Simon. All I knew was that I wanted a wheel you could grip that would spin in a pattern that you had to repeat. The toy needed to be entirely encased to protect the electronics, but I wanted the kids to be able to see what was going on inside as well.
Design
Mechanism
On top there is a wheel with four colors on it and notches around the outside for gripping. The top wheel is made of clear polycarbonate and the colors are printed on transparency paper and attached with contact paper. This design lets the LED in the notch below one section of the wheel illuminate the active color by shining through the colored transparency.
There is a second wheel below the top cover, but it is constrained to rotate with the top wheel. It is made of white HDPE, with strategic portions of its bottom surface colored black. Both of these circles are attached to a Servo which can rotate the wheels in either direction at variable speeds.
Interface
The primary sensors on this robot are the four IR emitter/detector pairs. A combination of an infrared LED and phototransistor, these sensors allow a microcontroller to determine how reflective a surface is. Because white surfaces are more reflective than black surfaces, this sensor pair can parse the pattern of black and white on the bottom wheel. Combined, these sensors tell the robot how the wheel is oriented.
Besides the power switch, the only other input device on the robot is the button on the left of the device. After turning the wheel to a certain color, pressing this button will log the current color as your next guess at the pattern.
There are two LEDs on the robot. One is in a cutout below the top wheel, and it is used to indicate the currently active color. The second LED is an RGB LED, so it it capable of producing different colors on its own. Displaying Red, Yellow, Green, or White during different portions of the game provides great visual feedback for the user.
Finally, there is a buzzer which allows the toy to make noises all across the audible range of human hearing.
Electronics
Everything plugs back in to an Arduino Duemilanove, which does all of the thinking. Most of the components only need to be plugged into the Arduino to be ready to go, but some of them need to go across a resistor or capacitor first. The IR emitter/detectors, however, are a bit of a pain. I had to make a board that slips female headers right over the sensors’ leads and routes them through all the proper resistors to finally output a sensible signal to the Arduino.
The servo requires some special electronic attention. Because I want people to be able to backdrive the Servo, I need to completely disconnect it from its power supply when it is the human’s turn to spin the wheel. Using a custom MOSFET board designed by my friend Nico Paris for our RobOrchestra project, I was able to selectively power the Servo.
Robotic Manipulation Clock Lab: Working!
by aburks on Oct.26, 2010, under Classwork
After a total of around 4 hours on the robot, Nico and I got the arm to work! We have two modes: one that displays the current time, and one that will count off time from a predefined starting point. Here are some videos of us testing at about 1:10AM on Sunday night.
I had to modify the pen and eraser holder a little bit to make it work. I needed to make the drip area fatter, because the fingers don’t actually close all the way. Also, I needed to mount the pen and eraser at a really close angle, because it took two seconds to rotate the tool by 90 degrees, which was unacceptable. By adding a fancy part to the original assembly, I was able to make it all work.
