Arduino Day 3 - Introducing Frank the Sciborg

1. Have an LED blink an SOS message.

2. Download Bricktronics application.  Run "Single Motor" example.

3.  Modify the code to include both motors.

4.  Find the minimum speed.  For our sciborg, we found the speed at which the wheels do not move to be 58.

5.  Have the sciborg make a hard turn.  This is achieved by making the speed of one motor 0 while the other one was at 150.

6.  Have your sciborg make a gentle turn.  This was achieved by making one motor slightly faster than the other.

7.  Have the sciborg travel 10 feet and then stop.

8.  Try to make the sciborg go straight.  This code made the sciborg move slightly to the right.

We changed the speeds to correct for this slight turn to the right.  Now it moves slightly to the left!

9.  Have the sciborg move forward, hit a wall, then back up, turn and go.

We encountered much difficulty in trying to make Frank go straight, but it was impossible to perfect.  It could be due to the wheel in the front that swivels in all directions.

Arduino Day 2 - Servo, Potentiometer, and Photocell!

We continued using the arduino to control LEDs and servos using input from a potentiometer and a photocell.

1. Connect Servo to Arduino and run "Sweep" example.                                                                                  
   
   
   
   
   
   
   
2. Modify "sweep" program to make the servo move faster.  (increments of 10 degrees)
   
   
   
   
   
   
   
3. Connect Potentiometer and run "Knob" example.  We noticed that the servo moves as we turn the knob.
   
   
   
   
4. Modify "knob."  We change the values of the potentiometer to go from 0 to 500, making the servo move 180 degrees when the knob is turned halfway.
   
   
   
   
   
   
   
   
5. Control blink rate of LED using a potentiometer.
   
   
   
   
   
   
   
6. Connect a photocell and use it to control the LED and servo.  When the photocell senses dark or dim, the LED turns on and moves the servo to one position.  When the photocell senses bright or very bright, it turns the LED off and moves the servo to the other posion.
   
   
   
   
   
   
   
   
7. Change the blink rate of the LED based on readings from the photocell.
   
   
   
   
   
   
   
   
   
   

Arduino Day 1 - LEDs!

Arduino is a tool used for feed back and control systems.  Our first project with Arduino involves LEDs!

1. Make sure the Arduino is functioning by plugging it in and run "Blink with Delay" program in examples.
   
   
   
   
2. Remove delay.  This makes the light blink so fast, we do not see the change from on and off and it is as if it is on the entire time.
   
   
   
   
   
   
   
3. Change blink pattern to on for 2 seconds and off for 1/2 second.
   
   
   
   
   
   
   
4. Connect an LED to pin 13 and create a cool pattern with the LED and pin 12. Our first step was the visualize the pattern we desired.  Each light is on or off for 250 miliseconds. It starts with both pins on, then both off, then one on and the other off, then both off and then one one and the other off and then both off.
   
   
   
   
   
   
   
   
   
   
5. Add more LEDS into the other pins and make cool patterns!
   
   
   
   
   
   
   
   Since we had time, we made another one!
   
   
   
   
   
   
   
   
   
6. Blinking without delay command using current millis.
   
   
   
   
   
   
7. Make a cool pattern without the delay command and with current millis.
   
   
   
   
    
   
   
    We did another one! 

Playing with the Arduino and LEDs was so much fun!

CSC Visit and Project Ideas

We visited the CSC on campus to observe children and listen to the concerns of the teachers.  Our hope is to create a product that will somehow aid or benefit the children and their teachers.

A list of issues we encountered in at the CSC:

1. Children have trouble staying on their mats.

• For this issue, we can design a mat where the children feel engaged and excited to sit down.  This can incorporate LEDs that play a certain pattern as soon as the child sits.

1. Children become very loud.

• For this issue, we can design a meter that detects a certain threshold of noise and alerts them using LEDS, faces, and messages.

1. Children splash water onto the ground, making the floor wet and hazardous.

• For this issue, we can place sensors on the edges of the box that detect drastic movement that may splash water onto the ground.  Children can be alerted by a flashing LED or a message.

1. Children are scared to or have difficulty flushing the toilet

• For this issue we can have a string that the children pull or a button they press to flush the toilet.  The toilet will then sense the children leaving and proceed to flush.

1. Children need to remember to wash their hands and wash them properly.

• For this issue we can add a sensor to the water that detects a flush and a child close in order to turn on an LED that will draw the child's attention and remind them to wash their hands.  And LED can also be connected to the soap to remind them to use it.  The light will not turn off until the child washes their hand for at least 10 seconds.

Physics and Engineering Seminar

Today I attended a lecture given by Professor Robert Wood from the Harvard School of Engineering and Applied Sciences.  He talked about creating robots on an extremely small scale; the size of a house fly!  If the robot is that small, imagine how small the its parts must be!

The part of his lecture I found very interesting was the process of assembly.  He joked about graduate students spending weeks putting together the parts using tweezers.  He then told us about how looking at origami and his sons pop-up books gave him the idea to assemble the robotic insects in a similar way. A detailed explanation can be found in this video:

Another method of assembly was self folding, as seen in the following video:  Self-folding with shape memory composites

He also showed us some other really cool designs like this centipede:

Another aspect I liked about his work is how interdisciplinary it is, combining math, physics, biology, engineering, computer science and even arts like oragami. 

Sidenote:  I've always felt uncomfortable about seeing insects in the restroom.  Now my fears of being spied on by them during private hours have more legitimacy.

Assignment 3: Mechanisms

There is something very pleasing about watching gear mechanisms work in an infinite loop!

Browsing through Cornell's Kinematic Models for Design Digital Library, there were so many interesting mechanisms.

I found Model: O05 Planetary Gear, Slider-Crank Kinematic Chain from Cornell's Reuleaux Collection very compelling.

Planetary gear trains (or epicyclic gear trains) are not attached to fixed bodies.  Instead, the links holding the center of the gears move.  Since all the links can move, the train value can be changed by using different gears or carriers. This functionality makes planetary gear trains useful in automotive transmissions.

Below is an image of a basic planetary gear train.

https://memechanicalengineering.files.wordpress.com/2014/02/machines-and-mechanisms.pdf

The central gear (1) is called the sun gear.  The planet gear (3) revolves around the sun, hence the name planetary gear.  The carrier (2) holds the planets in orbit around the sun.This sun/planet gear system is usually inclosed in a ring gear (4).

http://kmoddl.library.cornell.edu/stillImages/small/O05.jpg

In Model O05 from Cornell's library, "there are five links. The fixed base holds two revolute joints. The sliding guide is constrained to the base by one of the revolute joints and constrained to the rod that is fixed to the larger gear. The pinion gear is affixed to another link that rotates on a revolute joint at the base. Finally, there is a link connecting the two gear wheels by two revolute joints. The model is designed so that it can be removed from its base and the large gear fixed as a sun gear and the pinion roll as a planet gear. The pinion has 26 teeth and the larger gear as 52 teeth."

Another gear mechanism I found very beautiful involves its application to art, which can bee seen in this video:

Assignment 2/Part 2 of 2: Windlass

We started by brainstorming general designs:

Initially, we decided on a triangular design:

Professor Banzaert recommended an A-frame, explaining that our triangle structure may not hold up to the weight of the bottle.  We began out calculations, keeping several A type frames in mind:

While designing our parts on SolidWorks, we felt that a full semi-circular plate would make our design strongest in terms of foundation.  The stronger the better! This would decrease the risk of any unforeseen accidents and in turn decrease our number of iterations.  

Our design involved using bushings, pegs, and notches.  We made three iterations of each method to ensure the tightest fit.

We knew any initial paper calculation would change once we began designing our parts in SolidWorks and so to save time, we made all our calculations with the program.

Yay, time to print!

Immediately after assembling our parts, we tested it with the 1 liter bottle. 

Although the foundation was strong and did not collapse inward, we found the weight of the bottle turned the four outer rods in a direction that was opposite to the direction the center rod was turning.

To fix this issue, we piano wired the two center plates (holding five rods) to the center  rod.  In order ensure that the center rod did not turn in a direction that was opposite to the direction the wheel was turning, we piano wired the wheels to the center rod as well.  Just to be extra safe, (and also because we wanted to use the machine!) we heat staked the outermost bushings to the center rod to ensure our wheel would not move or fall off.

The most difficult part of this project was getting the drill press to align with the center plates, wheels, and with the rod, and drill completely through from the top, through the rod, and to the bottom.

We were SO HAPPY it worked!  Out of excitement we accidentally pushed the windlass off the table TWICE but it STILL held up nicely!

There were two requirements we forgot to check while going over our design:

1. The bottle must rise 10cm above the table. 

2.  We may use only one handle.

    Since we gave ourselves a lot of room to make changes by staying well under the limit of 500cm^2, a simple change it plate size will fix the first issue.

Technically speaking, our windlass does work with one handle! Two handles make sure the structure is well balanced on both sides and also makes pulling the bottle  up a faster process.  In a real world situation, individuals would be able to use the well from both sides or even pull larger loads of water when two people are turning the wheel together.  This makes for a very practical and efficient windlass.

Exact measurements coming soon!