PROGRAMMING AND ROBOTS AND CENTRIFUGES, OH MY!

Group FourCatherine Fahey, Steven Falzerano,

Nicollette Fernandez, Eliot M. Fine and Stefan Toubia

Los Jefes

Darth Vader

ObjectiveTo create a robot that follows a course laid out in black tape,

make a u-turn, and return to the starting line following the tape

again.  In doing so, we can learn more about Interactive C

programming and the Handyboard.

Resources

Handyboard 2 motors 2 analog light sensors,

Lego's (this includes treads, wheels, and gears)

Procedure: We chose:

Treads: because the robot was able to make the adjustments more easily, and also the robot got more traction 

Gears: because the motors were too weak to actually move the robot

Our trial-and-error process helped us come to these

conclusions.

Codevoid main(){ int lap; lap=0;    while(start_button()==0){}    while(1){        if(analog(5)<200 && analog(6)<200){            motor(1,100);            motor(3,100); // if the light sensors read white then both motors go forward at a speed of 20        }        else if(analog(5)>=200 && analog(6)<200){            motor(1,-100);             motor(3,100); // but if analog 5 reads dark (the black tape), then the robot will turn right        }        else if(analog(5)<200 && analog (6)>=200){            motor(1,100);            motor(3,-100); //but if analog 6 read dark, then the robot will turn left         }        else if(lap==0 && analog(5)>=200 && analog (6)>=200){            motor(1,-100);            motor(3,100);            sleep(1.5); //the robot reads dark, then the robot will make a u-turn and head to the start line            while(analog(5)<200{};            lap ++; //new lap, repeats above but goes to next statement when reaches start line            }        else{            ao();// robot turns off once at start line again        }    }}

Challenges: Friction

Our original design (3 wheels: 2 with tires, 1 without), did not pick up enough friction

Switched to treads○ Motors were too weak, so we had to add gears to help give more force

BUILDING A CENTRIFUGE

What is a Centrifuge? A piece of equipment that rotates about an

axis Uses centrifugal forces to separate

substancesHeaviest molecules move to the bottom of the

tube Used in biology, chemistry, and aeronautics

Separate substances Meselson and Stahl experiment

Set Up Used: IR “Top-Hat” sensor, scotch tape and a

cuvette, gears, wheels Constructed:

Base of legos Motor with gears to create an axelT-shaped crossbar attached to the axelOne side had a cuvette the other had a

counterweightTires attached to base to act as shock absorbers

and supports*Note: need white paper behind cuvette

die Windmühle

Codevoid main(){

int speed=0;float separation_time=5.0; // Time, seconds, that centrifuge will spinfloat ramp_time=0.1; // Time, seconds, between speedsprintf ("\nHold Down Start Button to Take Readings");while (start_button()==0) {}while (start_button()==1) { // Top-Hat reads while button is pressedprintf ("\nAmount mixed is %d", analog(3));sleep (0.2);}while (speed<=100) { // Speed gradually increases from 0 to 100printf ("\nSpeed is %d",speed);motor (1,speed);sleep (ramp_time);speed++;}sleep (separation_time); // Centrifuge spins for specified time at 100while (speed>0) { // Speed gradually decreases from 100 to 0printf ("\nSpeed is %d",speed);motor (1,speed);sleep (ramp_time);speed--;}ao();while (speed==0) { // Everthing shuts off and Top-Hat reads againprintf ("\nMixation = %d, Did they separate?”,analog(3));sleep (0.2);}

}

http://tinypic.com/player.php?v=34njo6s&s=4

Data:

Trial #

Sensor Rading (before

separation)Sensor Reading (after

separation)Ramp UP Time (s)

Time to Separate (s)

Ramp DOWN Time (s)

    Oil Water

   

1 13 128 9

0.1     

0.5     

 0.1    

2 12 118 83 24 122 104 10 88 105 9 95 13

Conclusions We learned:

○ From the Robot:○ Treads are slower but they have more traction○ Going from big gears to small gears increases speed and

from small gears to big gears increases torque○ A sturdy frame is crucial

Improvements:○ Our code could have had a slower, more careful turn, so

that it would not whip around Improvements with the centrifuge:

○ Faster motors, more durable parts, more easily-removable cuvettes, a built-in IR sensor

○ The code did work extremely well though