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
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