Day 12: Data Files | LCD Displays

Lab

LCD Displays

LCD displays can display values on the screen, and also allow someone to interact with it by pressing buttons on it.
1023
Select: 740-741
Left: 503
Down: 326-327
Up: 142-143
Right: 0

Lecture

Data Files

I/O Statements

Must use pointers to reference
file pointer defined with FILE declaration as in FILE *sensor1;
Asterisk before identifier specifies that identifier is a pointer

sensor=fopen("sensor1.txt","r");

fopen function optains info needed to assign file pointer for specific file.
R is for read, w is for write

Homework

Hardware

//LCD with Progress Bar

//Include the library code:

#include <LiquidCrystal.h>

//Initialize the library with the numbers of the interface pins

LiquidCrystal lcd(8,9,4,5,6,7);

//Create the progress bar characters

byte p20[8] = {

B10000,

};

byte p40[8] = {

B11000,

};

byte p60[8] = {

B11100,

};

byte p80[8] = {

B11110,

};

byte p100[8] = {

B11111,

};

void setup()

{

pinMode(11,OUTPUT);

//Set up the LCDs number of columns and rows:

lcd.begin(16, 2);

// Print a message to the LCD.

lcd.print("ENGR6 Display");

//Make progress characters

lcd.createChar(0, p20);

lcd.createChar(1, p40);

lcd.createChar(2, p60);

lcd.createChar(3, p80);

lcd.createChar(4, p100);

}

void loop()

{

//Move cursor to second line

digitalWrite(11,HIGH);

lcd.setCursor(0,1);

//Clear the line each time it reaches the end

//with 16 " " (spaces)

//lcd.print(" ");

//Iterate through each character on the second line

for (int i = 0; i<16; i++)

{

//Iterate through each progress value for each character

for (int j=0; j<5; j++)

{

lcd.setCursor(i, 1); //Move the cursor to this location

lcd.write(j); //Update progress bar

delay(100); //Wait

}

Software

The homework asked us to print the velocity and altitude of a weather balloon given a starting time, ending time, and increment. We also needed to modify it to find the maximum, check that the user's inputs made sense, and to write it to a text file.

Code:
//Weather Balloon
/*This program prints the altitude and velocity for a weather balloon
with a given start time, increment in time, and ending time*/

#include <stdio.h>
#include <math.h>
#define FILENAME "balloon.txt"

int main(void){
float startTime, incTime, endTime, alt, vel, t;
FILE *balloon;
balloon=fopen(FILENAME,"w"); //Open output file

//Take user inputs
printf("Input start time in hours: ");
scanf("%f",&startTime);
printf("\n Input end time in hours: ");
scanf("%f",&endTime);
printf("\n Input time increment in minutes: ");
scanf("%f",&incTime);
incTime=incTime/60; //Convert minutes into hours

float maxAlt=0, maxAltTime, velMS, totalVel;
float totalMaxTime, totalMaxAlt=0, totalAlt;

int j=0;

if(j==0)
{
while(endTime<=startTime) //Make sure that the starting time is less than the ending time
{
printf("\n End time must be greater than start time\n");
printf("Please re-input times\n");
printf("Input start time in hours: ");
scanf("%f",&startTime);
printf("\nInput end time in hours: ");
scanf("%f",&endTime);
}

while(startTime>=48 || startTime<0)//Make sure start time falls in proper range
{
printf("\n Start time must be between 0 and 48 hours. Re-enter start time\n");
printf("Input start time in hours: ");
scanf("%f",&startTime);
t=startTime;
}

while(endTime>=48 || endTime<0)//Make sure end time falls in proper range
{
printf("\n End time must be between 0 and 48 hours. Re-enter end time\n");
printf("Input end time in hours: ");
scanf("%f",&endTime);
}

while(incTime>=48 || incTime<0)//Make sure time increment falls in proper range
{
printf("\nTime increment must be between 0 and 48 hours. Re-enter time increment\n");
printf("Input time increment in minutes: ");
scanf("%f",&incTime);
}

if(startTime<endTime)
{
t=startTime;
printf("Time Altitude Velocity\n");
while(t<=endTime)
{
alt=-0.12*pow(t,4) + 12*pow(t,3) - 380*t*t + 4100*t + 220; //Calculate altitude
vel=-0.48*pow(t,3) + 36*t*t - 760*t + 4100; //Calculate velocity
velMS=vel/3600; //Covert meters per hour to meters per second

printf("%.4f %.4f %.4f \n",t,alt,velMS); //Print values in console
fprintf(balloon,"%7.4f %7.4f %7.4f \n",t, alt, velMS); //Print values to file
if(alt>maxAlt)
{
maxAlt=alt; //Find maximum altitude and time that balloon reaches altitude
maxAltTime=t;
}
t+=incTime; //increment time

if(t>=endTime)
{
j=1; //Break from loop
}
}

for(int i=0; i<=191; i++) //Find max altitude for all 48 hours
{
int k=i*0.25;
totalAlt=-0.12*pow(k,4) + 12*pow(k,3) - 380*k*k + 4100*k + 220;
if(totalAlt>totalMaxAlt)
{
totalMaxAlt=totalAlt;
totalMaxTime=k;
}
}
}
}
//Print max altitude for range
printf("The maximum altitude for the specified range is %.4f meters, and is reached at time %.4f hours after balloon launch\n",maxAlt,maxAltTime);
//Print max altitude for entire flight
printf("\nThe maximum altitude during the entire flight is %.4f meters, and is reached at time %.4f hours after balloon launch\n",totalMaxAlt,totalMaxTime);
//Close file
fclose(balloon);
return 0;

}

Day 25: Python, Graphing, 3D Visualization and Inertial Measurement

Python Arduino Code int trigPin=13; //Sensor Trig pin connected to Arduino pin 13 int echoPin=11; //Sensor Echo pin connected to Arduino pin 11 float pingTime; //time for ping to travel from sensor to target and return float targetDistance; //Distance to Target in inches float speedOfSound=776.5; //Speed of sound in miles per hour when temp is 77 degrees. void setup() { // put your setup code here, to run once: Serial.begin(9600); pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); } void loop() { // put your main code here, to run repeatedly: digitalWrite(trigPin, LOW); //Set trigger pin low delayMicroseconds(2000); //Let signal settle digitalWrite(trigPin, HIGH); //Set trigPin high delayMicroseconds(15); //Delay in high state digitalWrite(trigPin, LOW); //ping has now been sent delayMicroseconds(10); //Delay in low state pingTime = pulseIn(echoPin, HIGH); //pingTime is presented in microceconds pingTime=pingTime/1000000; //convert pin...

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