I wrote a basic program for the
Arduino to increase my knowledge of computer programming. I am studying to
become a mechanical engineer so computer programming although not a focus of my
studies is very important. A moderate knowledge of computer programming aids in
understanding the programs I may use in industry and will allow a solid
foundation if I ever need to create my own program for specialized analysis.
I wrote my program by first
researching for programs that are already created so I can analyze others' work
for well and poorly designed systems. Then I outlined my goals for my program
and then using the knowledge collected from research and from my background I
wrote a program that I believe meets my goals. While writing my program I
annotated each line of code to better understand what the code is doing for
later reference and for other's to understand my code easily.
My Written Arduino Code:
//TMP36 Pin Variables
int temperaturePin = 0;
//the analog pin the TMP36's Vout (sense) pin is connected to
the
//resolution is 10 mV / degree centigrade (500 mV offset) to
make
//negative temperatures an option
/*
* setup() - this function runs once when you turn your
Arduino on
* We initialize the serial connection with the computer
*/
void setup()
{
Serial.begin(9600);
//Start the serial connection with the computer to view the
result
//open the serial monitor last button beneath the file
bar
//(looks like a box with an antennae)
}
void loop()
// run over and over again
{
static int t;
// t is a local variable
t++;
// time increases with each loop
float celsius= getVoltage(temperaturePin);
//getting the voltage reading from the temperature sensor
celsius= (celsius- .5) * 100;
//converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge - 500mV) times 100)
float fahrenheit= (celsius*9/5)+32;
//converting the read temperature from celsius to
fahrenheit
Serial.println("Time [s]");
// prints the label for time
Serial.println(t);
// prints the time elapsed
Serial.println("Temperature [F] and [C],
respectively");
// prints the label temperature converted and read
Serial.println(fahrenheit);
// printing the temperature in fahrenheit
Serial.println(celsius);
// printing the temperature in celsius
Serial.println(" ");
// prints a space between each loop to help organize the
serial monitor
delay(993);
// delays 1 sec minus the error of approx 7 millisec per
loop from the
//arduino processing and looping, (error calculated
experimentally)
}
/*
* getVoltage() - returns the voltage on the analog input
defined by
* pin
*/
float getVoltage(int pin){
return (analogRead(pin) * .004882814);
//converting from a 0 to 1023 digital range to 0 to 5
volts
//(each 1 reading equals ~ 5 millivolts
}
My code in action:
Ice on 1/8in Aluminum (only 60 sec intervals displayed)
Time [s]
1
Temperature [F] and [C], respectively
72.96
22.75
Time [s]
60
Temperature [F] and [C], respectively
71.20
21.78
Time [s]
120
Temperature [F] and [C], respectively
68.56
20.31
Time [s]
180
Temperature [F] and [C], respectively
67.68
19.82
Hot tap water poured into plastic bottle:
Time [s]
1
Temperature [F] and [C], respectively
77.35
25.20
Time [s]
2
Temperature [F] and [C], respectively
77.35
25.20
Time [s]
3
Temperature [F] and [C], respectively
77.35
25.20
Time [s]
4
Temperature [F] and [C], respectively
78.23
25.68
Time [s]
5
Temperature [F] and [C], respectively
79.11
26.17
Time [s]
6
Temperature [F] and [C], respectively
79.11
26.17
Time [s]
7
Temperature [F] and [C], respectively
79.99
26.66
Time [s]
8
Temperature [F] and [C], respectively
80.87
27.15
Time [s]
9
Temperature [F] and [C], respectively
80.87
27.15
Time [s]
10
Temperature [F] and [C], respectively
81.75
27.64
My code is based off of the code found at http://www.oomlout.com/oom.php/products/ardx/circ-10. However, I modified the code to be
easier to read in the serial monitor output by including the time at which data
was collected and labeling the data. I also included measurements in both
Celsius and Fahrenheit to save time if conversion was needed. Lastly, I let my
program run for an hour so I could calculate the error in the time reading
caused by the Arduino looping the program and processing data. I then corrected
the delay time to take into account the error for accurate data collection.
