PROGRAMMING SENSORS
In the week 3 recitation, we used an arduino to build circuits with different sensors.
NEW CHALLENGE
We were no longer allowed to use a breadboard for these circuits. Instead, we had to use a wire connector to connect one part to multiple ports (more on that in the section about building a pressure sensor).
ULTRASONIC RANGER
Goal : To create a circuit that detects the presence of something close by it and measures and displays the distance away. In every day life, a circuit like this would be used in things that require a level of attention to surroundings such as a car sensor. It would likely be coupled with a light or buzzer to alert at certain distances.
1. Assembly
To create this circuit we followed a provided diagram using an ultrasonic ranger, wires, and the arduino board. 
Link to image & instructions
final circuit
2. Coding
We typed the code while looking at example code to know exactly where things belonged and why.
Essentially, this code displays the text "Sensor Test" and "ARDUINO UNO"when it is first setup. Following that, it goes through a loop of identifying and recording the distance of an object that is detected. Finally, it converts the distance that the computer identifies as volts into centimeters and displays that on the Serial Monitor or Plotter.
This step was most challenging because we are still learning the syntax and requirements of programming the arduino. It required us to pay very close attention to the details. For example, when we first tried to upload, it took three tries to verify the code due to missing semicolons and brackets. We also used pseudo-code to outline what variables and functions we needed. However, there were still a few requirements that didn’t come to mind until after comparing our code with the example.
Ultrasonic Ranger Code
long duration; //duration of the echo sound wave to detect object
int distance; //distance measurement
int trigPin = 3; //assigns pin values
int echoPin = 2;
void setup() {
pinMode(trigPin, OUTPUT); //pin 3 (trig pin) is an output
pinMode(echoPin, INPUT); //pin 2 (echo) in input
Serial.begin(9600); //9600 baud speed
Serial.println("Sensor Test"); //prints text in monitor
Serial.println("ARDUINO UNO"); //^
}
void loop() {
digitalWrite(trigPin, LOW); //read sensor
delayMicroseconds(10);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = duration * 0.034 /2;
Serial.print("Distance: ");
Serial.print(distance);
Serial.println(" cm");
}PRESSURE SENSOR
Goal : To build a circuit that measures and displays the pressure level applied to the sensor (high pressure, medium pressure, low pressure). Pressure sensors can be used to take a product and enhance the interaction capabilities. For example the iPhone’s haptic touch uses pressure sensitivity to increase the things the users can do with the product.
1. Assembly
We began by connecting the pressure sensor to power (5V) and immediately ran into a problem: We can’t use a breadboard, so how can we connect the resistor to ground, the sensor, and the analog input? This required the new skill we learned, wire connecting.
Link to diagram in instructions
2. Wire Connecting
We learned how to connect wires using a wire connector by twisting a wire around another. We had to connect two new wires to the resistor to allow it to connect to both the analog input and ground ports.
final circuit
3. Coding
We used example code for this circuit and read through it to understand the code. This code reads the analog pressure value and displays it as “No pressure”, “Light touch”, “Light squeeze”, or “Big squeeze” depending on the value read. It has a 500 ms delay to have breaks between the display of values.
Pressure Sensor Code
#define fsrpin A0
//Define variable to store sensor readings:
int fsrreading; //Variable to store FSR value
void setup() {
// Begin serial communication at a baud rate of 9600:
Serial.begin(9600);
}
void loop() {
// Read the FSR pin and store the output as fsrreading:
fsrreading = analogRead(fsrpin);
// Print the fsrreading in the serial monitor:
// Print the string "Analog reading = ".
Serial.print("Analog reading = ");
// Print the fsrreading:
Serial.print(fsrreading);
// We can set some threshholds to display how much pressure is roughly applied:
if (fsrreading < 10) {
Serial.println(" - No pressure");
} else if (fsrreading < 200) {
Serial.println(" - Light touch");
} else if (fsrreading < 500) {
Serial.println(" - Light squeeze");
} else if (fsrreading < 800) {
Serial.println(" - Medium squeeze");
} else {
Serial.println(" - Big squeeze"
}
delay(500); //Delay 500 ms.
}PRESSURE SENSOR WITH BUZZER
Goal : To build a circuit that measures, displays , and indicates with a specified noise the pressure level applied to the sensor (high pressure, medium pressure, low pressure). An example of a practical use of this is a digital piano which would use similar technology to produce varying volume levels and even different sounds.
1. Assembly
Most of the assembly was the same from the previous circuit. We only connected the buzzer to port A0 and ground on the arduino.
2. Coding
We also kept most of the same code. We only added tones to each if statement so that when pressure was applied, a sound is played and gets higher as more pressure is applied.
Lesson on clean and concise coding: Initially, while coding, I made the mistake of trying to write new if statements for each pressure level to indicate which sound to play. My partner quickly suggested that I simply add tone functions into the existing if statements which saved a lot of work. I will keep in mind going forward to look for ways to keep things concise for the sake of time but also for a more readable code.
Pressure Sensor with Buzzer Code
#define fsrpin A0
//Define variable to store sensor readings:
int fsrreading; //Variable to store FSR value
void setup() {
// Begin serial communication at a baud rate of 9600:
Serial.begin(9600);
}
void loop() {
// Read the FSR pin and store the output as fsrreading:
fsrreading = analogRead(fsrpin);
// Print the fsrreading in the serial monitor:
// Print the string "Analog reading = ".
Serial.print("Analog reading = "); // Print the fsrreading:
Serial.print(fsrreading); // We can set some threshholds to display how much pressure is roughly applied:
//tone function added to play a sound depending on pressure level
if (fsrreading < 10) {
Serial.println(" - No pressure");
} else if (fsrreading < 200) {
Serial.println(" - Light touch");
} else if (fsrreading < 500) {
Serial.println(" - Light squeeze");
tone(8, 300, 2000);
} else if (fsrreading < 800) {
Serial.println(" - Medium squeeze");
tone(8, 200, 2000);
} else {
Serial.println(" - Big squeeze");
tone(8, 100, 2000);
}
delay(500); //Delay 500 ms.
}
REFLECTION
This activity was very helpful in order to teach me the basics of arduino, sensors, and the processing language. Also, with an understanding of how to connect a circuit without a breadboard, the potential for the design of future projects has become much more broad.
Question 1: What did you intend to assemble in the recitation exercise? If your sensor/actuator combination were to be used for pragmatic purposes, who would use it, why would they use it, and how could it be used?
Answered in the GOAL section of each circuit
Question 2: Code is often compared to following a recipe or tutorial. Why do you think that is?
Code is comparable to following a tutorial because it is a specific step by step process read by the computer. The order of code matters as the computer must know everything in the correct order to produce the intended result.
Question 3: In The Language of New Media, Manovich describes the influence of computers on new media. In what ways do you believe the computer influences our human behaviors?
Our lives are a constant interaction with computers of many sorts. Notably, computers have influenced our desire to connect, create, and explore in new ways. Because of computers, innovation happens at such a quick pace and people are constantly finding unique and innovative ways to improve convenience and accessibility. The biggest difference in human behavior is that we now look to computers for almost all of our problems in order to find a quicker, better, or easier solution.
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