Week 9:Input Devices

This week describes my understanding of how to use Input Devices. It also includes how to generate an analog output (PWM) using pin 9, how to use an oscilloscope and multimeter for analysis, and how to integrate different sesnor with the microcontroller.

For More About group Assignment

Interpret a Signal

We generate an analog output (PWM) using pin 9. A LED is connected to see the signal effect, and the oscilloscope and multimeter are used for analysis.

                void setup() {
                pinMode(9, OUTPUT);
                }

                void loop() {
                for (int u = 0; u < 255; u++){
                    analogWrite(9, u);
                    delay(50);
                }
                }
            

Video Demonstration

For Group Assignment Refer here

Joystick Module

The Joystick Module consists of two potentiometers, each controlling an axis (X and Y).

Reading Joystick Module

Connect the joystick to Arduino: A0 and A1 for analog readings, pin 2 for the button.

                    int x_Pin = A0;
                    int y_Pin = A1;
                    int button_Pin = 2;

                    void setup(){
                        Serial.begin(9600);
                        pinMode(button_Pin, INPUT_PULLUP);
                   }

                    void loop(){
                        Serial.print("X: "); Serial.print(analogRead(x_Pin));
                        erial.print("\tY: "); Serial.print(analogRead(y_Pin));
                        Serial.print("\tButton: "); Serial.println(digitalRead(button_Pin));
                    delay(100);
                    }
                

Joystick Axis Values

Axis X	Axis Y
Up	1023	527
Down	0	527
Right	512	1023
Left	512	0
Center	512	527

Video Demonstration

Temperature Sensor LM35

The LM35 is an analog temperature sensor with an output range of 0V to 1.5V.

                float temp = 0.0;
                int temp_Pin = 0;

                void setup(){
                    Serial.begin(9600);
                }
                void loop(){
                    temp = analogRead(temp_Pin);
                    Serial.print("temperature: ");
                    Serial.println(temp);
                    delay(100);
                }
            

Converting to Celsius

float temp_C = (5.0 * temp * 100.0) / 1024.0;

Ultrasonic Sensor HC-SR04

The HC-SR04 sensor calculates distance using ultrasonic waves.

            const int Trig = 2;
            const int Echo = 3;
            float tim = 0.0;
            float dist = 0.0;

            void setup(){
                Serial.begin(9600);
                pinMode(Trig, OUTPUT);
                pinMode(Echo, INPUT);
                digitalWrite(Trig, LOW);
            }

            void loop(){
                digitalWrite(Trig, HIGH);
                delayMicroseconds(10);
                digitalWrite(Trig, LOW);
                tim = pulseIn(Echo, HIGH);
                dist = tim / 59.0;
                Serial.print("Distance: ");
                Serial.print(dist);
                Serial.println(" cm");
                delay(100);
            }
        
        

Lets get into actual Work

For this week we have to do a board attached with Microcontroller and then work on the

As we have worked on the previous weeks for PCB Design and Electronics Production. we are gonna repeat the same process for the Board production

KiCAD Works

Initially we're setting up the process for the Design as we're gonna design the product for Joystick Input, SDA, SCL ports and then Servomotor ports

Schematic Design

Initially designed up the Kicad Schematic for the Board that we are gonna design

PCB Design

Now we gonna change that into PCB design using PCB Editor

PCB Milling

After Designing the Board exported it as nc file from the MoDS CE and imported it to Wegster CNC for milling and afterwards get that final Product is

Version 1 & Version 2 of the Board

The Problem is due to the form of greenish layer on the Coppper Board and the other one is well cleaned and secured with mineral oil after fabrication

Blunders happened during making Soldering

Intially I have soldered try to turn board it doesn't show any output and then I came to know the solder trace for the GND wasn't done at best

Making things ready for showing output

Now we get the solder and make up the Board and next we are gonna add the joystick to our microcontroller and afterwards showing the Graph out in Serial Plotter in arduino

Joystick Interface Code Explanation

            #define VRX_PIN 2   // A0
            #define VRY_PIN 3   // A1
            #define SW_PIN  0   // Digital button

            void setup() {
                Serial.begin(115200);
                pinMode(SW_PIN, INPUT_PULLUP); // Joystick button is active LOW
            }

            void loop() {
                int xValue = analogRead(VRX_PIN);
                int yValue = analogRead(VRY_PIN);
                int swState = digitalRead(SW_PIN);

            // Format for Serial Plotter: label:value, label:value
                Serial.print("X:");
                Serial.print(xValue);
                Serial.print(",Y:");
                Serial.print(yValue);
                Serial.print(",SW:");
                Serial.println(swState == LOW ? 0 : 4095); // show pressed/released as 0 or 4095

                delay(50); // smoother graph
            }
        
        

Pin Definitions

• #define VRX_PIN 2: Assigns pin 2 to read X-axis analog values.
• #define VRY_PIN 3: Assigns pin 3 to read Y-axis analog values.
• #define SW_PIN 0: Assigns pin 0 to read joystick button state.

Setup Function

• Serial.begin(115200);: Begins serial communication for plotting or debugging.
• pinMode(SW_PIN, INPUT_PULLUP);: Sets the button pin as input with an internal pull-up resistor.

Loop Function

• int xValue = analogRead(VRX_PIN);: Reads and stores X-axis value.
• int yValue = analogRead(VRY_PIN);: Reads and stores Y-axis value.
• int swState = digitalRead(SW_PIN);: Reads the joystick button state (pressed/released).

Serial Output Formatting

• Serial.print("X:"): Labels the X value for plotting.
• Serial.print(xValue): Prints the X-axis value.
• Serial.print(",Y:"): Adds Y-axis label.
• Serial.print(yValue): Prints Y-axis value.
• Serial.print(",SW:"): Adds switch label.
• Serial.println(swState == LOW ? 0 : 4095);: Converts button state to 0 or 4095 for Serial Plotter graph scaling.

Delay

delay(50);: Adds a 50ms delay for smoother plotting without excessive data refresh.

Refer for PCB Production

Hero Shot

Learning Summary

• Learned about the basics of Arduino and its components.
• Understood about the Xiao - Seeed Studio Esp32C3
• Learned how to use the LiquidCrystal library to control an LCD screen.
• Implemented a simple timer using the LCD screen.
• Interfacing Joystick with actually fabricated PCB Board

Download the Files

Joystick Interface

waveform_analysis

PCB Design Files

That’s all for now!