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.
1. Understanding DSO Components
- Power Button: Turns the DSO ON/OFF.
- Display Screen: Shows the waveform.
- Probe Inputs (CH1, CH2): Connect the oscilloscope probes here.
- Time/Div Knob: Adjusts the time scale (horizontal axis).
- Volts/Div Knob: Adjusts the voltage scale (vertical axis).
- Trigger Controls: Helps stabilize the waveform.
2. Connecting the Oscilloscope to Arduino
A. Connect the Probe Correctly
- Turn OFF the oscilloscope before connecting anything.
- Take one oscilloscope probe and connect:
- Probe Tip: To Arduino PWM Pin 9 (or any analog pin you are testing).
- Probe Ground (Clip): To Arduino GND (Ground).
- Power up the Arduino and DSO.
3. Configuring the Oscilloscope for Basic Signal Viewing
A. Set the Channel
- Press the CH1 button to activate Channel 1 (where we connected the probe).
- If using two probes, press CH2 for the second channel.
B. Adjust the Voltage Scale (Vertical Setting)
- Use the Volts/Div knob to set the voltage range.
- Start with 1V/div and increase if needed.
- For a 5V Arduino signal, set it around 2V/div for better viewing.
C. Adjust the Time Scale (Horizontal Setting)
- Use the Time/Div knob to set the time range.
- If measuring PWM signals (~500Hz), start with 1ms/div.
- If measuring fast signals (above 1kHz), use 100µs/div.
D. Set the Trigger for a Stable Display
- Press the Trigger Menu and set:
- Mode: Edge
- Source: CH1
- Slope: Rising Edge
- Level: Adjust until the waveform stabilizes
4. Running the Oscilloscope & Viewing the Waveform
- Press AUTOSET (if available) to let the DSO automatically adjust settings.
- If AUTOSET doesn’t work well, manually tweak Volts/Div and Time/Div.
- Observe the waveform:
- If using PWM output, you should see a square wave.
- If using an analog sensor, the waveform may look more irregular.
- Use Cursors or Measurements (if your DSO has them) to check signal values.
5. Capturing & Analyzing the Waveform
- If your oscilloscope has a Save function, take a screenshot of the waveform.
- Compare the output with the expected Arduino signal.
- Adjust your Arduino code if needed to modify the signal.
void setup() {
pinMode(9, OUTPUT);
}
void loop() {
for (int u = 0; u < 255; u++){
analogWrite(9, u);
delay(50);
}
}Video Demonstration
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));
Serial.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);
}