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УДК-62
BUILDING AN ARDUINO-POWERED OSCILLOSCOPE FOR MEASURING ELECTRICAL SIGNALS
Muhiyeva Guncha Bayramdurdyyevna
4th year student of the Faculty of "Cyberphysical Systems", Oguzhan Engineering Technologies University of Turkmenistan Ashgabat, Turkmenistan
An oscilloscope is an essential tool for engineers and hobbyists alike, allowing for the visualization and analysis of electrical signals in the form of waveforms. Typically, oscilloscopes are expensive and can be overkill for simple tasks or DIY projects. However, with the rise of affordable microcontrollers like Arduino, it is now possible to build a functional, albeit basic, oscilloscope that can measure and display electrical signals on a screen. This project allows enthusiasts and learners to understand both the functionality of an oscilloscope and the power of Arduino as a tool for signal processing.
What You Will Need:
• Arduino Board (e.g., Arduino Uno or Nano)
• LCD or OLED Display (to visualize the waveform)
• Resistors, Capacitors, and other basic components (for signal conditioning)
• Breadboard and jumper wires
• Input Signal Source (e.g., function generator or other signal sources)
• Potentiometer (for adjusting the scale or time base)
• Analog to Digital Converter (ADC) (on the Arduino)
• Optional: External Operational Amplifiers (for signal amplification)
Understanding the Basics:
Before diving into the construction, it is important to understand a few basic principles:
• Oscilloscope Functionality: An oscilloscope works by sampling an input signal and then plotting it as a function of time. The signal is typically displayed on a graph with time on the x-axis and voltage on the y-axis. In more advanced oscilloscopes, additional features like triggering, frequency analysis, and waveform storage are included.
• Arduino ADC: The Arduino board has an Analog to Digital Converter (ADC) that can convert the input voltage signal into a digital value. This value can then be processed and used to recreate the signal waveform on the display.
• Sampling Rate: The Arduino is not a dedicated oscilloscope, so the sampling rate (how often the Arduino reads the input signal) will be limited.
The speed of the Arduino's ADC and how frequently you sample the signal will impact the resolution and smoothness of the waveform.
Step-by-Step Guide to Building an Arduino Oscilloscope:
1. Setting Up the Arduino:
The first step is to set up the Arduino environment. If you are using an Arduino Uno or Nano, ensure that you have the Arduino IDE installed on your computer and that your board is correctly connected.
2. Connecting the Display:
For this project, you can use an LCD or OLED display. An OLED screen is preferred due to its clearer display and lower power consumption. Connect the display to the Arduino using I2C (Inter-Integrated Circuit) communication, which simplifies the wiring process.
For an OLED display, connect the SDA and SCL pins to the corresponding Arduino pins (A4 for SDA and A5 for SCL on the Arduino Uno). Also, connect VCC to 5 V and GND to GND.
3. Signal Input:
To measure electrical signals, you'll need to provide an input signal to the Arduino. This can be done by using a function generator or simply connecting any known signal source (e.g., the output of a signal generator, an audio signal, or an AC voltage source). Make sure the voltage of the signal is within the Arduino's ADC input range (0-5V for a standard Arduino).
You may need to use a resistor divider circuit or an operational amplifier (op-amp) to scale the input signal to match the Arduino's ADC input range.
4. Writing the Code:
The Arduino code will be responsible for reading the input signal, processing the data, and displaying the waveform on the screen.
#include <Wire.h> #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h>
// OLED display settings #define SCREEN_WIDTH 128 #define SCREEN_HEIGHT 64 #define OLED RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
const int inputPin = A0; // Pin where the signal is connected
const int sampleRate = 500; // Samples per second (adjust as needed)
void setup() {
Serial.begin(9600);
display.begin(SSD1306_SWITCHCAPVCC, 0x3C); display.clearDisplay();}
void loop() {
int signalValue = analogRead(inputPin); // Read input signal
int mappedValue = map(signalValue, 0, 1023, 0, SCREEN_HEIGHT); // Map to display height
// Clear the display and draw the waveform display.clearDisplay();
display.drawLine(0, SCREEN_HEIGHT / 2, 127, SCREEN_HEIGHT / 2); // Draw baseline
display.drawLine(0, mappedValue, 127, mappedValue); // Draw waveform
display.display();
delay(1000 / sampleRate); // Wait for the next sample}
In this basic code, the Arduino reads the input signal from the analog pin, maps it to the screen height, and draws a line on the OLED display to represent the signal. You can adjust the sample rate and modify the code to improve the display or enhance functionality (e.g., adding controls to zoom in/out or change the time base).
5. Scaling and Adjustments:
Depending on the input signal, you may want to adjust the scaling and the display settings. For example, you could add a potentiometer to adjust the vertical scale (amplitude) or a second one for adjusting the horizontal scale (time base). You can connect the potentiometer to one of the Arduino's analog input pins and modify the code accordingly to scale the signal on the screen.
6. Displaying the Waveform:
Once the system is running, the Arduino will continuously sample the input signal and update the display. You should be able to see the waveform of the signal on the OLED screen, with real-time updates reflecting any changes in the input signal.
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7. Enhancing the Oscilloscope:
While this basic oscilloscope will work for simple signals, it can be expanded with more advanced features. You could add a trigger feature to stabilize periodic signals or implement an adjustable time base for better visualization of slower or faster signals. You can also increase the resolution of the waveform by improving the signal processing or using an external ADC with a higher resolution.
Conclusion:
Building an Arduino-powered oscilloscope is a rewarding project that allows you to explore both the fundamentals of signal measurement and the capabilities of the Arduino platform. While it may not match the performance of professional oscilloscopes, it provides an excellent introduction to electrical signal processing, microcontroller programming, and display technology. By experimenting with this basic oscilloscope, you can deepen your understanding of electronics and explore new ways to measure and analyze electrical signals in various projects.