Arduino Nano 20KHz Pocket Sized Digital Oscilloscope.

Previously, I posted a tutorial on Raspberry Pi-Pico Oscilloscope. And that was a great success. Keeping portable options in mind, I found this pretty mini oscilloscope between thousands of pages of a Japanese website. We are using a mini-OLED 128X64 to display the signal waveform, Frequency, duty cycle. 4 tactile buttons are used to change the modes, Volts/Divisions, and time/Divisions. So, I tried this, and the results are here.

Note* This project is only for educational purposes and shows the capabilities of a 16Mhz 8-bit microcontroller board. This MCU Can support frequencies below 50KHz, so it can’t be applicable for commercial and professional uses. That way, the project can also be entitled POOR MAN OSCILLOSCOPE for me.

Supplies

Components used:

Arduino Nano
128X64 OLED display
100k,10k,820k,510k,12k resistors
100nf, 7pf, 1uf ceramic disc capacitors
Tactile switch x4
Breadboard
Connecting wires

Arduino Nano/Uno:

Both the boards have the same 8-bit Atmega328p microcontroller to use any of them. This tutorial uses I2C communication to print the readings on an OLED display. Our microcontroller has 6-channel 10-bit ADC, 13 digital I/O pins, and an 8Mhz internal clock.

That's why I tried the project on breadboard first. I want to know the plus/minus points of this oscilloscope. This project is sponsored By JLCPCB, Pcb, code and circuit diagram to this project is given below. Download all Gerber file from here and Quote for PCB on JLCPCB just in $2, On first sign-up from here you will get worth $30 coupons to order PCB.

For PC: https://jlcpcb.com/SSR

For mobile phone: http://m.jlcpcb.com/ssi

Features:

Single-channel -20Khz bandwidth
Onscreen- Volt/Div and Time/Div
Duty cycle monitoring
Small 0.96-inch I2C
AC/DC measurements option
Mode changing, Hold state features
Low battery consumption
Portable and pocket-sized

Display:

0.96-inch OLED display with I2C function comes with two different models, SSD1306 and SH1106, to change the code as per requirements. We have to uncomment which version of LCD we are using in this project.

Circuit Diagram:

Both given circuits are same, You can use any of them as reference.

Mode Selection

After making all the connections, this oscilloscope can be powered by a 5v @100mA power supply or 3.7 volt Battery. Significantly fewer external components are used in this project; also, it supports several actions. Here MODE button is to select the volt/div, time/div, AC/DC, and 180* wave settings.

Volt/division Selection:

After selecting the Mode, we can either increase the value or decrease per wave format. For Volts/divisions: This oscilloscope supports a division from 0.2volts to 50volts.

Time/division Selection:

For Time/Div: Code is modified to display small divisions in microseconds, 1.56 microseconds to 200milli-seconds.

Measurements:

I tried to hook up this oscilloscope directly with Step down transformer AC signal and here are the results:

With 50Hz Sine wave, 310 Hz sine wave

Rectangular, Triangular and Sawtooth:

Libraries Used:

OLED display SSD1306, SH1106 , Fix_fft and EEPROM libraries are available in Arduino Mange library section. From here you can download as per your needs.

Code:

Code is quite bit long, so we added comments on all lines so that you can understand this. Code version 1.1

Download all the material regarding this project from here.

Preview:

// Follow us on Hackster, Hackaday and the Instructables.
//Please First uncomment/comment the oled driver lines, which you are using
//Circuitkicker.com -- Sagar saini --sainisagar7294


#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
//#include <Adafruit_SH1106.h>            // https://github.com/wonho-maker/Adafruit_SH1106
#include <EEPROM.h>


#define SCREEN_WIDTH   128              // OLED display width
#define SCREEN_HEIGHT   64              // OLED display height
#define REC_LENG       200              // size of wave data buffer
#define DISP_LENG      100              // size of display data
#define MIN_TRIG_SWING   5              // minimum trigger swing.(Display "Unsync" if swing smaller than this value
#define DOTS_DIV        25


// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1              // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);   // device name is oled
//Adafruit_SH1106 oled(OLED_RESET);        // use this when SH1106


#define R_12k   4        //  12k ohm
#define R_820k  16       //  820k ohm  for AC low range
#define R_82k   17       //  82k omm for AC Hi range

PCB:

Download all the material regarding this project from here.

Gerber files

Circuit diagram

Arduino Code

Conclusion:

This oscilloscope is suitable for analyzing waveforms between 10Hz to 20Khz. That is precisely human hearing frequency. So, we can use this to measure audio signals, amplifier signals, and different Bluetooth signals. This oscilloscope should be a good try for them. Also, I think precision matters a lot in signals. If you want to go professional but cheaper, I would recommend DSO138. But this is about 4x the cost of this Arduino oscilloscope, but this one has an analog frequency range of 200khz.

In comparison with This DSO, I have An Article about Raspberry Pi- Pico Oscilloscope, which offers android application compatibility, 2-channel, and 200khz frequency range. See this PI-PICO Oscilloscope from here.

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For PC: https://jlcpcb.com/SSR

For mobile phone: http://m.jlcpcb.com/ssi

Updates:

We are trying to use a big touch TFT color screen with a high resolutions, So the project will be updated as soon as possible till then keep supporting us, we did not want any type of financial support, just follow us.