Oscilloscope is a device that allows us to see graphically the electrical signal.
If you want a cheap oscilloscope to learn what it is or to play with, follow the steps below:
Step 1: Have an Arduino Uno
The price of Arduino Uno is around $ 20 in internet stores.
Step 2: Install the Arduino IDE and TimerOne.h Library
- First, if you do not already have the Arduino IDE installed, install it from the site Arduino: click here
- Install the "TimerOne.h" library for the Arduino IDE, following the steps bellow
- In the Arduino program click on "Sketch" (see the picture)
- "Include Library ..."
- "Manage Libraries ..."
- On the line "Type: 'all' Topic: 'all'" has a blank search field , type "TimerOne".
- (Information about the library will appear )
- click over that text and the "Install" button will appear.
- click "Install"
- Restart the program
Step 3: Download Arduino Program and Upload It to Arduino
- Download and unzip the Arduino program from this link: (oscilloscope_arduino.ino)
- Connect the Arduino to the computer via USB port
- Run the Arduino IDE;
- Open the downloaded program "oscilloscope_arduino.ino"
- Adjust the COM port correctly (see picture)
- Upload the program to Arduino.
Step 4: Download the Oscilloscope Processing Program
Step 5: Configure Serial Port to Connect Oscilloscope Program With Arduino
- You already have the oscilloscope program running and the Arduino connected to the computer by USB port. Now you have to connect to each other by "serial".
- In the "Configurar a serial" (Configure the Serial) box, click "Serial" until the COM where the Arduino is connected appears.(if it did not appear, click " * " to update)
- Click "off" to switch to "on"
If everything is correct, the oscilloscope will do a first reading showing the noises because the channels A0 (ch-0), A1 (ch-1), A2 (ch-2) and A3 (ch-3) are not connected to any signal.
- In the "Amostragem" (Sampling) box, click "varias" (various) so that the reading is continuous.
Step 6: Connect the Output (~10) to Input (A0) and (~9) to (A1)
- With wires connect the Arduino's digital output (~10) to analog input (A0) and digital output (~9) to input (A1).
You will see appear a signal like the picture.
The out (~9) and (~10) are generated by the "Ger.Sinal" box:
(~9) is PWM of 10Hz (T = 100ms) with 25% ON.
(~10) is a square of period 2T (200ms)
- You can adjust the values on that box dragging the edge or clicking around the control.
Step 7: Tips
- Click "Trigger" at the Ch-0 (red) to stabilish the signals.
- To not read the signals of Ch-2 and Ch-3, click on the names "Ch-2" and Ch-3 ".
- To see the XY (Lissajous figures), click on the name "XYZ"
- To detect the frequencies, click on "detect freq."
- To measure voltage and time/frequency, click on "medir" (measure) of the desired channel then click on a point on the graph and drag to the other desired point.
- To change the dial control value click between vertical lines or drag the edge indicated by the triangles. (see picture)
- There is so much more! Explore!
Step 8: Aplication: Detecting Flash Frequency
You can find out the frequency that the flashlight is blinking using a LDR and a resistor (see the picture)
Step 9: Application: Detecting RPM of Fan
To find out the RPM of a fan use the circuit with LDR, resistor and a flashlight (not blinking).
Using the frequency value shown by the oscilloscope, apply the formula of the picture.
Step 10: Application: Analysing the Remote Control Signal
You can see the IR signal from remote control using the phototransistor TIL78.
Make the circuit of the picture, then follow the steps bellow:
- Adjust "dt" to 2ms (see all signal) or 100us (see details)
- Turn ch-0 trigger ON
- Increase level of trigger tension
- Click "UMA" (one): oscilloscope will stay waitting for the signal
- Press any remote control key directing it to TIL-78
- Analyse the graphic
Step 11: Application: Testing Components or Devices
We can use the oscilloscope to test electronic components or devices.
In this example we will test the little joystick for Arduino.
- Make the circuit shown in the picture.
- Connect the oscilloscope program to Arduino (configuring the Serial Port box)
- Click on "fluxo" (flow) so the Arduino sends each point right after reading.
- Adjust "dt" to 100ms to have a slow reading.
- Turn off the "ch-3" clicking over the name
- Adjust "v/div" to 5 (pressing the "shift" key to adjust all channels simultaneously)
- Change the ch-0 to up, moving the little left triangle (pressing the "shift" key)
- Turn on the XYZ channel and drag the "v/div", adjusting it to fill the free space.
- Move the joystick to all directions and press the button some times.
- See the curves.
Step 12: Measure Resistors and Capacitors
The "medir res./cap." (measure res./cap.) box is for measuring values of resistors and capacitors, but it will only work if you make the circuit of the picture.
That function has the hability to discover by itself if the component connected is a capacitor or a resistor, and to choose the better result using 3 scales (low, middle or high values)
Step 13: Do You Want More Fun?
You can download the entire project directly from the GitHub site clicking here
Watch the video on Youtube (turn on closecaption and translate to english!)
Please, let me know if you liked that project or if you had any trouble to follow the steps.
I will apreciate any help to develop that project. Programmers, users, curious, dreammers, etc.., will be welcome! ;)