Adruino Serial Plotter

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About: I'm an Electronics Engineer who likes to make Doze Lamps, Lumen Powered Thingamajigs, Almighty Brainy Buttons, Tweeting Weather Stations and share them on Instructables.

The Arduino Serial Plotter function has been added to the Arduino IDE, allowing you to natively graph serial data from your Arduino to your computer in real time. If you’re tired of seeing your Arduino’s analog sensor input data pour onto your screen like The Matrix, this looks like a prettier way to visualize what’s going on. A Serial plotter is an offline tool allowing you too Visualize data and troubleshoot your code offline without having to use third-party services like Processing or Plotly. Since there is no official documentation on the Arduino website regarding the use & functionality of the Serial Plotter, I decided to documents its uses and features.

Features

  • Plotting of Multiple Graph
  • Offline
  • Auto-Resize Graph
  • Supports Negative Value graphs
  • Auto-scroll along X-axis
  • Different colors for each variable

Applications

  • Offline Data Visualization
  • Code Troubleshooting
  • Waveform Analysis

Parts Required

Arduino - AliExpress or
Arduino Starter Kit - AliExpress

Teacher Notes

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Step 1: Plotting a Graph

Now that you have installed the latest version of the Arduino IDE(1.6.7 or above) its time to understand how the Serial Plotter actually works. The Arduino Serial Plotter takes incoming serial data values over the USB connection and is able to graph the data along the X/Y axis, beyond just seeing numbers being spit out on to the Serial Monitor. The vertical Y-axis auto adjusts itself as the value of the output increases or decreases, and the X-axis is a fixed 500 point axis with each tick of the axis equal to an executed Serial.println() command. In other words the plot is updated along the X-axis every time the Serial.println() is updated with a new value.

Remember to set the Baud Rate of the Serial Plotter so that it matches that of the code.

Multiple Plots

When displaying multiple waveforms, every separate variable/value/parameter is displayed using a different colour like shown below.

Inorder to plot multiple variables or waveforms simultaneously a 'space' is printed between the two print statements.

Serial.print(temperature);
Serial.print(" ");
Serial.println(humidity);

OR

Serial.print(temperature);
Serial.print("\t");
Serial.println(humidity); 

In this case the values of the variables 'temperature & humidity will have separate waveforms plotted on the same graph simultaneously.

Step 2: Offline Data Visulization

I used the Arduino Serial Monitor in my Automatic Plant Watering System to visualize & plot Moisture Sensor Data.

The main purpose of having the Serial plotter is that you do not need to be connected to the Internet in-order to visualize the data from a sensor or your project. And hence for the purpose of Data Visualization the Serial plotter excels at its job.

Whether its a singular wave or a multiple plot graph the Serial Plotter auto-resizes itself and color codes each wave. In-order to test the Data Visualization function you can follow the following steps:

  1. Connect a couple of sensors to your Arduino
  2. Print the values of the sensors & Upload the code.
  3. Open the Serial Plotter.

I have used the Serial Plotter in my Tweeting Weather Station to visualize the reading of the various sensors on the Weather Station. The above waveforms show the plot of the Temperature(26°C) & Humidity(65%RH) readings of the SL-HS-220 sensor.

Step 3: Troubleshooting

One of the best uses of the Serial Plotter is to troubleshoot the code & circuit. Faulty connections or incorrect coding logic can sometimes return an undesired output. In such cases where there too many lines of code or too many wires to debug the Serial Plotter can show the exact point of error.

With the help of the Serial Plotter you can check if a sensors reading is incorrect or even if the sensor is not connected properly to the Arduino. The Serial Plotter will also help debugging code by displaying the values various conditional statements and variables or even the states of the pins of the Arduino.

A good example of would be troubleshooting a Obstacle Avoidance Robot. In this example the Blue waveform represents the Ultrasonic sensor and the Yellow and Red waveforms represent the left and right motors. As the distance between the obstacle & the robot decreases, the Blue waveform decreases. At a threshold value(minimum distance) of 10, the robot turns right hence the two motors have different value's;Right=50,Left=100. You can see the Red waveform decreasing and the Yellow waveform remaining constant speed which represents the right turn.

Troubleshooting whether a wire was not connected properly or a component was malfunctioning or your coding logic was incorrect would have cost you a lot of time. But with the help of the Serial Plotter the amount of time it takes to troubleshoot the problem can be significantly reduced by analyzing the waveforms.

Step 4: Function Generation & Analysis

With a basic programming sense and a couple of lines of code, the Arduino is able to act as a Function Generator. The Arduino is capable of producing Square,Triangular, Sine & Sawtooth waveforms. In previous versions of the Arduino IDE one could only observe the values of the type of waveform being produced in the Serial Monitor without any visualization. It would be time consuming to analyze the output solely on the basis of numerical value's; and this is the place where the Serial Plotter comes handy; in visualizing the waveforms being produced.

Function Generator.inoFunction Generator.ino

Step 5: Future Improvement & Additions

The Arduino IDE has for long needed the addition of the Serial Plotter. It has increased the functionality of the Arduino IDE but still lacks some features:

  • Autoscroll Toggle
  • Simultaneous use of Serial Plotter & Serial Monitor.
  • X-axis Scale/Time scale required.

As these features are added to the Arduino IDE, I will continue to make changes and add new steps to this Instructable.

Raspberry Pi Contest 2016

Participated in the
Raspberry Pi Contest 2016

Digital Life 101 Challenge

Participated in the
Digital Life 101 Challenge

2 People Made This Project!

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27 Discussions

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Vabrinnta

2 years ago

First of all thank you for showing how to use the plotter function.

I have one question:

Is it somehow possible to plot the data and simultaneously save the data with i.g. CoolTerm? If I try to do it, the Arduino sketch will give me an error telling me that the monitor can´t be opened while the plotter is open.

Thanks in advance.

Best regards

Florian

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JonathanrjpereiraVabrinnta

Reply 2 years ago

I am not familiar with CoolTerm. But in my experience if something is sharing the same serial port as the serial monitor/plotter while they are open could result in a similar error.
It could also be that your serial monitor is already opened & hence the plotter cannot be opened simultaneously.

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CaseyS2

Question 5 months ago on Step 5

Is there a way to reverse this?

Such as I want to make a data plotter using a small screen or LED matrix be the display for the plotter?

I was curious if there is an easy way to do this or if you kind of have to code the visualization from scratch?

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NuttyProfessor47

Question 11 months ago on Introduction

Thank you very much for showing how the plotter can be used. I cannot believe it's been added to the Arduino IDE with no guidance at all on how to use it. Surely the author knows? Anyway can the waveform be "locked", or in oscilloscope parlance, synchronised? Or, is there a way to get fewer cycles displayed and expanded across the window? I need to examine the phase relationship between two waveforms, and can't when they are scrolling rapidly left.

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JonathanrjpereiraNuttyProfessor47

Answer 11 months ago

As of now, there is no way to disable AutoScroll on the Serial Plotter.

Assuming you have two physical input signals, an XOR gate can be used to calculate the phase difference.

Otherwise try taking a screenshot. (Start+PrintScreen).

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Nurul HananiM

11 months ago

Hi there ! can i know how to save the data or graph collected from the seriel monitor/plotter?

1 reply
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JonathanrjpereiraNurul HananiM

Reply 11 months ago

I would employ one of these two methods:
1. Read the data onto a laptop/PC connected through the serial port & save that data into a CSV file. You can then plot that data using a simple Matplotlib script in Python.
2. Read & Save the data onto an SD card using an SD card module. You can then use the same python script to plot the CSV data.

I'm sure there are other methods too.

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stevew17

2 years ago

does anyone know where in the IDE does one adjust the Baud rate (I know how to set the baud rate in the code but I am referring to the serial plotter) ?? It shows a picture on one of the steps where it says your code and the serial plotter must be set at equal baud rates (and it shows a pic of the baud rate of 9600 and a scroll down) but it doesn't show how to actually adjust the baud rate on the serial plotter. I ASK this question because on several projects now I have been able to build and test many of these projects but could never get results plotted on the plotter.

1 reply
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Jonathanrjpereirastevew17

Reply 1 year ago

In the images/gifs in steps 4 & 5, at the bottom left handside corner, there is a drop down menu to set the Baud Rate of the Serial Plotter.

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paraklet

2 years ago

are these graphs vs time?

can I get a table with the variables value?

1 reply
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dasraiser

1 year ago

Hi, thank you for this, I've just started with the serial plot and just discovered you can

Serial.print(UpperLimit); //constant max X
Serial.print(" ");
Serial.print(LowerLimit);// constant min X
Serial.print(" ");
Serial.println(Value X);

this locks the graph and stops it from auto scaling :D

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acboother

3 years ago

I agree about the lack of plotting facilities. I made this https://www.instructables.com/id/Arduino-Developmen...

over three years ago to address that issue plus add in a lot of other visualisers which can all be used simultaneously. Still freely available to those who contact me for the link.

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zencuke

3 years ago

Thanks for this. Nice clear explanation of a great tool. I have just one question. You say "The main purpose of having the Serial plotter is that you do not need to be connected to the Internet in-order to visualize the data from a sensor or your project." It would never occur to me to connect to the internet for data visualization. For visualization I think Excel, Processing, writing my own plot code in Python, whatever. IDE plotting is mostly a better choice than those but none of them need the Internet. What Internet data visualization tool am I missing that is so popular that you just assume it?

2 replies
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Jonathanrjpereirazencuke

Reply 3 years ago

Assume a person(someone like me) who is not familiar with Processing or Interfacing an Arduino with Excel or has no experience with languages such as Python needs to visualize the data from his/her Arduino. The Serial Plotter is a useful tool too such a person. Since I had no knowledge regarding Processing,Python,etc I took too online(Internet based) open source data visualization platforms(Plotly, Sparkfun Data,etc) too visualize my data. These platforms are very easy to use if you have a wifi shield as you only need to copy & paste a few lines of code available in their documentation & user guides. Now considering the fact that this tutorial is made for newbies who do not possess a wifi shield and have basic coding skills; this Instructable is made to cater to their data visualization needs.

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zencukeJonathanrjpereira

Reply 3 years ago

I totally agree and I will be using this mode a lot even though I am not a newbie. Your tutorial will be a great help and thanks for writing it. I just don't understand what any of this this has to do with being connected to the Internet. Most of the other visualization tools don't need an Internet connection either. I use this mode mostly because it is the simplest visualization method for looking at Arduino generated data because it is built in to the IDE.

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KickolasNage

3 years ago

Have you found a way to plot more than two channels using Serial Plotter?