Summary of Sending Data From Arduino to Python Via USB
This article guides users on acquiring data from an Arduino UNO via USB and storing it in a text file for plotting using Python 3. It covers writing Arduino code to send analog readings, identifying the correct serial port in the Arduino IDE, and developing a Python script with Pyserial to receive, clean, and save the data. The process concludes by using NumPy and Matplotlib to visualize the stored information.
Parts used in the Sending Data From Arduino to Python Via USB project:
- Arduino UNO
- USB connection
- Python 3
- Arduino IDE
- Pyserial module
- Numpy library
- Matplotlib library
For several projects you might want to acquire some data from an Arduino board. There are several options and the one that I chose here uses the USB connection. I will explain how to store your data in a text file in order to plot it.
I will use Python 3, the Arduino IDE and an Arduino UNO. (I’m working on Linux but I think it should be the same procedure under macOS and Windows.)
Step 1: The Arduino Code
The Arduino will send the data onto the serial connection with the computer as you would the Arduino to send data to the Serial Monitor. So for example you can use the following code. The Arduino takes measures on the A0 analog pin. That’s pretty straight forward !
You can download the Arduino code on My website.
Step 2: Choosing the Proper Port
Open the Arduino IDE and try to upload the code you just downloaded. If it worked, copy the port name in the bottom right of the window.
Step 3: The Python Code : Receiving Data
Now we want to receive the data sent by the Arduino with Python (Python3). Therefore we need to install Pyserial.
You can download the Python program on my website
First we import the module serial
Then we try to open a communication; if it’s not possible we print an error.
If you want to change the baudrate it is actually possible like following but make sure it is the same as the one used in the Arduino IDE!
arduino = serial.Serial("/dev/ttyACMO",timeout=1, baudrate=whateverbaudrateyouwant)
Then in the while loop we receive the data. By choosing count<3 we will receive 3 values.
If you just want to print the data without storing it you could use an infinite loop :
while True: print(str(arduino.readline())
But as you can see on the second image the data presents some defects you don’t want to see..
Step 4: Cleaning Up the Data and Storing It in a Textfile
I’ve programmed 2 function allowing me to clean up the rawdata and then writing it in a text file.
I then use numpy.loadtxt with delimiter set on ‘;’ and matplotlib to plot the data.
That’s it ! I hope you found this Instructable interresting and useful.
Download link : As said before all the codes are freely available on my website.
Source: Sending Data From Arduino to Python Via USB
- How do I store data from an Arduino board?
You can store the data in a text file by using Python functions to clean up raw data and write it to a file before plotting. - What hardware is required for this project?
The project uses an Arduino UNO connected to a computer via a USB connection. - Can I use macOS or Windows for this procedure?
Yes, although the author works on Linux, the procedure should be the same under macOS and Windows. - Which Python module is needed to receive data?
You need to install the Pyserial module to receive data sent by the Arduino with Python 3. - How do I ensure the baudrate matches between Arduino and Python?
You must set the baudrate in the Python serial configuration to be exactly the same as the one used in the Arduino IDE. - What tools are used to plot the final data?
The article uses numpy.loadtxt to load the data and matplotlib to plot it. - Where can I download the provided codes?
All codes mentioned in the article are freely available on the author's website. - How does the Arduino send data to the computer?
The Arduino sends data onto the serial connection just like it would send data to the Serial Monitor.
