I would like to read from the USB serial port from time to time in a loop. I can open the port and read data with: import serial ser = serial.Serial('/dev/ttyACM0', 9600) while 1: ser.readline() An Arduino Uno is connected to the USB port of the RPi. The Arduino acts as a sensor and it will constantly produce readings. I need some help in adding timing features to the above code. I want to open the port and read from it for a certain period of time. After that period of time, the port closes and the received data will be analysed. After a pause of several minutes, the port will reopen and the RPi will read data from it again.

Import serial. As we will usually only need the Serial class, you could also use from serial import Serial if you prefer. #! Bellcore Manual Of Construction Procedures Manual. /usr/bin/env python import serial. A note on readline(). The example thermometer always returns exactly eight bytes, and so ser.read(size=8) is a good way of reading it. However, in the more general case,. Mar 28, 2010. InWaiting() >0: out += ser.read(1) if out!= ': print '>>' + out. NOTE for Python 3 users: The code above has been written for Python 2 and I'm no more able to test RS232 connections with Python 3. As some users commented below the raw_input() function has been removed so you should just use the new.

This continues in a loop. Any help is much appreciated. All you would need to add, aside from closing the port when you're done;), is import time and then use: import serial, time ser = serial.Serial('/dev/ttyACM0', 9600) while 1: serial_line = ser.readline() print(serial_line) # If using Python 2.x use: print serial_line # Do some other work on the data time.sleep(300) # sleep 5 minutes # Loop restarts once the sleep is finished ser.close() # Only executes once the loop exits I don't know if pySerial is buffered (data sent while sleeping is stored or simply dropped), but I usually prefer to use a generator, if you don't explicitly need to wait. They seem a bit more flexible (in my opinion): def serial_data(port, baudrate) ser = serial.Serial(port, baudrate) while True: yield ser.readline() ser.close() for line in serial_data('/dev/ttyACM0', 9600): [.transform data.] You might also be able to use the with syntax instead of the while, but I'm not too sure how that'd work with pySerial. I was just editing my comment to clarify, but locked after 5 minutes:/ The ser.close() never runs until the while loop is done (which doesn't really ever occur since it's while 1/ while true), so the serial port isn't actually closed between readline() calls. Since simply having a pySerial port open isn't blocking, that shouldn't be an issue.

If the while loop only ran x number of times, and then you wanted to work on that the port again, just leave the port open until done (move ser. Profusion Eeg Software Download. close() after all code that interacts with the port). – Apr 30 '14 at 19:01.