Introduction When writing Arduino programs you sometimes need to receive some commands or data from serial line. Relying on the (poorly written) Arduino stream parsing routines is not good. The function terminates if it times out (see setTimeout()). Not only are they blocking, but often they just don't work right. In the case of Raspberry Pi, the serial port (on my Arduino) is located at '/dev/ttyACM0'. These three simple lines read a single row of data from the serial port. Instead you should be reading the serial properly, taking account of line endings, and then converting the string you have read into a number using the likes of atoi().
), or perhaps a different address completely. Explains how to reliably read data or commands from serial line in Arduino without blocking the loop.

In this example we will use analog pin 0 to obtain a value and send it via the com port (USB) , we will read this with a C# app and display the value in a progress bar and label. Arduino Serial readStringUntil Function reads the serial port into the string variable, until it receive the terminating character. You may also find yours there, or at an integer increment (ttyACM1, ttyACM2, etc. The Arduino programming language Reference, organized into Functions, ... reads characters from the serial buffer into a String. Check your Arduino IDE serial port for the exact location. The entire String read from the serial buffer, up to the terminator character.

How to use Arduino Serial Read ? By default the readStringUntil function wait for terminating character or timeout to complete. End of line should be signaled by a decimal 10, aka LF(Line Feed) character. while (file.available() && file.peek() != 10) // peek returns the next character without incrementing the read index file.read(); So what you do is keep reading until you encounter LF or end of file, which then is the entire line you want to read. Tutorial on reading serial: by iainhendry71 January 23, 2014. Arduino Serial read command is used for reading any data available at the Serial Port. Arduino Serial Read String Until Function – Serial.readStringUntil. So, now we have got the Serial Port on Arduino UNO which we know are at pin # 0 and pin # 1, now in the next part, we are gonna have a look at How to use Arduino Serial Read and get data from this Serial Port. Reading Serial data from an Arduino using C#.