#746 Serial Control

Using serial commands to control and query information from an Arduino.

Notes

This is a simple Arduino sketch that responds to serial control. As well as providing a simple demonstration of Arduino serial coding, I made this sketch so that I could use the Uno as an intelligent responder for testing client-side serial code.

Form more information on serial communications, see Arduino Cookbook: 4. Serial Communications

Code

The SerialControl.ino sketch listens for commands on the serial port and then responds accordingly.

Currently, it supports the following commands:

• d : show system information
• i : generate a random 8-bit integer
• s<length> : generate a random string of specified length
• t : toggle the LED on pin 13
• ? : show this message

A blank line will follow the output of all commands. This indicator may be used for client-side flow control if required.

Using the Arduino IDE

The script can be compiled and uploaded from the IDE, and used with the built-in serial monitor set for 115200 baud:

Using Screen

I’m using macOS, so (as with Linux) the most handy console utility is screen.

The Arduino is showing up as a character and TTY device with ID 2430:

$ ls -1 /dev/*serial*
/dev/cu.usbserial-2430
/dev/cu.wchusbserial2430
/dev/tty.usbserial-2430
/dev/tty.wchusbserial2430

For simple character interaction, any of these devices with work, but cu devices are preferred. For example:

screen /dev/cu.usbserial-2430 115200

Credits and References

• Arduino reference: Serial
• Arduino Cookbook: 4. Serial Communications
• screen notes