Firmata protocol and Node.js

This example shows the basic way to connect Arduino and Node.js through serial port (USB).

To install firmata run (note the -g option: the package is installed globally):

npm install firmata -g

Upload Firmata to Arduino

Use the StandardFirmata example. On Arduino IDE, select (macOS): File > Examples > Firmata > StandardFirmata. Assuming the USB is plugged, select: Sketch > Upload.

Running with REPL

REPL - read, eval and print loop is a interactive form to excercise with programming languages and environments. Firmata ships with this feature. Running firmata on the terminal, it will ask where the Arduino is connected to. In this case is /dev/cu.usbmodem1411

$ firmata
Enter USB Port and press enter:
/dev/cu.usbmodem1411
Successfully Connected to /dev/cu.usbmodem1411

Then, you're connected and with a variable named 'board' ready to use. Set the pin mode for pin 13 as output and 0 state (0 = LOW, 1 = HIGH).

$ board.pinMode(13, board.MODES.OUTPUT)
$ board.digitalWrite(13, 0)

Now, if the LED is connected to the digital 13, set it on:

$ board.digitalWrite(13, 1)

Running indefinitely

Running as standalone, just type:

node main.js

Inspect the main.js file: it also connects via /dev/cu.usbmodem1411 and sets a blinking LED (1 second) on digital pin 13 (output).

External

• https://github.com/firmata/firmata.js

License

MIT