Categories
Coding Internet of Things Python Software Uncategorized

Arduino Serial to Websocket in Python

What if we would like to publish data transmitted over RS232 Serial from an embedded Arduino device to a WebSocket browser client?

When prototyping a cable serial connection is very convenient as RF or networking modules may not yet be implemented. How do we get serial data to provision a cloud API service or web browser interface?

We can achieve this easily with Python and PySerial library:

#!/usr/bin/python

import serial
import asyncio
import datetime
import random
import websockets

ser = serial.Serial(
port='/dev/ttyUSB0',\
baudrate=115200,\
parity=serial.PARITY_NONE,\
stopbits=serial.STOPBITS_ONE,\
bytesize=serial.EIGHTBITS,\
timeout=0)

print("connected to: " + ser.portstr)


async def tx(websocket, path):
    line = []
    while True:
        for i in ser.read():
            c = chr(i)
            line.append(c)
            if c == '\n':
                print(''.join(line))
                await websocket.send(''.join(line))
                line = []
                break

start_server = websockets.serve(tx, "127.0.0.1", 5678)

asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

ser.close()

Here is a more detailed example of reading serial port data in C language on Linux Platform –

https://blog.mbedded.ninja/programming/operating-systems/linux/linux-serial-ports-using-c-cpp/