Question

I am trying to figure out how I would go about taking serial information from an Arduino which controls a Javascript browser extension I have running in an open browser locally on a computer. It would seem that I would need some sort of middleman to internalize the serial readings and pass them to the browser (to activate the functions I have coded). Python? Any answers, help, and reference is greatly appreciated.

Answer 1

A very simple http server in python would look like this

from BaseHTTPServer import BaseHTTPRequestHandler,HTTPServer

class MyServer(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200, 'OK')
        self.send_header('Content-type', 'text/html')
        self.end_headers()
        self.wfile.write( "hello" )

HTTPServer(('', 8888), MyServer).serve_forever()

in the do_Get method you can add the code necessary to access your arduino program

...
ser = serial.Serial('/dev/tty.usbserial', 9600)
ser.write('5')
ser.readline()
...

another option would be coding this in ruby by using webrick as the webserver part

require "serialport.so"
require 'webrick';

SERIALPORT="/dev/ttyUSB0"

s =  HTTPServer.new( :Port => 2000 )

class DemoServlet < HTTPServlet::AbstractServlet
    def getValue()
        begin
            sp = SerialPort.new( SERIALPORT, 9600, 8, 1, SerialPort::NONE)
            sp.read_timeout = 500
            sp.write( "... whatever you like to send to your arduino" )
            body = sp.readline()
            sp.close
            return body
        rescue
            puts "cant open serial port"
        end
    end

    def do_GET( req, res )

        body = "--.--"
        body = getValue()

        res.body = body
        res['Content-Type'] = "text/plain"
    end
end
s.mount( "/test", DemoServlet )
trap("INT"){ s.shutdown }
s.start

a third option would be using an ethernet-shield on the arduino and skipping the proxy code completely