Arduino Uno Quick Start Manual page 290

if (this.connectionId < 0) {
throw "No serial device
}
chrome.serial.send(
this.connectionId,
this.stringToArrayBuffer(data),
function() {});
};
onReceive basically works like the sample listener we implemented in
the Chrome Serial API, on page
mentation looks for newline characters. Whenever it finds one, it passes the
current read buffer to the function that is listening for
that more than one line can be transmitted in a single data chunk. Also note
that onReceive checks whether it got data from the correct serial port.
The onReceiveError method also makes sure first that it got error information
for the correct connection. In this case, it dispatches the event to the function
that is listening for onError
For our purposes we don t need a
for the sake of completeness. This way, you have a
can use in many more projects.
Finally, we need our two helper methods for converting
strings and vice versa:
ChromeApps/SerialDevice/js/serial_device.js
SerialDevice.prototype.arrayBufferToString = function(buf) {
var bufView = new Uint8Array(buf);
var encodedString = String.fromCharCode.apply(null, bufView);
return decodeURIComponent(escape(encodedString));
};
SerialDevice.prototype.stringToArrayBuffer = function(str) {
var encodedString = unescape(encodeURIComponent(str));
var bytes = new Uint8Array(encodedString.length);
for (var i = 0; i < encodedString.length; ++i) {
bytes[i] = encodedString.charCodeAt(i);
}
return bytes.buffer;
};
That s it! We now have a generic class for communicating with serial devices
from a Chrome app. Let s use it right away and write a small demo application.
This demo will be the simplest serial monitor possible. It will permanently
read data from a serial port and display it in an HTML page. The HTML page
looks as follows:
Appendix 4. Controlling the Arduino with a Browser
connected.";
271. The only difference is that the new imple-
events.
send method, but it doesn t hurt to add it
www.it-ebooks.info
Exploring
onReadLine events. Note
SerialDevice class that you
ArrayBuffer objects into
278
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