Arduino uno User Manual

if (this.connectionId < 0) {
throw "No serial device connected.";
}
chrome.serial.send(
this.connectionId,
this.stringToArrayBuffer(data),
function() {});
};
onReceive basically works like the sample listener we implemented in Exploring
the Chrome Serial API, on page 271. The only difference is that the new imple-
mentation looks for newline characters. Whenever it finds one, it passes the
current read buffer to the function that is listening for onReadLine events. Note
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 events.
For our purposes we don’t need a send method, but it doesn’t hurt to add it
for the sake of completeness. This way, you have a SerialDevice class that you
can use in many more projects.
Finally, we need our two helper methods for converting ArrayBuffer objects into
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 • 278
report erratum • discuss
www.it-ebooks.info

Arduino uno Specifications

General

Form factor	Arduino
Certification	RoHS, FC, CE
Processor model	-
Processor frequency	- MHz
Microcontroller model	ATmega328
Microcontroller frequency	16 MHz
DC input voltage	7-12 V
Operating voltage	5 V
DC current per I/O pin	40 mA
Flash memory	0.032 MB
Maximum internal memory	- GB
SRAM (Static Random Access Memory)	2 KB
EEPROM (Electrically Erasable Programmable Read-Only Memory)	1 KB
Wi-Fi	No
Number of analog I/O pins	6
Number of digital I/O pins	14

Weight and Dimensions

Board dimensions	53.4 x 68.6 mm