changed node.js hid example to be more user friendly

examples/device/hid_generic_inout/hid_test.js

@@ -1,22 +1,67 @@
+// IMPORTANT: install dependency via 'npm i node-hid' in the same location as the script
+// If the install fails on windows you may need to run 'npm i -g windows-build-tools' first to be able to compile native code needed for this library
+
 var HID = require('node-hid');
+var os = require('os')
+
+var isWin = (os.platform() === 'win32');
 var devices = HID.devices();
-var deviceInfo = devices.find( function(d) {
-    var isNRF = d.vendorId===0Xcafe && d.productId===0X4004;
-    return isNRF;
-});
+
+// choose either of the following supported devices:
+// Metro_nRF52840, Feather_nRF52840
+
+var deviceInfo = devices.find(Feather_nRF52840);
 var reportLen = 64;
+
+var message = "Hello World!"
+
+// Turn our string into an array of integers e.g. 'ascii codes', though charCodeAt spits out UTF-16
+// This means if you have characters in your string that are not Latin-1 you will have to add additional logic for character codes above 255
+var messageBuffer = Array.from(message, function(c){return c.charCodeAt(0)});
+
+// Windows wants you to prepend a 0 to whatever you send
+if(isWin){
+	messageBuffer.unshift(0)
+}
+
+// Some OSes expect that you always send a buffer that equals your report length
+// So lets fill up the rest of the buffer with zeros
+var paddingBuf = Array(reportLen-messageBuffer.length);
+paddingBuf.fill(0)
+messageBuffer = messageBuffer.concat(paddingBuf)
+
+// check if we actually found a device and if so send our messageBuffer to it
 if( deviceInfo ) {
 	console.log(deviceInfo)
 	var device = new HID.HID( deviceInfo.path );
-	device.on("data", function(data) { console.log(data.toString('hex')); });
 
+	// register an event listener for data coming from the device
+	device.on("data", function(data) {
+		// Print what we get from the device
+		console.log(data.toString('ascii'));
+	});
+
+	// the same for any error that occur
 	device.on("error", function(err) {console.log(err)});
 
+	// send our message to the device every 500ms
 	setInterval(function () {
-		var buf = Array(reportLen);
-		for( var i=0; i<buf.length; i++) {
-			buf[i] = 0x30 + i; // 0x30 = '0'
-		}
-		device.write(buf);
+		device.write(messageBuffer);
 	},500)
 }
+
+
+
+
+function Feather_nRF52840(d) {
+    return isDevice(0X239A,0X8029,d)
+}
+
+function Metro_nRF52840(d) {
+    return isDevice(0X239A,0X803F,d)
+}
+
+
+function isDevice(vid,pid,d){
+	return d.vendorId==vid && d.productId==pid;
+}