Using two BLE modules, have a master BLE repeatedly scan, connect, and disconnect from a BLE acting as an iBeacon

ble.js

var tessel = require('tessel'),
bleLib = require('ble-ble113a');


function iBeaconStart(tesselPort){

	var	uuid = 'D1CF12135FA04B2E9AC32109440633DB', // Apple's example UUID
		major = 111,
		minor = 111,
		blePort = tessel.port[tesselPort];

	var iBeacon = bleLib.use(blePort, function(err) {
		if (err) return console.log("Error connecting to slave", err);

		iBeacon.setAdvertisingData(createIBeaconAdvertisementPacket(major, minor), function (e2){
			if (e2) console.log("Error setting advertisement packet", e2);
			// start adveristing to any listening masters
			iBeacon.startAdvertising(function(e3) {
				if (e3) return console.log("Err starting to advertise", e3);
				tessel.led[1].output(1);
				console.log('waiting to be discovered...');
			});
		});
	});

	iBeacon.on('disconnect', function() {
		iBeacon.startAdvertising(function(e4) {
			console.log('started advertising after disconnect');
		})
	})

	// Major is usually meant to differentiate discrete locations (store A, store B)
	// Minor is meant to differentiate microlocations within a discrete location (corners of a store)
	function createIBeaconAdvertisementPacket(major, minor, peripheral) {
		// LE General Discovery, Single Mode Device
		var flags = new Buffer([0x02, 0x01, 0x06]);
		// Manufacturer data
		var manufacturerData = new Buffer([0x1a, 0xff]);
		// Preamble
		var preamble = new Buffer([0x4c, 0x00, 0x02, 0x15]);

		// // Apple AirLocate Service UUID
		// var airLocate = new Buffer([0xe2, 0xc5, 0x6d, 0xb5, 0xdf, 0xfb, 0x48, 0xd2, 0xb0, 0x60, 0xd0, 0xf5, 0xa7, 0x10, 0x96, 0xe0]);

		// Altitude UUID
		var altitude = new Buffer(uuid, 'hex')

		var majorBuf = new Buffer(2);
		majorBuf.writeUInt16BE(major, 0);

		var minorBuf = new Buffer(2);
		minorBuf.writeUInt16BE(minor, 0);

		// Measured signal strength
		var signalStrength = 0xc6
		if (peripheral) {
			signalStrength = peripheral.rssi;
		}

		return Buffer.concat([flags, manufacturerData, preamble, altitude, majorBuf, minorBuf, new Buffer([signalStrength])]);
	}

}

function deviceScanStart(tesselPort) {
	var blePort = tessel.port[tesselPort];
	var scanner = bleLib.use(blePort),

		ledTimeout,
		discoverPool = [],
		poolRunning = false;

	scanner.on('ready', function(err) {
		console.log('Scanning...');
		scanner.startScanning({
			allowDuplicates: true
		});
	});

	scanner.on('discover', function(peripheral) {
		if (ledTimeout) clearTimeout(ledTimeout);
	    tessel.led[0].output(1);

	    ledTimeout = setTimeout(function(){ tessel.led[0].output(0); }, 50);

		console.log("Discovered peripheral!", peripheral.toString());

		peripheral.connect(function (err) {
			if (err) console.log("ERROR connect:", err);
		});

	});

	scanner.on('connect', function(peripheral){
		console.log('managed to connect!');

		// timeout to disconnect
		setTimeout(function(){
			scanner.disconnect(peripheral, function (err) {
				if (err) console.log("ERROR disconnect:", err);
				else console.log('managed to disconnect!');
				scanner.startScanning(function(err) {
					if (err) throw err;
					console.log("Started scanning again	")
				});
			});
		}, 1000);

		scanner.discoverAllServices(peripheral, function (error, services) {
			if (error){
				console.log('Service discovery error',error);
			}
			console.log(services.toString());
		});


	});

	scanner.on('servicesDiscover', function(services){
		console.log('got services!', services.toString());
	});

}

iBeaconStart('A');
deviceScanStart('B');