Develop Reference

How to build indoor navigation for a railway station?

I want to build an android app for indoor navigation of a railway station. Is it possible through beacons? I was wondering if I can use beacons as a starting point reference and then use the accelerometer and other sensors to calculate speed and direction.
If I want to implement it through beacons, which beacons should I go for? Beacons with great development support would be preferred.

Esimote is the most used beacon.
You can write a program for it using Android beacon library as well.
Here in Stackoverflow questions need to be more direct and more code related.

Will all Eddystone™ capable beacons support URL transmission?

I'm new to this beacon technology. I want to use this technology. I did some R&D on this and came to know that Estimote ,RadiusNetworks and some other are we can use. But now I want to take a Beacon which will support most of the concepts like
Should be capable of both Eddystone™ & iBeacon™
Transmit some sensor's (not necessory) data
Transmit URL
Now my question is
if the beacon is capable of Eddystone™ then will it transmits URL?
If you have any idea on Beacons for testing all the features & usecases which beacon you'll prefer?

Eddystone standards consist of multiple frames including UID, URL, TLM and EID, there is no requirement that all beacon models implement all these standards implement all of them. You should check with the manufacturer to verify before purchasing. The same goes for iBeacon format support.
Generally, any beacon that supports Eddystone at all supports the UID, URL and TLM frames. The EID frame was added later so older Eddystone beacons certainly do not support it.
For Radius Networks beacons, Eddystone-URL is supported by all Eddystone compatible models, as is iBeacon and newer models sold since May 2016 support Eddystone-EID as well.
Full disclosure: I work for Radius Networks.

What is difference between beacon and normal ble detection in android?

when beacon is more useful in ble application in android?
What are the benefits to use beacon ,is i know we can customize background scan rate. but using normal ble also we can change background scan rate by using SCAN_MODE_LOW_POWER and other flags. both will decrease the scan period.
can anyone explain these

Beacons as a specialized version of a Bluetooth LE device. They are designed as transmit-only devices that simply send out a unique identifier at regular intervals, typically at 1-10 Hz. Beacons send out these identifiers using Bluetooth LE Advertisements, a feature which is a relatively small subset of the Bluetooth 4.0 specification.
Beacon-specific Android libraries like the Android Beacon Library are designed to focus on the use case of detecting Bluetooth LE beacons as opposed to doing more general purpose Bluetooth LE operations. A beacon library adds logic on top of built-in Android BLE Scanning including:
Parsing of beacon identifiers from raw BLE advertisements, based on different beacon formats (Eddystone, AltBeacon, iBeacon, etc.)
Event-driven APIs to tell you when a specific beacon identifier pattern is first seen and then stops being seen.
Regular callbacks (e.g. once per second) telling you a list of which beacons are visible.
Distance estimates to beacons.
Automatic switching of scan intervals as the app switches from the foreground to the background.
Automatic wakeup of the app when beacons are detected.
While it is possible to do all of the above with the lower-level Bluetooth LE APIs in Android, you have to write a lot of code to build these features yourself. Using a beacon library allows you to focus on your App's business logic and leave the complexities of dealing with the beacon parsing and detection functions to somebody else.
Full disclosure: I am the lead developer on the Android Beacon Library open source project.

RadiusNetworks iBeacon library for android: calibration

I am using the RadiusNetworks library for measuring the distance to iBeacons. The official app from RadiusNetworks (iBeacon Locate) provides a calibration feature to improve accuracy.
How do I perform a calibration when using the library as part of my application?
Thanks & Best
ben

The calibration function in the BeaconScope app will give you a number to be configured into a hardware beacon to make distance estimates as accurate as possible. Once set, the beacon transmitter will emit this value to receiving devices (both Android or iOS). Because it is transmitted over the air, there is no need to manually configure the Android iBeacon Library with the value. The library will read it out of the beacon transmission.
For this to work, you need to configure the calibration power value into your beacon. How you do this depends on the type of beacon you are using. Most beacon vendors allow this, but each product has a different procedure. For my company's RadBeacon products, for example, we have iOS and Mac apps to set this value over the air.

It is hard to estimate the accurate distance using RSSI of the iBeacon.
You have to use log distance path loss model(shortly, LDPL) to change RSSI to distance.
In LDPL, you need below two parameters, simply.
Initial RSSI
Path loss exponent
And I recommend you BeaconBox for Android.
You can get these two parameters using this app.
Also, you can get Java source code for changing RSSI to distance.
I hope that you achieve the goal!

Is it possible to change an iBeacon beaconing frequency with Android?

I am currently developping an Android application that can monitor the signal strength of an iBeacon with the library Android iBeacon Library (http://developer.radiusnetworks.com/ibeacon/android/).
But because we want to use iBeacons with very slow frequency to save battery, I need to be able to increase the frequency for a few minutes to have frequent detections during the signal strength monitoring. The problem is that the library I am using does not seem to provide this functionnality. I searched the web for other libraries that would offer this feature, but I can't find any.
Do you know a library that would let one change the beaconing frequency of an iBeacon? If not, how should I proceed to code it?

My revised understanding of your question is this: You want an Android library that communicates with an iBeacon to dynamically change its advertising rate.
Unfortunately, I think the Android side is the easy part. The hard part is that no iBeacon manufacturers I know of have an open API that allows you to dynamically change the advertising rate. (Although some do let you use an app to configure this rate over a secondary Bluetooth connection. Radius Networks' small USB-powered iBeacons work this way.) Because each vendor's service works differently, you'd have to reverse-engineer how each of their configuration BLE services works.
If you really want to do this, here is how I would approach it:
Build your own custom iBeacon that has a secondary Bluetooth LE service that allows you to connect to the beacon and change its advertising rate. A great way to prototype this would be with an iOS device acting as an iBeacon or with one of my company's iBeacon Development Kits. For an iOS-based beacon, you can write the secondary service in Objective C. For the IDK beacon, you can write the software in any language supported by Linux.
Write custom Android code that connects to the bluetooth service and sets the advertising rate as needed. You could use this alongside the Android iBeacon Library. And as an open-source project, you could always offer to merge your code into it once you have it working. (I'm the guy to talk to!)
Once you have this working, talk to an iBeacon vendor to make custom firmware for a battery-powered beacon that does the exact same thing. Hardware suppliers will tell you how to make custom firmware. This typically requires a proprietary workbench tool and is done in C or in a proprietary scripting language.

Yes! The Android iBeacon Library from Radius Networks Supports this. Below is sample code that changes both the foreground and background scan period to be every 5 minutes. What this means is that the library will spend five minutes doing scanning, and let you know what iBeacons it sees during that time. (The foreground default is 1.1 seconds.)
You can change this frequency as you wish based on some algorithm in your app.
iBeaconManager = IBeaconManager.getInstanceForApplication(this.getApplicationContext());
...
#Override
public void onIBeaconServiceConnect() {
try {
long five_minutes_in_millis = 5*60*1000l;
iBeaconManager.setForegroundScanPeriod(five_minutes_in_millis);
iBeaconManager.setBackgroundScanPeriod(five_minutes_in_millis);
} catch (RemoteException e) {
e.printStackTrace();
}
}
Full disclosure: I am an employee of Radius Networks and the primary author of this library.