BLE & LoRa based Indoor Location Tracker without GPS

Hey, what's up, Guys! Akarsh here from CETech.

GPS-based location tracking is one of the very important services nowadays. We use this to find a path to our destination and also track the position of our goods using this. But have you ever heard of location tracking without using GPS? Today we are going to discuss the idea of making a location tracker using BLE and LoRa Technology. We are not going to make one today but we will discuss how it would work. But before that, we are going to discuss what's inside the modules that can make this application possible. We have the LBT01 LoRa based GPS tracker and BLE Beacons from LoRa. We will tear them out and after that, we will check what's inside them that makes all the applications possible.

So let's get to the fun part now.

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What is BLE?

Before we get to the tearing and studying of the BLE Beacons that we have. We need to understand what BLE is and how it works. BLE stands for Bluetooth Low Energy. It is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group (Bluetooth SIG) aimed at novel applications in the healthcare, fitness, beacons, security, and home entertainment industries, etc. Compared to Classic Bluetooth, Bluetooth Low Energy is intended to provide considerably reduced power consumption and cost while maintaining a similar communication range. Bluetooth Low Energy technology operates in the same spectrum range (the 2.400–2.4835 GHz ISM band) as classic Bluetooth technology but uses a different set of channels. Instead of the classic Bluetooth seventy-nine 1-MHz channels, Bluetooth Low Energy has forty 2-MHz channels. Within a channel, data is transmitted using Gaussian frequency shift modulation, similar to classic Bluetooth's Basic Rate scheme. The bit rate is 1 Mbit/s (with an option of 2 Mbit/s in Bluetooth 5), and the maximum transmit power is 10 mW (100 mW in Bluetooth 5). Bluetooth Low Energy uses frequency hopping to counteract narrowband interference problems. Classic Bluetooth also uses frequency hopping but the details are different; as a result, while both FCC and ETSI classify Bluetooth technology as an FHSS scheme, Bluetooth Low Energy is classified as a system using digital modulation techniques or a direct-sequence spread spectrum.

LoRa technology is also used here but we are not going to discuss that today. If you want to know more about LoRa you can get that from here.

Inside LBT1 LoRaWAN BLE Indoor Tracker

LBT1 is a Long Range / low power consumption LoRaWAN Bluetooth tracker. It is similar to the LoRaWAN based GPS Tracker which we used a few projects back. You can check that out from here or check out the video below.

LBT1 scans and finds the nearest i-Beacon info and sends it to the IoT server via LoRaWAN wireless network. IoT Server should have a pre-configured position mapping for beacons in order to trace the location of the LBT1 tracker. LBT1 targets indoor positioning for people and things. LBT1 has a motion detection feature, it will also, detect walk steps and uplink the value. LBT1 is powered by a 1000mA rechargeable Li-on battery and charging circuit, which target real-time tracking with short tracking uplink interval.

Technical Specifications of the LBT1 are:-

• MCU: STM32L072CZT6
• Flash:192KB
• RAM:20KB
• EEPROM: 6KB
• Clock Speed: 32Mhz

This was a brief about the LBT1 LoRaWAN BLE Tracker from Dragino. Now we are going to discuss what's inside this tracker. When we open the white casing of the device we get to see the PCB of the Tracker. There's nothing much on the lid except the translucent silicon covering over the LED and the big red button. Coming to the PCB we have a push button that is used as an SOS button or can be programmed for any other purpose as well. We have a power switch that turns the device ON or OFF. Apart from that, the major components that are for providing connectivity and controlling the device are as listed below:-

• BLE Chip: It has the NRF52832 BLE chip from Nordic. It is the chip that provides Bluetooth connectivity and covers all the communication that goes on with the BLE Beacons. To study about this in detail you can head over to its datasheet from here.

• STM32 based Microcontroller: This tracker is loaded with an STM32L072CZT6 microcontroller. It is the brain and the heart of this Tracker. It controls all the communications that go on inside the node and all the other necessary controlling part for the functioning of the node. You can read about this in detail from here.

• RFM95 LoRa Chip: This is the chip that is responsible for all the LoRa based communications that go on with this node. It connects the node to the gateway and sends the data to that gateway. It has a flexible antenna with it as well that is bent under the board. You can read about this in detail from here and get some additional information about this module from here.

We also have a battery management chip and a programmer chip and a USB port through which we can charge as well as program the device. We have 4 pins as well that can be used to program the STM32 based microcontroller to function according to our need. The pins are RST, CLK, DIO, and GND. Under the board, we have a 1000 mAh battery that provides power to the device and keeps it ON. It is a rechargeable battery. So all these components combine to make the LBT1 LoRaWAN BLE Indoor Tracker which can be used in various tracking applications.

You can get your LBT1 tracker from here.

Inside the BLE Beacons

Till now we have discussed what BLE is and after that, we opened and checked what was inside the LBT1 LoRaWAN BLE Indoor Tracker. Now we will get to know what BLE Beacons are and what's inside them. For this purpose, we have BLE Beacons from Dragino. You can get them from here. BLE beacons, as the name suggests are beacons that communicate via Bluetooth Low Energy. Beacon devices are small radio transmitters, strategically mounted throughout locations, to broadcast low energy Bluetooth signals in a given range. This range depends on hardware capability. On average, a beacon device can transmit BLE signals to 80 meters. This BLE signal from the beacon is capable of triggering a specific action relevant to the location. Beacons send out an ID number via BLE channels, approximately 10 times every second. A Bluetooth-enabled device in proximity of the beacon picks up this ID number and performs the task for which the beacon is programmed.

Now we are going to see what's inside these beacons. As we open up the beacon's outer covering we see a pretty small and simple PCB. It has a push-button on it that is required for switching the beacon On or OFF. It also has a CR2032 battery which is a sleek 3V coin cell battery that powers up the device. This battery can last up to 4-5 years as the BLE signals use very little power. It has a battery holder, a ceramic antenna, and a Crystal Oscillator as well but the heart of the beacon is the NRF52832 BLE chip from Nordic. This is the chip that is responsible for all the communications that happen over BLE with this beacon. You can read about this chip in detail from here. All the beacons have their own ID number that differentiates them from other beacons.

BLE based Indoor Location Tracker

As we have got to know about the components that will be required for this Tracker to be made, Now we can move on to the idea about how this Tracker will work. The tracker will be useful in tracking at places where the object to be tracked has a specified moving path. That is the object will traverse the same path again and again. For example, if we need to track the movement of some self-driving autonomous forklifts within a Warehouse. What we will be going to do is that we will place an LBT1 LoRaWAN BLE Tracker on each of the devices that are to be tracked and according to the number of devices that are to be tracked we will select a suitable LoRaWAN Gateway and configure these in order to send data from the Trackers to the Gateway. After that, we will decide on some locations where the BLE Beacons can be placed. The locations where there are fewer obstructions around needs to be selected as it will help in increasing the range that the beacon can cover. Also, the beacons are to placed in such a manner that the complete path is covered by the beacons. Now the device with Tracker will be left to move and whenever the Tracker comes in the range of any beacon. It will send the ID number of the beacon to the Gateway and from there on to the server from where the data can be easily checked. In this way, the device will be able to keep a check on the path that the device follows and if at some point in time there is any change in the pattern in which the IDs of the beacons are received. We will get to know that the wrong path is followed by the device.

So this was the idea of the BLE based Indoor Tracker with the help of BLE beacons and LBT1 LoRaWAN Indoor BLE Tracker from Dragino. We also got an insight into what's inside these devices that make them capable of doing all this stuff. Hope you liked the tutorial, Looking forward to seeing you next time.