Cellular IoT is a way of connecting physical things (like sensors) to the internet by having them piggyback on the same mobile networks as smartphones. Its infrastructural simplicity combined with the dawn of 5G position cellular IoT as a strong player in the connectivity space.
LTE-M and NB-IOTLTE-M
LTE-M, which stands for “Long Term Evolution for Machines, ” is a network standard that allows IoT devices to piggyback on existing cell networks. With essentially just a software update, LTE-M-enabled devices can communicate with the cloud, surfing the same waves as the cat photos you’re liking on Instagram. In general, LTE-M devices are best suited to “mission-critical” applications in which real-time data transfer makes the difference—for example, self-driving cars or emergency devices in smart cities.
NB-IOT
NB-IoT, which stands for “Narrowband-IoT, ” is great for areas without good LTE coverage, or when you only need to transfer small amounts of information—for example, when using a soil sensor for smart agriculture or an energy usage monitor in a smart city. NB-IoT uses only a narrow band of the total bandwidth cell towers project. If you’re deploying in an area in which GSM is the standard cellular technology—specifically, Europe and developing parts of Africa and Asia—or, on the other hand, if you foresee needing to send only small amounts of data across the internet periodically, NB-IoT might be right for you.
WisKey OverviewWisKey is RAK specifically for the Maker making a series of open source hardware brand. It consists of four categories ofproducts: WisNode (node IoT device applications), WisAP (OpenWRT AP open source hardware), WisPLC (power cat opensource hardware) and WisCam (video open source hardware). WisKey brand meaning:
WisKey=Wise+Monkey
- Wise stands for focus and profession. Combined with many years of RAK development experience, WisKey focused oncreating the most technical strength of open source hardware products.
- Monkey stands for vitality and high added value. Combined with global technology trends, WisKey will enrich the formitself, the establishment of open source ecology, continuous optimization and improvement.
WisLink development board is based on Quectel launched a new generation of Internet of thingsmodule BG96. BG96 is an embedded IoT (LTE Cat M1 and LTE Cat NB1 wireless communicationmodule without receive diversity. It supports LTE-TDD and Half-Duplex LTE-FDD wirelesscommunication, which provides data connectivity on LTE-TDD/FDD networks. It also provides GNSS1 and voice2) functionalities to meet customers’ specific application demands. (more details at https://www.rakwireless.com/en/wislink_cellular)
With Quectel BG96 and Qualcomm MDM9206 LTE modem chipset at its core, the WisLink Cellular BG96 Arduino Shield is the industry leading compact embedded cellular modem.
Simultaneously supports the tree cellular standards
- 2G/EGPRS
- 4G/LTE Cat-M1(eMTC)
- Cat-NB1(NB-IoT)
- GPS
Packed in Arduino shield form factor to leverage well-established Arduino ecosystem, it provides LPWA IoT cellular connectivity for MCU/MPU base boards on the market with Arduino headers. This gives IoT application developers desired flexibility to choose most suitable MCU/MPU for diverse IoT applications that require LPWA IoT cellular connectivity.
Built-in tri-mode cellular network support allows IoT developers to jump start deployment of IoT applications with 2G/EGPRS network that is mature and widely available to seamlessly migrate to 4G/LTE Cat-M1 (eMTC), Cat-NB1 (NB-IoT) networks that are being deployed and maturing access the globe without any hardware chance.
Added GPS support to couple with LPWA cellular connectivity allows easy adaption to popular IoT applications such as tracker, location base services (LBS), etc.
Enhanced AT commands, built-in core protocol support and availability of basic drivers for major operating systems (Windows, Linux, android) significantly facilitate software development and system integration into any IoT applications.
BG96 is a series of LTE Cat M1/Cat NB1/EGPRS module offering a maximum data rate of 375Kbps downlink and 375Kbps uplink. It features ultra-low power consumption, and provides pin-to-pin compatibility with Quectel LTE module EG91/EG95, Cat NB1 (NB-IoT) module BC95, UMTS/HSPA module UG95/UG96 and GSM/GPRS module M95. ( more :-https://www.quectel.com/product/bg96.htm)
LayoutThe WisLink Cellular BG96 Arduino Shield is built around the Quectel BG96 LPWA IoT cellular module and provides the following interfaces, headers, jumpers, buttons and connectors:
- Micro-B USB
- Micro SIM Card Slot
- Arduino Headers (UART1, UART3, RESET, PWRKEY, STATUS, AP-READY, DTR, RI, PSM_IDC, W_DISABLE, 5V, 3.3V)
- 2x4 PCM Voice Headers (i2C, I2S)
- 2x3 Digital/Analog I/O headers (ADC0, ADC1, GPIO0, GPIO1)
- 1x4 Debug UART Header (UART2)
- 1x2 USB BOOST Jumper
WisLink Cellular BG96 Arduino Shield has two push buttons to allow the user to power on/off and reset the board:
- Cellular (LTE/GSM) antenna (3GPP Bands) - UART1
- GPS antenna (1575.42+1.023 MHz) - UART3
Hologram is Global IoT SIM card M2M data with easy activation, transparent pricing, and developer-friendly tools, I got a A free developer SIM with 1MB/month included on Hologram's Global IoT Network for getting started with cellular IoT development (more info :- https://hologram.io/devplan/)
And I was using the Hologram with the WisCellular through this Tutorial.
SIM Activation
- From the Hologram Dashboard, click the Activate SIM button in the top-right corner shown below:
- If this your first SIM activation, you’ll be prompted to select an Edition: Maker, Professional, or Enterprise to move forward. This will determine which plans and features are available your connected devices.
- Next you will need to select a plan. Here you can choose between the standard Flexible Data plan for your edition, high bandwidth plans, or enterprise plans if your organization has custom pricing available from the sales team. This page will also let you set data limits to prevent unexpcted data usage on your devices.
- Once you have selected your plan you will need to enter the SIM numbers of the Hologram SIM cards you’d like to activate.
Every SIM card has an 18-22 digit unique ID printed on it. Enter your SIM’s ID in the activation form. and you can skip the payment options and activate your sim.
Note :- You can use any cellular sim to follow this guide.
Let's hack it !So now we have a great Shield in our hand powered with Cellular Connectivity, we can start with some AT Commands before getting to start actual programming
What are AT commands?
AT commands are commands which are used to control the modems where AT stands for Attention. These commands were derived from Hayes commands which were used by the Hayes smart modems. Every wireless as well as the dial up modems require an AT command to interact with a computer machine. These AT commands along with other extended commands also require Hayes command set as a subset.
And our WisCellular Shield have some set of AT Commands to talk with the hardware, and actually we are using BG96 AT Commands.
BG96 AT Commands :- https://www.quectel.com/UploadFile/Product/Quectel_BG96_LTE_Specification_V1.0.pdf
Basic Commands
- ATI - Display Product Identification Information
- A/ - Repeat Previous Command Line
- AT+COPS=? - returns a set of five parameters, each representing an operator presenting in the network
- AT+COPS? - returns the current mode and the currently selected operator
- AT+QNWINFO=? - Query Network Information
There is two way we use it, one way with Arduino, Wis as a Shield and another way is as a standalone with Quectel developer tools like QCOM, QNavigator..etc
First we can try with QCOM then we can proceeds with Arduino
QCOMQCOM is here for perform the AT Commands to test the devices functions and it's developed by Quectel.
- First download and Install the USB Driver - http://docs.rakwireless.com/en/Cellular/WisLink-Cellular/Tools/Quectel_BG96_Windows_USB_Driver_V1.0.rar
- Download the QCOM - http://docs.rakwireless.com/en/Cellular/WisLink-Cellular/Tools/QCOM_V1.6.zip
- Insert Hologram SIM on your WisCellular
- Connect WisCellular on your Computer by using micro USB cable and turn on the WisCellular by pressing the PWRKEY near the sim module, and don't forget to connect your Cellular Antenna!
- Open Device Manager (I am using Win10) and you see the connected USB devices
- Open QCOM and Select COM Port from the Quectel USB AT Port, in my case it's COM23 and Click Open Port
- In the bottom left you can see the Input String area there you can give AT Commands and In the Left part you can load AT Commands and Send Data Continuously.
- We can try some Basic commands that we listed on top.
- AT+COPS=?
(3,"IDEA","IDEA","40419",0),(2,"Vodafone IN","Vodafone","40446",0),(3,"IND airtel","airtel","40495",0),(3,"CellOne","CellOne","40472",0),,(0,1,2,3,4),(0,1,2)
and you can see the available networks I have.
- AT+COPS?
0,0,"Vodafone IN Hologram",0
and I connected to the Vodafone network with Hologram SIM
QNavigatorQNavigator tool is only used to test Quectel modules. By using this tool, you can be familiar with theworking process of main functions like Call, SMS, TCP/UDP, PPP and QuceLocator even when you do not know any AT commands.
- Download QNavigator : http://docs.rakwireless.com/en/Cellular/WisLink-Cellular/Tools/QNavigator_V1.4.zip
- Connect WisCellular on your Computer by using micro USB cable and turn on the WisCellular by pressing the PWRKEY near the sim module, and don't forget to connect your Cellular Antenna!
- Open QNavigator and Click Next to continue
- The select GSM/GPRS
- Select appropriate Port and Buadrate then click Connect to module.
- Now we can the see the information about our module and Cellular networks details.
We can even send sms to our mobile phone using this tool
- Select SMS option on the left control panel and type receiver mobile number on appropriate box and type your message, then simply press Send Message button on the bottom, and you can see the AT commands automatically going through the left window.
- I received the message that we send through the WisCellular device using Hologram SIM
I believe you understand the basics AT commands and tools for the Wis Link, now we can move to programming. we can Program the WisLinkShield in different ways, some of them listed below.
- Sending AT Commands via UART from a Master Controller
- Using WisLink Official Arduino Library
- Programming BG96-QuecOpen SDK
Arduino is an open-source electronics platform based on easy-to-use hardware and software. WisLink is Compatible with various Arduino Development boards
- Arduino UNO R3
- Arduino UNO WiFi
- Arduino Leonardo
- Arduino Leonardo Ethernet
- Arduino Ethernet
- Arduino 101
- Arduino M0
- Arduino M0 Pro
- Arduino YUN
- Arduino TIAN
- Arduino Zero
- Arduino Primo
here we are using Arduino Uno development board with the WisLink.for that you need to stack with the WisLink on top your arduino uno.
We can upload a simple sketch to test AT commands with arduino
void setup()
{
Serial.begin(115200);
while(!Serial)
{
Serial.println("Connecting......");
}
}
void loop()
{
if(Serial.available())
{
Serial.write(Serial.read());
}
}
this code will help us to send AT commands using and Arduino serial and Receive feedback and information from the device, upload this code and open arduino serial monitor on 115200 buad rate
After uploading the code open your Serial Monitor and you can send the AT commands through the textbox on the top, and please check buad rate is same as your programe, here mine is 115200 bps
WisLink Arduino LibraryRAKWireless also developed library to make our development easy with the WisLink and arduino. it's available in GitHub : https://github.com/RAKWireless/WisLTE_Arduino
so go and download it in your arduino IDE.
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