I would like to know what device and model to use for an wireless application where I will have 1 stm32 as a master micro controller waiting to receive data and transmit data(two-way communication) from 5 slave stm32 microcontrollers.

[Rmajj.1]

The Master stm32 controller need to send talk with the particular slave in order to turn a LED . By using switch,i will turn off the led in the slave controller .The slave has to sent state of led to master controller .

There will be cases when maybe 6 of the salves will receive data one after another. So I don't know if there will be data lost.

 can you please suggest controller and sensors?

[Eleon BORLINI]

Hi @Rmajj.1​ ,

not sure this is a sensor-related topic, but let's see if I can suggest you an existing reference design for your application.

Supposing for example a wireless application based on the low energy bluetooth (BLE), there is the STSW-BNRG-Mesh, a software solution for connecting multiple BLE (Bluetooth low energy) devices in Mesh networks for IoT solutions. It enables true two-way communication between Bluetooth-enabled devices in integrated and range-extending Mesh networks. The default application is a LED light demo.

This software can run on different platforms, as described in the databrief: from standard X-Nucleo_BLE board such as the X-NUCLEO-BNRG2A1 (STM32 + BLE module) up to more custom platforms, such as the STEVAL-BCN002V1B, with embedded BlueNRG-2 SoC Bluetooth Low Energy application processor.

-Eleon

[Rmajj.1]

thank you @Eleon BORLINI​ 

STSW-BNRG-Mesh slave Bluetooth can send the data to master? If there,how can master identified that the data is from particular slave ?

Is there any example on these ble.

[Eleon BORLINI]

Hi @Rmajj.1​ ,

if you use the STBLEMesh app, you will be allowed to provision the devices using the secure key distribution method (based on ECDH) and assign the unique addresses to the nodes. Once provisioned, the master (in this case, the smartphone where you have installed the app) can configure, control and un-provision the nodes. It can create and delete groups, assign publication address and control the nodes.

About the example, STBLEMesh App can be used with firmware examples available in STSW-BNRG-Mesh, X-CUBE-BLEMESH1 and FP-SNS-BLEMESH1.

Please let me know if these indications can be useful for you.

-Eleon

[Rmajj.1]

thank you @Eleon BORLINI​ 

it will helpful for my project and i will read the above documents.

[DEdwi.1]

If you are using BLE mesh as the solution as compared to a Bluetooth central and peripheral, you will need to have a provisioner node/phone app to manage the encryption keys and the addresses of the mesh. A Bluetooth Central and Peripheral solution where the keys are managed on the device itself may be a better solution.

In a Bluetooth Central - Peripheral Solution, the Central is connected to all the 5 LEDs, and when the switch is used to turn off the LED a message is sent from the Peripheral to the Central. The message can include the Bluetooth address of the LED, which can be the 49/48 bit address of the LED.

We would use a custom GATT Service to maintain the state of the LED and send that state to the master/Central.

Using a Central and Peripheral also reduces power issues as they can be low powered, in Bluetooth mesh the mesh relay nodes are usually mains powered.

I generally feel that the complexity of the mesh is far higher to a BLE connection oriented system (more code. more components etc).