Mesh networking for security system

Question

Hey Guys,
Thanks for this wonderful first of all.
Great work! 
 Well I am posting my first query related to Nordic mesh, please help 
 we need the BLE for our Wireless Security Alarm System Project on MESH Technology which work something like that: 
 
 
 We attached one BLE as master with our main control panel through UART or any other protocol & want to control the BLE with our principal controller. 
 
 
 We want to attached nearly 100 ( or more) different BLE as Slave with different address with our Master BLE. 
 
 
 2.a. when Master BLE is in programming mode, & we press the programming switch of any slave BLE, then slave send the own address to master BLE & it automatic store the slave address. similarly the same process for all slave BLE`s. 
 2.b. After saving all the addresses of all slaves BLE`s, master BLE comes out from the programming mode when it get the command from main controller. 
 2.c. . Now the master BLE will be in the running mode and check the address and data from slave BLE side on regular bases. 
 2.d. All slave BLE send the data to main Master BLE directly or through nearest available slave BLE on regular interval to confirm that they are in MESH, & master check the address of slave if address match with save data address then master work on it otherwise it would skip that data. 
 
 
 In first case, All Slave BLE connect directly to Master BLE if they are in direct range. 
 
 
 In second case if any slave BLE will not in direct range of Master BLE, then the Slave No. 1 send the single to nearest available Slave BLE & the 2nd slave again transmit the single or data to main Master BLE with the complete data with slave BLE code to Master BLE to recognise it from which Slave its come. 
 
 
 Vis versa when Master BLE want to send the data to any slave BLE then the Slave BLE receive it if the data for it or it will forward to other available Slave BLE. 
 
 
 The above is main operation what we want to do with BLE. 
 So can we implement the above project using Nordic mesh network?if yes please guide us on how to proceed with the same? please share related documents. 
 kind regards
PK

Bjørn Kvaale · Accepted Answer

It should definitely be possible to implement this using Nordic devices. I would start off by taking a look at the Mesh SDK and downloading the latest version. 
 What you are referring to is called provisioning (i.e. adding a device to the mesh network). The provisioner (i.e. master in your case) is the network owner & the provisionee (i.e. the slave device) is the device that should be added to the mesh network. The provisionee device receives an address, a network key & a device key from the provisioner. The device key is a special key used for private communication between the provisioner & the provisionee. Essentially, the provisioner provides the provisionee with all of the information required for the provisionee to join the mesh network. 
 In your usecase, you want to make the slave send their address to the master, but the Bluetooth Mesh specifications say that this should be the other way round. By this, I mean that the master will provide the slave with the address & the master will store this address for future use. 
 Also, you refer to regular communication between the master and the slave when the master is in running mode. I believe you are referring to a heartbeat message (see this link & search for "heartbeat"). The main purpose of the heartbeat message is to allow one node to tell the other nodes that the node sending the heartbeat message is still active and "healthy" (i.e. has a pulse). You can also configure how often this hearbeat message should be sent and for how much time they should be sent. You can also calculate the distance between the master & slave by counting the number of hops required to deliver the heartbeat message. 
 If a slave cannot communicate directly to the master device (or vice versa), you can use a Nordic proprietary feature called remote provisioning. This allows a provisioner (i.e the master) to add a provisionee (i.e the slave device) even if the distance is greater than the radio range between the two devices. This is possible to creating a "tunnel" through the mesh network with use of a PB-ADV proxy device. In the Mesh SDK, you can find an example for remote provisioning of the client & the server . 
 To summarize, this should definitely be possible, but you should familiarize yourself more with Bluetooth Mesh in general by either reading the Bluetooth specifications and/or reading Martin Woolley's amazing blog posts on Bluetooth Mesh (read Part I & 2). I can highly recommend reading Martin Woolley's blog posts, as Mesh is explained in a concise and simple manner. Hope that helps! Let me know if you have a related query. :) 
 Kind Regards, 
 Bjorn