I have a wireless project. Requirements as:
many connections: flexible but can support 100+ connections
Response time: human response time, about 100ms
Device Input: just 1 button press, and the platforms will recognize which device button is pressed
I think the design is like this: (BLE Central platform(s) )<==button press UUID info.==(BLE Peripheral device)<==button press UUID==(BLE Central button device 1, 2, 3...100...)And targeting nRF51/nRF52 for my development.So, my questions are:
I see people said Mesh network can connect 100+ nodes. Is it mesh rather than star network in connecting many nodes?devzone.nordicsemi.com/.../how-many-node-can-connect-to-a-node-in-ble-mesh-network
With standard BLE using our Softdevice, the concurrent connections is limited to 20, so that won't work for you I guess.
I think you will have to consider using a mesh solution for your project. Using Mesh there isn't really a real upper limit of the number of nodes in your network. The theoretical max number is 32768 nodes.
1. Yes, if you are using Mesh, there shouldn't be a problem connecting 100+ nodes. As you can see from my comment above the theoretical max number is very high, so I don't know of anyone that has done a test using that many nodes.
2. Yes, the nRF52832 does offer double the amount of flash compared to the nRF51.However, there are some data that needs to be stored for each new node stored on the provisioner, such as the device key, the node address if the provisioner want to re-configure a node. That is why we actually don't recommend to use the nRF52 as a provisioner, but instead the database should be stored on PC or mobile phone.
3. In a sense, yes. The number of nodes will affect the response time, depending on the distance between them and the no_of_hops. The latency in the mesh network would be (2ms + advertising_interval) / 2 * no_of_hops.
4. In general I would always suggest using the nRF52-series. Note that the Mesh SDK has deprecated nRF51, so you should really consider using nRF52 for new product development.
5. From what I can see it looks like a good fit to use Mesh for your project.
More documentation and information below: Blog - Introducing nRF5 SDK for MeshInfocenter documentation - SDK for MeshBlog - Things you should know about Bluetooth MeshBlog - Provision, Configure and control Bluetooth mesh networks with nRF Mesh
Also, there is a lot of Q&Aa regarding mesh around DevZone so you might be able to find the information you need here. If you can't find what you need, you are welcome to post a new question here on DevZone.
Best regards, Joakim.