Sensor network using Gazell peripherals and BLE for PC connection

[ImQ009]

I would like to create a sensor network consisting of up to 17 nodes, I've been collecting a lot of information about means of communication between them and a computer and I came to conclusion using Gazell for collecting data from all nodes into a a central node, which then would connect to a PC via BLE for interaction would be the best solution. But then the central node would have to be both a Gazell master for communicating with the rest of the sensors and a BLE slave for PC interaction. The information from the sensors has to be sent to the PC in real-time.

Here's a little draft I made (forgive me for lacking any sort of graphic design abilities)

How would I do that? I'm still very new to all this and I'm not even sure if it's a viable solution. Maybe I should just ditch the whole idea and go for something entirely else? Any sort of advice would be highly appreciated. Thank you

[Asbjørn]

I think your initial thought is a good way to go. You can use Gazell to gather the information from the sensors and then have one of them to also do BLE. You can either have the collector do Gazell by using the timeslot API.

Have a look at the ESB/Gazell examples in the nRF51-SDK and there's an example on Github using the timeslot API.

You can for example have different sensors with same functionality using specific pipes on the Gazell host.

[ImQ009]

Thank you, I've read about the timeslot API and it's all clear for me now. Except I ran into another question: how do I connect all those sensors to a single central? In the draft I made I was assuming I could make the sensors work as both a host and a device at the same time, because of the Gazell connection limit which is only 8 devices. Or am I misunderstanding it and the device number isn't the actual limit here but the ammount of pipes? If that's the case could I have like 2 devices per pipe? Are there any examples of anything like this? Thank you again

[Asbjørn]

You can't have them as both host and device, but you can use ACKs to send back information the other direction. Regarding pipe and number of devices, you are correct, you can have multiple devices on the same pipe. Use part of the payload as sub-addressing.