Question: Can a nrf51822 acting as a server/slave message a client/master (iPad), that it has bonded with previously, to let it know that new data is available without having a link open?
Why? I want to have a lot of custom devices running nrf51822s communicate with the iPad but the iPad can only sustain 8-10 Bluetooth connections at each point in time. The link has to be able to transmit data fast in both directions.
Background I have a working system which consists of a number of custom devices, equipped with various sensors, each running equipped with a nrf51822 which communicates with an iPad via Bluetooth. The communication is 2way and has to happen as fast as possible or at least fast enough to be perceived as "instant" by the human eye. This is especially important when the devices send updates regarding measurements to the iPad.
In the current setup, the link between the devices and the iPad is kept open and works very well with up to 10 devices. However, due to limitations of the iPad, using a larger number of devices at the same time instant is impossible.
Recently a need to add more devices to the system arose. To be able to do that an architecture change is needed. That is, the connection can not be kept open to all the devices all the time. The main problem is the one stated above, how can the client know when a server has a new update when the link is not open?
My first idea was to use advertising packets to do so but I'm not sure it can be done fast enough. Ideally, I would want each peripheral device to be able to hint to the iPad that it has new data. The iPad would then initiate the connection, receive the data in question and close the connection again.
Anyone out there who can point me in the right direction? I'm having problems figuring out what's the best way to go about this or if it's possible at all.
