Sometimes, Central fails initial connection with peripherals

[nordicdev]

Hi,

I have 3 nrf51822 devices. Two of them act as peripheral and one acts as central. Each peripheral is used in a wheel and they are the 2 wheels of a cart. Central is in the remote that controls the cart with 2 wheels.

Min connection interval for peripherals: 7.5msec

Max connection interval for peripherals: 30msec

Advertisement interval of peripherals: 200msec.

What I have observed is that: one in times, when there are only 2 extra bluetooth devices around, the central does not connect always with both the peripherals. It connects with one peripheral, but when it connects to another peripheral, it gets a disconnect event, and retries, but in vain.

Is this behaviour expected? If so please advice as how to handle this such that connection and bonding from central happens to both the peripherals every single time?

[run_ar]

Are the other "extra bluetooth devices" central device? If these are active scanners they might block the connection request occationaly.This behavior would be worse if the extra device is a lot closer to your peripheral than the wanted central.

[run_ar]

Also what is your scan window, and scan interval? Make sure the interval does not match the advertisment interval. i.e. since you are advertising at 200ms you should use a scan interval that makes sure the scan window overlaps with the advertisements.