what is the maximum range to connect 2 NRF51822 devices with Gazell

RE: what is the maximum range to connect 2 NRF51822 devices with Gazell

Sigurd — Wed, 28 Sep 2016 11:23:08 GMT

The close proximity pairing feature in Gazell uses the RSSI measurement to detect if a device is in pairing range.

On the host side, the RSSI is compared against a threshold to decide if the device is in range, and is defined as

#define GZP_HOST_RX_POWER_THRESHOLD -64 ///< RSSI threshold for when signal strength in RX packet power is high enough.

If you want to extend the pairing range, you can adjust this threshold to fit your requirements.

RE: what is the maximum range to connect 2 NRF51822 devices with Gazell

Tim — Wed, 28 Sep 2016 11:15:31 GMT

Hello, Thank you for the quick response :).

RE: what is the maximum range to connect 2 NRF51822 devices with Gazell

Jørgen Kvalvaag — Wed, 28 Sep 2016 11:01:56 GMT

This is a security feature implemented in the gazell pairing library, to prevent bonding to any "wrong"/malicious device. This library is delivered as source code in the SDK, so it is possible to change this behavior.

Basically the gazell library transmits the pairing request using low (-16dBm) tx power, so only devices in close proximity will receive it.

To be able to do pairing using normal tx power one only needs to change one line in the file nrf_gzp_config.h(line 53):

/**
Reduced TX power for use during close proximity pairing.
*/
#define GZP_POWER NRF_GZLL_TX_POWER_N16_DBM

change to:

#define GZP_POWER NRF_GZLL_TX_POWER_0_DBM