Datasheet

orientation, RSSI will fall. You can read the RSSI value between two connected devices

with the AT+BLEGETRSSI command, but there are no meaningful and repeatable

conclusions that can be drawn from this value about distance other than perhaps 'farther'

or 'closer' in a very loose sense of the terms.

How far away from my phone can I have my Bluefruit LE module?

This depends on a number of factors beyond the module itself such as antenna

orientation, the antenna design on the phone, transmit power on the sending node,

competing traffic in the same 2.4GHz bandwidth, obstacles between end points, etc.

It could be as low as a couple meters up to about 10 meters line of sight, but generally

Bluetooth Low Energy is designed for very short range and will work best in the 5-6 meter

or less range for reliable communication, assuming normal Bluefruit firmware settings.

How many GATT services and characteristics can I create?

For firmware 0.7.0 and higher, the following limitations are present:

Maximum number of services: 10

Maximum number of characteristics: 30

Maximum buffer size for each characteristic: 32 bytes

Maximum number of CCCDs: 16

Is it possible to modify or disable the built in GATT services and characteristics (DIS, DFU,

etc.)?

No, unfortunately you can't. We rely on the Device Information Service (DIS) contents to

know which firmware and bootloader version you are running, and wouldn't be able to

provide firmware updates without being able to trust this information, which i why it's both

mandatory and read only.

Similarly, the DFU service is mandatory to maintain over the air updates and disabling it

would create more problems that it's presence would cause.

How can I use BlueZ and gatttool with Bluefruit modules?

BlueZ has a bit of a learning curve associated with it, but you can find some notes below

on one option to send and receive data using the BLE UART Service built into all of our

Bluefruit LE modules and boards.

These commands may change with different versions of BlueZ. Version 5.21 was used

below.