Monthly Archives: August 2020

BLE Generic Attribute Profile (GATT)

See this Microchip Developer page: The Generic Attribute Profile (GATT) establishes how data will be organized and exchanged over a Bluetooth® Low Energy (BLE) connection. Certain use-case-specific profiles (GATT-Based Profiles) are standardized by the Bluetooth Special Interest Group (SIG): – Heart Rate Profile – Proximity Profile – … GATT uses the Attribute Protocol (ATT) as… Read More »


A UUID is a Universally Unique Identifier. For BLE devices, the 128 bit UUID represents a specific profile, service or data type. It is guaranteed to be unique across all space and all time according to the Bluetooth 4.2 spec. Each UUID is a 128 bit value. Some examples are: You will see that the… Read More »

Pair HC05 BT Modules

Steps taken from comments on an Amazon listing for DSD devices: I bought two of these to allow me to communicate between 2 arduinos. I had googled a little and it seemed simple enough from the examples I had seen, but once I got the chips I discovered none of the examples I found on-line… Read More »