Overview:
trigram_app is the partner app to the trigram device, that helps people track how well they are socially distancing themselves
It connects to the trigram device over BLE UART and collects the bluetooth mac addresses that the trigram devices sends over
The greater the density of the devices seen, the greater likelihood that a BLE CENTRAL device, like a smartphone is approaching you
This app displays the amount of devices seen every second on a graph UI, and logs encounters in a Firebase database
We can approximate that one person ~ one phone
This project works best in open environments!
Getting started:
git clone this repository
Open trigram_app in Android Studio
Create your own firebase database and replace google-services.json with your own
You can follow steps here:
Firebase Real-Time Database
Operation process:
Open trigram_app and you should be greeted with:
Click scan and connect to NORDIC_UART:
The GraphView UI displays how many devices seen nearby:
Open your Firebase Real-Time Database and it should look like this, where each timestamp represents devices seen at that moment in time:
Technical notes:
some ble characteristics are not "read"-able
for example, the ble uart TX characteristic is "notify" and not "read" so to read data from ble uart, set up notifications, descriptor, and onCharacteristicChange however, the ble uart RX characteristic is "write" with no descriptor so to write data to ble uart, perform writeCharacteristic method