# Project Description

## Introduction

This Social Distancing Tag (SDT) is a reference application leveraging
the SmartBond Wireless Ranging (WiRa) SDK.
The application targets mainly, but not exclusively, wearable devices allowing its users
to be warned in the case they do not comply with social distancing recommendations.
In the COVID-19 pandemic context, the SDT users should not gather with a physical
distance lower than 1.5m. The users in a professional environment should be warned they are
not complying with the recommended physical distanciation.

Due to it high level of integration and the support of advanced ranging features, the DA1469x product
family is a great fit for this application.

The SDT application is built on top of the SmartBond Wireless Ranging (WiRa) SDK, for more information
please visit the [SmartBond™ Wireless Ranging SDK](https://www.dialog-semiconductor.com/products/connectivity/bluetooth-low-energy/products/smartbond-wireless-ranging-SDK) page.

## Main features

* High accuracy distance estimation
* Operates 8 hours per day, 5 days a week on a 280mAh battery
* Software Upgradeable
* Built-in CC/CV battery charger (USB Charger Detection)
* Advanced visual alert (RGB LED, ERM, Buzzer, Audio...)
* RTC for accurate log timestamp with Bluetooth profile for RTC setup
* Each device uniquely identifiable
* Interaction logging (non-volatile memory)

## Hardware description

### Block Diagram

![block_diagram](assets/block_diagram.png)

### Part Selection

Part are indicated for reference as tested during the application development. They
can be replaced by parts with similar specifications. Please refer to the 
[DA1469x datasheet](https://www.dialog-semiconductor.com/sites/default/files/da1469x_datasheet_3v1.pdf) and [AN-B-066 Hardware Design Guidelines](https://www.dialog-semiconductor.com/sites/default/files/an-b-066_da1469x_application_hardware_design_guidelines_rev1.4.pdf) for information about integration requirements. 

* Flash: [MX25U3235F](https://www.macronix.com/Lists/Datasheet/Attachments/7438/MX25U3235F,%201.8V,%2032Mb,%20v1.6.pdf)
* Battery: >280 mAh LiPo battery
* Crystals:
  * 32MHz crystal: [XRCGB32M000F1H00R0](https://www.murata.com/en-sg/api/pdfdownloadapi?cate=cgsubCrystalUnits&partno=XRCGB32M000F1H00R0)
  * 32KHz crystal: [ABS07-32.768KHZ-7-T](https://abracon.com/Resonators/ABS07.pdf)
* Visual alert: LED
* Inverted L shaped antenna: [Dialog development kit Gerber](https://www.dialog-semiconductor.com/sites/default/files/g-l-e-b-da14695-db-vfbga86_vd.zip)
