Smart Contract — Employee Tracking

Overview

The employee tracking smart contract is aimed to be used when one party, for example, an employer agrees to pay another party, for example, an employee, for being present in a certain geographic area for a certain duration. The employee's phone sends its GPS location to a smart contract at a certain interval. Based on the pre-agreed contract codified in an Ethereum smart contract, a cryptocurrency payment is executed when all the agreed conditions are met.

Info: If at any point, the GPS sensor indicates that an employee is outside the range of the agreed GPS area, the contract state will be updated to indicate that it is out of compliance.

Technologies and Tools

Core Technologies

Technology	Purpose	Description
Solidity	Smart Contract	Programming language for Ethereum smart contracts
Remix IDE	Development	IDE for smart contract development and deployment
Hardhat	Framework	Ethereum development environment
Truffle	Framework	Development environment and testing framework
Infura	Infrastructure	Tools for blockchain application deployment
React	Frontend	UI library for web application
Flutter	Mobile	Cross-platform mobile development SDK

Implementation

Contract

The solidity smart contract has several parameters, a constructor, and methods related to location and employee.

1// Structs and contract variables
2struct Employee {
3    address employeeAddress;
4    string name;
5    bool isActive;
6}
7
8struct Location {
9    int256 latitude;
10    int256 longitude;
11    uint256 timestamp;
12}
13
14address public owner;
15mapping(address => Employee) public employees;
16Location public officeLocation;
17uint256 public radius;
18
19// Contract constructor
20constructor() {
21    owner = msg.sender;
22    radius = 100; // Default radius in meters
23}
24
25// Location methods
26function setLocation(int256 _lat, int256 _long) public onlyOwner {
27    officeLocation.latitude = _lat;
28    officeLocation.longitude = _long;
29    officeLocation.timestamp = block.timestamp;
30}
31
32function setRadius(uint256 _radius) public onlyOwner {
33    radius = _radius;
34}

Web App (Admin)

Here the admins are able to:

• Add new employees
• Get employee information
• Set office location and radius
• Set payable amount

Mobile App (Employee)

The mobile application is used to report employee location:

• Reads user's location
• Reports location to smart contract
• Location checked for range compliance
• Processes payment if conditions met

Lesson Learned

By taking on this challenge I was able to learn new concepts:

1. Understanding of Ethereum blockchain and smart contracts
2. Experience with Ethereum development environments (hardhat, truffle)
3. Building React web app and Flutter mobile app integration with smart contracts

Info: The project provided hands-on experience with blockchain development and cross-platform application integration.

Future Plan

Future works that could help grow this project:

1. Smart Contract Improvements

• Enhanced implementation
• Additional methods
• Better security features

2. Application Enhancements

• Extended employee management features
• Improved user experience
• Additional mobile app features

3. Deployment

• Testnet deployment
• Production environment setup
• Performance optimization

Reference

• How does Ethereum work, anyway?
• Ethereum Networks Documentation
• Solidity by Example
• Flutter DApps Implementation