Conference Check-In System

1. Overview

The Conference Check-In System enables attendees to gain entry using personalized QR codes.

• Before the event, each attendee is emailed a unique QR code
• At the venue, volunteers scan QR codes with their phone camera
• The system validates against a Google Sheet database, updates their check-in status, and logs the time
• A GitHub Pages dashboard displays real-time check-ins and prevents duplicate entries

2. Components

2.1 Google Sheet (Attendee Database)

Central source of truth.

Columns used:

Column	Field	Example
A	Name	John Doe
B	Email	john@example.com
C	Status	Sent / Error
D	Check-in Status	✅ Checked in / blank
E	Check-in Time	10:15:22 AM
F	Pass Type	VIP / Regular
G	Embed (QR content)	john-doe-vip-unique123

2.2 Google Apps Script (Backend)

QR Generator Script

• Creates QR codes using the Embed field
• Sends via Gmail with plain text + HTML body
• Marks email as "Sent" once delivered

Check-In Script

• Exposes a web endpoint
• Validates scanned QR against Embed column
• Updates Check-in Status + Time
• Prevents duplicates
• Returns JSON response

Example JSON Response:

{
  "success": true,
  "message": "✅ John Doe (VIP) checked in",
  "time": "2025-09-06T10:15:22.000Z"
}

2.3 GitHub Pages (Frontend)

• Hosted static site
• Uses html5-qrcode library
• On scan:
  • Sends POST request to Apps Script endpoint
  • Updates UI with check-in confirmation
  • Adds entry to live log table

fetch("https://script.google.com/macros/s/<DEPLOYMENT_ID>/exec", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ name })
});

3. QR Code Generation

Function: generateQRImagesToDrive

• Iterates over attendee list
• Uses QuickChart.io QR API
• Sends QR to attendee's email
• Updates Column C (Status) with "Sent"

Key Variables:

const nameCol = 0;   // A: Name
const emailCol = 1;  // B: Email
const statusCol = 2; // C: Email sent status
const embedCol = 6;  // G: Embed (QR content)

4. Check-In Backend

Function: doPost(e)

• Validates scanned QR
• If valid → marks attendee as checked in
• If already checked in → returns "already checked in"
• If invalid → returns error

Deployment:

• Execute as: Me
• Access: Anyone
• URL format: https://script.google.com/macros/s/<DEPLOYMENT_ID>/exec

5. Frontend

File: index.html

• Loads camera scanner
• Displays confirmation or error
• Updates table log dynamically

Sample Flow:

1. Volunteer scans QR
2. Browser sends request to Apps Script
3. JSON response is displayed on screen
4. Log table updates in real-time

6. Workflow

Prepare Attendee Sheet

1. Consolidate names & emails
2. Add Embed column: =Name & " - " & Pass Type
3. Copy & paste values (not formulas)

Run QR Generator Script

1. Emails QR codes
2. Updates Status column

Deploy Check-In Backend

1. Deploy as web app
2. Copy web app URL

Configure GitHub Pages Frontend

1. Update index.html with backend URL
2. Push changes to GitHub

Event Day

1. Volunteers open GitHub Pages link
2. Scan attendee QR codes
3. Sheet + dashboard update live

7. Error Handling

Error Type	Message Example
Invalid QR	⚠ Invalid or empty QR code
Not Found	❌ Name not found
Already Checked In	John Doe already checked in
Network Issue	⚠ Network error
Email Failure	Error logged in Column C

8. Key Benefits

✅ Works on any smartphone browser
✅ Supports multiple scanners at once
✅ Live sheet prevents duplicate check-ins
✅ Easy to reuse for future events

9. Future Improvements

• Admin dashboard with live stats (total attendees, % checked in)
• Manual override for failed scans
• Pass type filter (VIP / Regular)