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// CASE STUDY · MOBILE APP

Queezly: grade a stack of quizzes with your phone

A mobile app that turns any phone into a bubble-sheet scanner. Teachers print the answer sheets, snap a photo of each one, and Queezly grades it on the device.

Product
Barehacks' own
Type
Mobile app (Android & iOS)
Audience
Teachers
Status
Preparing for Google Play
Plans
Free, or Pro at ₱49/month
A Queezly 45-item bubble answer sheet beside the Queezly app icon

THE PROBLEM

Hours of checking, one paper at a time.

Teachers check multiple-choice quizzes by hand, paper by paper, then copy each score into a class record. Optical mark readers exist, but they are expensive machines most schools don't have.

Every teacher already carries a phone with a good camera. The question was whether it could read a bubble sheet as reliably as a machine.

WHAT WE BUILT

Print, scan, done.

  • Printable answer sheets

    Sheets in three sizes, chosen by item count, with alignment markers the scanner locks onto.

  • On-device scanning

    Computer vision reads the shaded bubbles from a photo, with no internet needed and no upload of student papers.

  • Student ID recognition

    Text recognition reads each student's LRN or student number from the sheet.

  • Classes and quizzes

    Set up classes, answer keys and quizzes, then see results and item analysis per quiz.

  • Sync and backup

    Accounts with cloud backup, so results survive a lost or changed phone.

  • Pro plan

    Free with ads, or Pro at ₱49 a month or ₱299 a year through Google Play and App Store billing.

Queezly's Print answer sheets screen, previewing two half-page sheets on one A4 page
Print sheets: the size follows the item count
Queezly's scanner finding three of four corner markers on a bubble answer sheet
Scanner: locks onto the corner markers
Queezly's results screen with the class average, pass rate and score distribution
Results: the whole class at a glance
Queezly's item analysis screen showing the mean percentage score and the hardest items
Item analysis: which questions the class missed

App designs. Real screenshots replace them when Queezly launches on Google Play.

THE ANSWER SHEETS

Three sizes, so short quizzes don't waste paper.

The app picks the sheet size from the number of items, and fits several small sheets on one printed page.

  • 15–25 items¼ A4 · 4 per page
  • 30–60 items½ A4 · 2 per page
  • 65–80 itemsLegal 216 × 330 mm · 1 per page

UNDER THE HOOD

How it's built

  • Cross-platform appFlutter, so one codebase ships to Android and iOS.
  • Scanning engineOpenCV runs on the phone to find the sheet, correct its angle and read each bubble.
  • Accuracy testingThe engine is tested against generated answer-sheet fixtures and a sweep of real photos, so changes can't quietly break grading.
  • Accounts and syncSupabase for sign-in, cloud sync and backups.
  • BillingRevenueCat manages Pro subscriptions across both app stores; the free plan shows ads.

Stack

  • Flutter
  • Dart
  • OpenCV
  • Google ML Kit
  • Supabase
  • RevenueCat
  • AdMob

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