# Barcode Scanner

### Barcode Scanner Lesson

Driving Question: How far does the x-y pattern generator or barcode scanner, have to be placed from a two-dimensional barcode (a QR code) to properly read it?

Synopsis: Barcode scanners need to scan the entire area of a barcode to properly read it. The x-y pattern generator used in this lesson displays a pattern at a fixed angle, the amount of area that it can cover is dependent on how far away the x-y pattern generator is from the barcode. Students will determine how far away the x-y pattern generator needs to be placed in order to properly scan a QR code. Students will apply their knowledge of congruence and similarity criteria for triangles to find the ratio between the size of the x-y pattern and distance from the x-y pattern generator.

Math Standards: Students will
• Prove theorems involving similarity
• Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.
• Define trigonometric ratios and solve problems involving right triangles
• Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.
• Use trigonometric ratios and the Pythagorean Theorem to solve right triangles in applied problems.
• Apply trigonometry to general triangles.
• Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and non-right triangles (e.g., surveying problems, resultant forces).

MCC OPT 110 Topics:

How Light Behaves – reflection
Light in Technology and Industry – Lasers (barcode scanners)