Data Handling (Smart Pie Chart & Angle Percentage Wheel)
Source: Stemoto Original
Construct a interactive Pie Chart wheel with 4 colored angle wedges. A rotary encoder measures sector angles (90° = 25%, 180° = 50%), displaying exact percentage fractions on an OLED screen.
Categorisation
Props & Materials Required
- •Rotary pie chart wheel with 4 colored adjustable wedges
- •KY-040 rotary encoder angle sensor
- •ESP32 controller board
- •0.96-inch OLED display screen
- •4x NeoPixel arc LED strips
- •DFPlayer Mini MP3 module + 3W speaker
Step-by-Step Instructions
Adjust Pie Wedge Angle
Rotate the green pie wedge to cover 1/4 of the circle.
Rotary Encoder Reads Angle
Encoder measures 90° angle.
OLED Displays Data Percentage
OLED displays 'Green Sector = 90° (25% = 1/4 of total)'.
Survey Data Mapping Quiz
Speaker: 'If 40 students voted, how many chose Green?' Child calculates 25% of 40 = 10 students → Inputs 10 on pad!
Why It Works & Notes
Pie charts represent parts of a whole as circular angles. Adjusting pie sector wedges manually while watching the OLED screen convert angles (180° → 50% → 1/2) bridges geometry with data handling.
Maths Mela Class 4 Chapter 14 | STEM Tech: Angular Encoder Telemetry & Pie Chart Percentage Conversion Algorithm — business intelligence data visualization engines.