Smart Sorting Trash Bin
Source: Stemoto Original
Teach civic sense by building an automated trash can. Cut a lid into a cardboard box and attach an EV3 motor. Program the ultrasonic sensor so that when a student brings paper near the bin, the lid automatically opens and closes after 3 seconds.
Categorisation
Props & Materials Required
- •LEGO EV3 kit (motor + ultrasonic sensor)
- •Regular cardboard box
- •Craft knife (adult supervision required)
- •Tape and decorating materials
- •Sample 'waste' items (paper, plastic wrappers)
Step-by-Step Instructions
Prepare the Bin
Take a medium cardboard box. Cut a hinged lid on the top that can swing open and closed. Decorate it with a 'Dry Waste Only' sign.
Mount the Motor
Attach the EV3 motor to the lid using LEGO beams so that when the motor turns, the lid swings open.
Install the Sensor
Mount the ultrasonic sensor on the front of the bin, facing outward. This sensor detects when someone is approaching with waste.
Program the Logic
In EV3 software, program: if ultrasonic sensor detects an object closer than 15cm → motor opens lid → wait 3 seconds → motor closes lid.
Test and Improve
Walk up to the bin with a piece of paper. Does the lid open? Does it close after 3 seconds? Adjust the sensor distance and wait time. Discuss: How could this work for wet waste vs. dry waste sorting?
Why It Works & Notes
Applying technology to solve everyday community and environmental problems. Children see that the same sensor technology used in automatic doors and parking sensors can be applied to waste management — making civic responsibility feel innovative rather than boring.
NEP Alignment: Applying technology to solve everyday community and environmental problems. Curriculum Mapping: EVS (Waste Management, Cleanliness). Target Level: Class 3.