Lesson 2 - Seedling Stage: Auto Light Control

Lesson 2 Seedling Stage: Auto Light Control

Challenge 2-1, 2-2

Students will engage with the concept of inputs and outputs and how these can be used in this model.

I can use inputs to a sensor to control the outputs of an LED strip.

I can explain the relationship between inputs and outputs in a system.

I can modify the code to complete a challenge.

Engage

2 min.

A seedling box is essential for seed starting because it holds multiple seeds efficiently, simplifies watering, lighting and transplanting.

How can we make sure the seeds get enough light even on a

cloudy day?

Background

3 min.

How does the seedling box know the weather? The light sensor reports the intensity of ambient light from 0–4095, where 0 is full darkness and 4000–4095 is direct sunlight. The ambient light value in the average cloudy day is anywhere from 2000 to 3000.

How does the seedling get extra light? The LED strip has seven LEDs, each LED can be set to different colors, brightness, and switch states. So that it can be adjusted according to the light color and brightness required by the seeds.

Build

15 min.

Build together by the Building instruction.

After groups finish building, prompt them to discuss the question below:

Where can we install the LED strip?

Is the light sensor inside or outside the box? Will it be affected by the LED strip?

Program

20 min.

Challenge 2-1: Connect & Explore

	Students will get a UNIHIKER K10 with pre-uploaded project (program 2-1). They should make hardware connections.
	After finishing connection, prompt them to explore the relationship between inputs and outputs observed in their model.

As groups explore, you can encourage them to start using the term input to explain the brightness being detected by the light sensor and output to describe the LED strip’s states when it receives each input.

Example student answer:

Brightness is input detected by the light sensor, the LED strip’s states as outputs.

Challenge 2-2: Modify to show different colors

	Ask groups to load the project (program 2-1) in Mind+, then change the color to red or blue, as these wavelengths provide strong energy to support seedling growth.
	Students need to add one more block to the program so that the LEDs show two different colors.

NOTE: If the LEDs are on, they will affect the light sensor, so it would be ideal to install it somewhere that does not receive light from the LEDs.

Extra Practice

5 min.

Challenge students to create other light patterns using the “Show Color” block. Then have them research common LED fixture types and try to simulate different types on their own.

Next Class: Lesson 3

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