Grove Sunlight Sensor with Si1145 and Arduino/Platform IO

Introduction

For hydroponics systems, every plant has preferences on how long they want sunlight per day. Some are 12 hours and others are 8 hours. This time, we would like to measure UV-light, visible light, and infrared light and check the growth.

Seeed (a hardware company) provides a Grove – Sunlight sensor (weblink). So, I would like to show how this sunlight sensor can be developed with our hydroponics system.

Hardware Specification

This sunlight sensor comes with SI1145 from SiliconLabs. It is a reflectance-based infrared proximity, UV index, and ambient light sensor.

The interface with the hardware is I2C.

Software Guide

Platform IO has Grove – Sunlight Sensor library.

Useful Header file and APIs – Arduino IDE: File > Examples > Grove_Sunlight_Sensor>SI1145DEMO

• Header File
  • SI114x.h
• Object Instantiation
  • SI114X SI1145 = SI114X();
•  APIs
  • SI1145.Begin()
  • SI1145.ReadVisible()
  • SI1145.ReadIR()
  • SI1145.ReadUV
    • real_UV = ((float)SI1145.ReadUV() / 100 )

Lab Test

This sensor can output three information

1. Visible Light
2. Infrared (IR) Sensor
3. UV light index: UV in mW per area
   • 0 to 2: Low UV
   • 3 to 5: Moderate
   • 6 to 7: Hight
   • 8 to 10: Very High
   • 11 or more: Extreme

When just a room light is on,

When the hydroponic light is on,

Reference

Grove Sunlight Sensor wikipage: weblink