October 10, 2019 by Jonathan Miller
Learn how to interface the TCS34725 RGB color detector with a Raspberry Pi Zero and use color in your next project!
They say that colors speak louder than words, but did you know that colors also have their own words and language?
The color RGB and hex is a model representation of red, green, and blue light added together. These give the details of how much red, green, or blue is present in color, while hex is the short representation of RGB. In this tutorial, I’ll show you how to interface the TCS34725 RGB color detector with a Raspberry Pi Zero.
Fig 1. Circuit diagram
The color sensor used in this tutorial’s circuit is an Adafruit TCS34725 color sensor. It has a 3 x 4 photodiode array and four ADC converters to convert the light to photodiode current to a 16-bit digital value.
Raspberry Pi Zero W is set up as a headless Pi. It runs using the Raspbian Lite version OS without the graphical user interface, since the project is mostly using the Raspberry Pi Zero W to process the data gathered without the need of a graphical interface. An LCD 16x2 digital display is used to output the result in lieu of a GUI.
Note: This guide is based on a Raspberry Pi Zero W with a Raspbian headless setup, but can also work with full version of Raspbian OS.
In the project, a headless or screenless setup will be used since we will be using a 16x2 LCD module instead of displaying the output to the display of the Raspberry Pi Zero W.
Before we proceed with interfacing the color sensor and LCD module, there are few steps that need to be done on the Raspberry Pi Zero W.
$sudo apt-get update -y
$sudo apt-get upgrade -y3. Enable the I2C interface by typing the following command in the terminal:
$sudo raspi-configSelect the interfacing option.
Fig 2. Interface Option
Fig 3. Select P5 I2C
Fig 4. Select Yes
Reboot the Raspberry Pi Zero W for these commands to take effect by typing the following command:
$sudo rebootWith the Raspberry Pi Zero W I2C interface enabled, interfacing the Adafruit TCS34725 color sensor using I2C connections is possible.
Fig 5. Adafruit TCS34725
1. For the physical connection of the TCS34725 and Raspberry Pi Zero W, refer to the table below. Note that the Raspberry Pi Zero W must be turned OFF during the connection.
TCS34725 | Raspberry Pi Zero W |
|---|---|
GND | Pin 9 (GND) |
3v3 | Pin 1 (3V3) |
scl | Pin 5 (GPIO3) |
sda | Pin 3 (GPIO2) |
2. Once the connections are done, turn-on and connect again to the device.
3. For this project, Python3 is used. To Install Python3, use the following command:
$sudo apt-get install python3-pip4. Install git to clone libraries.
$sudo apt-get install git5. Clone the library for the Python TCS34725 by inputting the command below on the terminal.
$git clone6. After cloning the library, navigate to the Adafruit_CircuitPython_TCS34725 folder.
$cd Adafruit_CircuitPython_TCS34725Install the setup.py using:
$sudo python3 setup.py installUse the table below to connect the 16x2 LCD module to the Raspberry Pi Zero and Potentiometer.
16x2 LCD Module | Raspberry Pi Zero / Potentiometer |
|---|---|
VSS | GND |
VDD | +5V |
VE | Middle potentiometer pin |
RS | Pin 37 (GPIO 26) |
RW | GND |
E | Pin 35 (GPIO19) |
D0 | - |
D1 | - |
D2 | - |
D3 | - |
D4 | Pin 33 (GPIO 13) |
D5 | Pin 31 (GPIO 6) |
D6 | Pin 29 (GPIO 5) |
D7 | Pin 38 (GPIO 20) |
A+ | +5V |
K- | GND |
7. The library for the LCD module is supported by the GNU/Linux system for the Raspberry Pi, which can be installed locally from PyPI using the command below.
7. The library for the LCD module is supported by the GNU/Linux system for the Raspberry Pi, which can be installed locally from PyPI using the command below.
$sudo pip3 install adafruit-circuitpython-charlcdimport time
import board
import adafruit_tcs34725
import busio
import digitalio
import adafruit_character_lcd.character_lcd as character_lcd
#intializeLCD
lcd_columns = 16
lcd_rows =2
lcd_rs = digitalio.DigitalInOut(board.D26)
lcd_en = digitalio.DigitalInOut(board.D19)
lcd_d7 = digitalio.DigitalInOut(board.D21)
lcd_d6 = digitalio.DigitalInOut(board.D5)
lcd_d5 = digitalio.DigitalInOut(board.D6)
lcd_d4 = digitalio.DigitalInOut(board.D13)
lcd = character_lcd.Character_LCD_Mono(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6,lcd_d7, lcd_columns, lcd_rows)
#initializeColorSensor
i2c = busio.I2C(board.SCL, board.SDA)
sensor = adafruit_tcs34725.TCS34725(i2c)With the TCS34725 color sensor and Pi Zero interfaced, you can start making your own projects to share with the community!
To learn more about how you can use color sensors with other boards, check out these tutorials:
How to Make a Color Sensor Using a TCS3200 Module (uses the PIC16F1516)
Using an RGB sensor with a Raspberry Pi 4 or an Arduino (uses a different RGB sensor, the TCS3200)
I love to explore and make things that incorporate new modules and familiar dev boards. Learning as much as I can to create things I can use!
