TCS34725 Color Sensor User Manual
Version: V1.0.0 Date: 2019.03.21 1 / 16
TCS34725 Color Sensor
User Manual
OVERVIEW
This is a color sensor module based on TCS34725, will output RGB data and light
intensity through the I2C interface. Its advantages include high sensitivity, wide
dynamic range, accurate measuring, etc.
SPECIFICATION
Working voltage：
3.3V/5V
Controller:
TCS34725FN
IO voltage：
3.3V/5V
Interface：
I2C
Dimension：
27 x 20(mm)
INTERFACE
PIN
Description
VCC
3.3V/5V
GND
Ground
SDA
I2C Data Input
SCL
I2C Clock Input
INT
Interrupt Output（Open drain output）
LED
LED
TCS34725 Color Sensor User Manual
Version: V1.0.0 Date: 2019.03.21 2 / 16
CONTENT
Overview ........................................................................................................................................................1
Specification ........................................................................................................................................1
Interface ................................................................................................................................................1
Hardware .......................................................................................................................................................3
Controller ..............................................................................................................................................3
Communication protocol ................................................................................................................3
I2C write ........................................................................................................................................3
I2C Read ........................................................................................................................................4
I2C address ..................................................................................................................................4
How to use ...................................................................................................................................................5
Download examples .........................................................................................................................5
examples ...............................................................................................................................................5
Raspberry Pi.................................................................................................................................5
STM32 ......................................................................................................................................... 10
Arduino ...................................................................................................................................... 12
FAQ ............................................................................................................................................................... 14
TCS34725 Color Sensor User Manual
Version: V1.0.0 Date: 2019.03.21 3 / 16
HARDWARE
CONTROLLER
TCS34725 is used for color sensing. TCS34725 is an I2C bus-based color light-to-
digital converter with IR filter, provides a digital return of red, green , blue (RGB) and
clear light sensing values. The high sensitivity, wide dynamic range and IR blocking
filter make the TCS34725 an ideal color sensor solution for use under varying lighting
conditions and through attenuating materials.
COMMUNICATION PROTOCOL
I2C bus has two lines, one is data line (SDA) and another is lock line (SDL). There are
three kinds of signals when communicating, Start signal, Stop signal and Answer
signal.
Start signal: When SCL is High, SDA change from High to Low, it start to transmit data
Stop signal: When SCL is High, SDA change from Low to High, it stop transmitting.
Answer signal: Every time IC send back a certain Low plus to sender after it receives 8
bits data.
I2C WRITE
TCS34725 Color Sensor User Manual
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When working, Raspberry Pi (hereafter named as Master) will first send a Start signal,
then send a byte to TCS34725(hereafter named as Slaver), whose first 7bits are
address of Slaver and 1 bit write bit. Slave response with Answer signal every time it
receives any data. Master send command register address to Slaver, then data of
command register. Stop signals is sent to slave to stop communicating.
I2C R EAD
When working, Master will first send a Start signal, then send a byte to Slaver, whose
first 7bits are address of Slaver and 1 bit write bit. Slave response with Answer signal
every time it receives any data. Master send command register address to Slave. After
that, Mater will send a Start signal again, and then send a byte (7bits address and 1bit
read bit) to Slaver. Slaver response and send data of the register to Master, master
answer as well. Stop signals will be sent to stop communicating.
I2C ADDRESS
The I2C device address of TCS34725 is 0x29
TCS34725 Color Sensor User Manual
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TCS3472 datasheet page 34
Note: 0x29 is 7bit in fact, therefore, when you set the I2C address, you should left-shift
one bit, turn it to 0x52
HOW TO USE
DOWNLOAD EXAMPLES
Find and download examples from Waveshare wiki:
Extract the 7z you get:
Arduino: examples for Arduino
Raspberry Pi: examples for Raspberry Pi(wiringPi, python, bcm2835)
EXAMPLES
RASPBERRY PI
Insert the SD card (Raspbian installed)
TCS34725 Color Sensor User Manual
Version: V1.0.0 Date: 2019.03.21 6 / 16
Copy the Raspberry Pi examples to SD card:
Insert SD card to Raspberry Pi and power on, you can find the folder is listed in /boot
Copy the examples to /home/pi and change its permission:
INSTALL LIBRARIES
To run the examples, you need to first install libraries (wiringPi, bcm2835 and python)
and enable I2C interface, otherwise example cannot work properly.
BCM2835
http://www.airspayce.com/mikem/bcm2835/
Download the library from bcm2835 libraries and install:
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.58.tar.gz
sudo tar zxvf bcm2835-1.xx.tar.gz
TCS34725 Color Sensor User Manual
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cd bcm2835-1.xx
sudo ./configure
make
sudo make check
sudo make install
Note: The xx is the version number you download, for example, if the version you
download is bcm2835-1.52. then the command you should execute is sudo tar zxvf
bcm2835-1.52.tar.gz
wiringPi libraries:
sudo apt-get install git
sudo git clone git://git.drogon.net/wiringPi
cd wiringPi
sudo ./build
Python libraries:
sudo apt-get install python-pip
sudo pip install RPi.GPIO
sudo pip install spidev
sudo apt-get install python-imaging
sudo apt-get install python-smbus
Enable I2C interface:
sudo raspi-config
TCS34725 Color Sensor User Manual
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Reboot Raspberry Pi and check I2C devices:
sudo reboot
i2cdetect -y 1
HARDWARE CONNECTION
TCS34725 Color Sensor User Manual
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TCS34725 Color Sensor
Raspberry Pi
VCC
3.3V
GND
GND
SDA
SDA
SCL
SCL
INT
17
LED
18
RUNNING EXAMPLE
BCM2835 example
cd bcm2835
sudo ./main
WiringPi example
cd wiringpi
sudo ./main
python example
cd python
sudo python main.py
Note: If you get error information that files are not exist when running BCM2835 or
wiringpi example, please execute make command and try again.
EXPECTED RESULT
TCS34725 Color Sensor User Manual
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The expected result of three examples are similar, here we take python codes as
example:
R, G, B value are printed in RGB888 format (DEC), C is light value without processing,
RGB565 and RGB888 are HEX data printed in certain format. LUX is light value
processed. CT is color temperature. (https://en.wikipedia.org/wiki/Color_temperature)
If you want to measure CT, please turn off LED. INT is interrupt, 1: light value is over
threshold.
You can turn the RGB value to color with tools below:
https://www.waveshare.com/w/upload/5/53/Infrared-Temperature-Sensor-Code.7z
STM32
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Open STM32 project with Keil uVision5. The example is based on HAL libraries.
Development board used is Waveshare XNUCLEO-F103RB, the chip is
STM32F103RBT6. Example uses UART2 (PA2, PA3) to print data, 115200, 8N1.
HARDWARE CONNECTION
TCS34725 Color Sensor
STM32
VCC
3.3V
GND
GND
SDA
SDA/D14/PB9
SCL
SCL/D15/PB8
INT
D8/PA9
LED
PWM1/D9/PC7
EXPECTED RESULT
This is the output when testing red
You can turn the RGB value to color with tools below:
https://www.waveshare.com/w/upload/5/53/Infrared-Temperature-Sensor-Code.7z
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ARDUINO
The development board used is Waveshare UNO PLUS(Compatible with Arduino
UNO ), set serial monitor to 115200
HARDWARE CONNECTION
TCS34725 Color Sensor
Arduino
VCC
3.3V/5V
GND
GND
SDA
SDA
SCL
SCL
INT
D8
LED
D9
EXPECTED RESULT
This is the output when testing red
TCS34725 Color Sensor User Manual
Version: V1.0.0 Date: 2019.03.21 13 / 16
You can turn the RGB value to color with tools below:
https://www.waveshare.com/w/upload/5/53/Infrared-Temperature-Sensor-Code.7z
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FAQ
1. Q: Raspberry Pi example initializing failed?
A: Please check if you connect sensor correctly, and check i2C device with
command i2cdetect -y 1
Please correct connecting and restart
2. Q: What happened when running example by mistake?
A: If you find that python or bcm2835 examples cannot work properly after
running wiringpi codes, please just restart Raspberry Pi can test again
3. Q: Data output are incorrect when using STM32 and Arduino examples?
A: Please check if you choose the correct COM port (according to device manager).
If all the setting are correct, please exchange RXD and TXD and try again.
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4. Q: Why the RGB data outputted are all 0
A: Please check if you connect device correctly then press reset button
5. Q: The RGB data output are all 253?
A: The light intensity value is over measure range, you can try to modify the gain
parameter in initial codes, or add statement
TCS34725_Set_Gain(TCS34725_GAIN_16X)） following initialize part.
6. Q: Color detect is abnormal after modifying integrate time
A: The integrate time is relate to maximum data of RGB channels. If the color turns
darker or lighter after modification, please try to change the brightness of LED
7. Q: Why interrupt cannot be triggered or be triggered all the time after modifying
integrate time
TCS34725 Color Sensor User Manual
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A: Interrupt is relate to data of Clear channel. Data of Clear channel is influenced
by integrate time. When gain is 60:
Integrate time
Max value of Channel
2.4ms
1024
24ms
10240
50ms
5400
101ms
21504
154ms
65535
700ms
65535
Therefore, you should modify the threshold value if sample rate is fast. And please
increase brightness of LED when you set integrate time to 2.4ms.
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