TCS3200 – Pin Diagram, Circuit and Applications

White light is composed of seven colors. This color spectrum of light is known as VIBGYOR, indicating Violet, Indigo, Blue, Green, Yellow, Orange, and Green. Different colors have different wavelengths. When light falls on the objects, based on the properties of the object, some of the wavelengths get absorbed by the object while some are reflected back. These reflected wavelengths give the color of the object which is detected by the human eye. Combination of wavelengths in different proportions generated different colors. The color sensor is the device which is used to detect color. These sensors can classify the color of the object into either red or blue or green. One of such sensor is TCS3200.

What is TCS3200?

TCS3200 is a programmable color light-to-frequency converter. This module can detect color with the help of microcontroller. It can detect a wide variety of colors like Red, Blue, and Green based on their wavelength. To optimize the sensor readings, frequency scaling is provided.

TCS3200 contains white LEDs to illuminate the object’s surface whose color has to be detected. The intensity of the light reflected back by the object is calculated. A frequency proportional to the intensity is produced by the converter, using which the microcontroller predicts the color of the object.

For detecting different color, filters sensitive to different wavelengths are used. Usually, Red color is detected for wavelength 580nm, Green for wavelength 540nm and Blue for wavelength 450nnm.

Block Diagram of TCS3200

Block-Diagram-of-TCS3200
Block-Diagram-of-TCS3200

TCS3200 is a single monolithic CMOS IC. It consists of configurable silicon photodiodes and a Current-to-frequency converter. Photodiodes are arranged as an 8×8 array. From these photodiodes, 16 photodiodes have a blue filter, 16 photodiodes have a red filter, 16 photodiodes have a green filter and the remaining 16 photodiodes don’t have any filter.

All photodiodes of the same color are connected in parallel. To minimize the effect of non-uniformity of incidence irradiance, four types of photodiodes are interdigitated. All the photodiodes are 110μm×110μm in size.

Circuit Diagram of TCS3200

The output of TCS3200 is a square wave with 50% duty cycle. TCS3200 can be interfaced with any microcontroller directly using digital input and digital output pins. Using two control input pins, the full-scale output frequency can be scaled.

From the four different types of filter covered photodiodes, each diode can be activated using S2 and S3 selection inputs. When the diodes with red filter are chosen, only red incident light is measured and the remaining green and blue light are blocked. Then by measuring the frequency, the intensity of the red light can be detected. Using S0, S1 select inputs, frequency scaling factor can be set.

To measure the frequency, the 6th pin is used. This pin is connected to the microcontroller. To determine the color of the object, first set all the input pins as input and output pins as output. Here there is no use of analog pins. Next set the desired frequency scaling by setting the pins S0, S1 either high or low.

Now to detect the color of the object, activate each type of filter using S2 and S3 selection lines. After activation of filter measure the frequency generated on the 6th pin using a microcontroller. When both S2 and S3 pins are low, Red color filters are activated and the intensity of red components of the object is detected. Similarly, driving S2 low and S3 high detects Blue component and driving both S2, S3 to High detects Green components of the object. All these values are collected and compared to get the actual color of the object. Ambient light can cause variations in the measurements so sensor and object should be protected from the ambient light during measurement.

0.01μF to 0.1μF capacitors should be used for decoupling the power supply lines. For input noise immunity a low impedance electrical connection is required at the device output and device ground. A buffer is required if lines greater than 12 inches are used at the output.

Pin Diagram

Pin-Diagram-of-TCS3200
Pin-Diagram-of-TCS3200

TCS3200 is available in the market as an 8-pin LEAD SOIC package D. Pin description of this module is given below-

  • Pin-1 and Pin-2 are S0, S1 selection lines respectively. These pins are used for frequency scaling.
  • Pin-3, OE, is the output enable pin. This pin is active low.
  • Pin-4, GND, is the ground pin. This pin is the power supply ground.
  • Pin-5, VDD, is the supply voltage pin.
  • Pin-6, OUT, is the output frequency pin. This pin is connected to the microcontroller to read values.
  • PIn-7 and Pin-8 are the S2, S3 selection lines respectively. These pins are used as Photodiode type selection inputs.

Selection line logic for frequency scaling is as below-

  • When both S0, S1 are LOW, the device is in power-down mode.
  • When S0 is LOW and S1 is HIGH, output frequency scaling will be 2%.
  • When S0 is HIGH and S1 is LOW, output frequency scaling will be 20%.
  • When both S0 and S1 are HIGH, output frequency scaling will be 100%.

Specifications

Some of the specifications of TCS3200 are as follows-

  • The main blocks of this module are TCS3200 RGB sensor chip and 4 white LEDs.
  • The four LED’s are given to provide sufficient lighting conditions for the sensor during color detection.
  • TCS3200 chip consists of 8×8 array of photodiodes which can detect red, blue, green colors.
  • This module works on the input supply voltage of 2.7V to 5.5V.
  • Digital TTL interface is present in this module.
  • TCS3200 chip converts light intensity into the frequency with high resolution.
  • This module doesn’t require an ADC to get digital values and can be connected to digital pins of microcontrollers directly.
  • TCS3200 has a programmable color and full-scale output frequency.
  • Power down feature is also given to this module.
  • The operating temperature range of this module is from -40°C to 85°C.
  • TCS3200 contains filters for red, blue, green colors.
  • This module contains a non-linearity error of 0.2% at 50kHz.
  • TCS3200 module has a stable 200 ppm/°C temperature co-efficient.

Applications of TCS3200

Some of the applications of TCS3200 are given below-

  • TCS3200 is used to detect the color of the surfaces.
  • This module finds application in Industries, health care, and manufacturing plants.
  • TCS3200 is applied in medical diagnosis systems.
  • For RGB LED consistency control TCS3200 is used.
  • TCS3200 is applied for industrial process control.
  • In laser edge banding machines to detect color TCS3200 is used.
  • To detect chronic kidney diseases TCS3200 is used for urine analysis.
  • TCS3200 is used in fruit sorting systems.
  • The intensity of blue, red, green radiations can be measured using this sensor module.
  • For classifying different types of metals this module is used.
  • The food industry uses this sensor for sorting of fruits and vegetables.
  • TCS3200 is also used in dental diagnosis and for ammonia detection.
  • For designing of Light-to-Frequency receiver in Multi-color visible light communication, TCS3200 is used.

Alternative IC

Some of the IC that are available in the market that can be used as an alternative to TCS3200 are TCS3400, TCS34715, TCS35727, etc…

It is important to protect the sensor from ambient light, UV radiation, and IR radiation during measurements. This module is also used by engineering students and hobbyists for designing various interesting and easy projects. This sensor is easy to interface with controllers such as Arduino, Raspberry Pi, etc…Further details on the electrical characteristics and layout of TCS3200 can be found in the datasheet. What was the time taken by the TCS3200 module to detect color for your application?

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