TSOP1738 Infrared Sensor Replacements, Working Principle, Advantages and Disadvantages and More
06 December 2023
Ⅱ. Symbol, footprint and pin configuration of TSOP1738
Ⅲ. Features of TSOP1738 infrared sensor
Ⅳ. Working principle of TSOP1738 infrared sensor
Ⅴ. Infrared receiving circuit of TSOP1738
Ⅵ. Technical parameters of TSOP1738 infrared sensor
Ⅶ. Advantages and disadvantages of TSOP1738 infrared sensor
Ⅷ. Applications of TSOP1738 infrared sensor
Ⅸ. Precautions for using TSOP1738 infrared sensor
Infrared signals are widely used in a variety of remote control applications, including remote controls for TVs, air conditioners, stereos and more. This article will introduce the TSOP1738 infrared sensor to help you better understand and use it.
TSOP1738 is a small receiver for infrared remote control systems. The PIN diode and preamplifier are assembled on the leadframe, while the epoxy package acts as an IR filter. The demodulated output signal can be directly decoded by a microprocessor. The TSOP1738 contains an internal photosensitive element, usually an infrared-sensitive photodiode. This photodiode is very sensitive to 38kHz infrared radiation. In addition, it has low power consumption and an easy-to-use package that works well with embedded electronics and can be used with common infrared remote controls.
Replacements and equivalents:
• SM0038
• TSOP-17XX
• TSOP36238
• TSOP4838
The above figure shows the symbol, footprint and pin configuration of the TSOP1738, of which the TSOP1738 has three pins with the following names and descriptions.
Pin 1 (Ground): This pin is only used to share ground with other devices, especially microcontrollers and ICs.
Pin 2 (Vss): This is the power input pin and is used to activate the internal decoder and IR receiver.
Pin 3 (Out): The output pin can be connected to any TTL/CMOS device through a very small resistor.
• TSOP1738 is an active low output device.
• It can be used with any type of TTL/CMOS microcontroller, IC or microprocessor.
• Internal filter provides PCM frequency of analog signal.
• TSOP1738 integrates the infrared receiver and amplifier in one package, reducing the number of components and circuit board space occupation, and improving system integration.
• Even with multiple functions in a single package, the IC has low power consumption and consumes power only during operation. In the standby position, power consumption is significantly reduced.
• Special frequency levels allow the TSOP1738 to operate with specific devices.
• TSOP1738 has an internal band-pass filter, which can effectively avoid interference from ambient light, especially sunlight.
The TSOP1738 consists of a packaged photodetector and signal demodulator whose output can be used directly by a microcontroller. Its working principle involves the reception and demodulation process of infrared rays.
Infrared reception: The TSOP1738 primarily functions as an infrared signal receiver. Ordinarily, infrared remote controls transmit signals in the form of infrared waves, which traverse through the air. Once the receiver detects these infrared signals, the TSOP1738 captures and processes them.
Filtering: TSOP1738 has a built-in specific filter for selecting infrared signals within a specific frequency range. Filters help block interference from other frequencies, ensuring that only signals of a specific frequency emitted by the remote are accepted.
Demodulation: The received infrared signal is modulated at a certain frequency. There is a demodulator inside TSOP1738 to restore the original infrared signal. The demodulation process is to convert the modulated signal into a signal that matches the pulse sequence transmitted by the remote control.
Output: Once demodulated successfully, the TSOP1738 will generate a corresponding voltage pulse on its output pin. The width and frequency of this pulse depend on the modulation characteristics of the received infrared signal.
As shown in the figure, TSOP1738 forms the main component of this circuit and is specially designed to detect infrared signals from any source. It is suitable for detecting signals in the 38 KHz range, so it is called "TSOP1738", and the last two numbers of each series of this TSOP series are named after its reception frequency range.
Vs is connected to the 5v power supply, GND is connected to ground, and the OUT pin is the output terminal. In the event that the TSOP1738 does not detect any IR signal, the circuit provides a high signal as the output. Whenever an infrared signal is incident on the TSOP, the circuit is triggered, causing it to provide a low output. In the above receiver circuit we use this logic to detect the infrared signal.
1. Advantages of TSOP1738
(1) Strong compatibility: It is suitable for a variety of different home electronic equipment such as TV, audio systems, DVD players.
(2) Strong anti-interference ability: It can effectively filter out non-target frequency interference signal, improve system reliability.
(3) Reliable decoding ability: It is able to decode a variety of different infrared signals to ensure accurate reception and response to different commands.
(4) High sensitivity: It has high sensitivity to 38 kHz infrared signals and can receive and decode commands sent by the remote control.
2. Disadvantages of TSOP1738
(1) High power requirements: TSOP1738 needs a stable DC power supply, avoiding the use of AC power.
(2) Slow response speed: Due to the limitation of its working principle, it may not be able to respond quickly to high-speed changing signals.
(3) Only for infrared remote control: It cannot receive other types of wireless signals, such as Bluetooth, radio, etc..
• DVD player remote control
• Security system
• Infrared remote control receiving circuit
• Industrial automation
• Audio system remote control
First, we have to connect TSOP1738 to the circuit correctly and make sure that the output of the receiver is connected to the corresponding microcontroller or other devices. Second, we have to make sure that the operating frequency of the TSOP1738 matches the frequency sent by the IR remote control to ensure proper decoding of the signal. In addition, we should make sure to provide the TSOP1738 with a suitable supply voltage, usually between 3V and 5V. Finally, in order to maintain its regular functioning, it is imperative to prevent the TSOP1738 from being exposed to direct sunlight or intense light sources.
Frequently Asked Questions
1. What is TSOP1738?
TSOP1738 is the standard IR remote control receiver series, supporting all major transmission codes. The sensor can be used for Proximity detection application along with a IR led in robotics and security systems. It receives IR signal at 38khz frequency.
2. What is the equivalent of TSOP1738?
The SM0038 is an alternative to popular TSOP1738 IR receiver.
3. What is the working principle of TSOP1738?
The TSOP1738's main function is to convert IR impulses to electric signals. Every IR receiver operates on a specific frequency. TSOP1738 operates on a 38 kHz IR frequency. It may act owing to a current leakage or other problems if the frequency is higher or lower, but it will not fully perform.
4. How to connect Arduino to TSOP1738?
The connection between Arduino and TSOP1738 is quite easy. You have to connect the VSS pin of the TSOP1738 with the 5V pin and connect the ground pin with the ground pin of the Arduino. At last, connect the output pin of the TSOP1738 with the digital pin 11 of the Arduino.
5. What is the difference between TSOP 1738 and 1838?
TSOP1838/VS1838 is an improved version of popular IR Receiver TSOP1738 and can be directly replaced with this new IR receiver. The TSOP1838 or VS1838 is a miniaturized receivers for infrared remote control systems. PIN diode and pre-amplifier are assembled on lead frame, the epoxy package is designed as IR filter.
