Infra Red Remote Control

Description: This circuit is the result of research conducted by Andy Collinson. It employs a photodiode, specifically the SFH2030, as an infrared sensor. A MOSFET operational amplifier, CA3140, is utilized in differential mode to amplify the current pulses generated by the photodiode. An ordinary colored LED (LED1) illuminates when infrared radiation is detected. The output from the operational amplifier, pin 6, can be connected to a multimeter set to read DC volts. This allows for the comparison of infrared remote control strengths based on the meter reading; a higher reading indicates a stronger infrared light. The researcher aimed different remote controls at the sensor from approximately 1 meter away during the comparison of results. For every microamp of current through the photodiode, about 1 volt is produced at the output. It should be noted that a 741 or LF351 operational amplifier will not function in this circuit. Although a 12-volt power supply has been used, a 9-volt battery is also suitable for this application.

This circuit design effectively demonstrates the principles of infrared detection and amplification. The SFH2030 photodiode serves as the primary sensor, converting infrared light into an electrical current. The CA3140 operational amplifier, configured in differential mode, enhances the sensitivity of the circuit by providing necessary amplification of the small currents generated by the photodiode.

The output voltage from the op-amp is directly proportional to the current detected by the photodiode, making it easy to quantify the strength of incoming infrared signals. The inclusion of an LED provides a visual indication of infrared detection, allowing for straightforward operation without the need for additional diagnostic equipment.

For practical implementation, the circuit can be powered by either a 12-volt power supply or a 9-volt battery, providing flexibility for various applications. The choice of operational amplifier is critical; standard op-amps like the 741 or LF351 are unsuitable due to their inadequate response characteristics for this specific application.

In summary, this circuit is a valuable tool for measuring infrared signal strength, useful in applications such as remote control testing and infrared communication analysis. The design's simplicity, combined with effective performance, makes it a suitable project for both educational purposes and practical applications in electronics.This circuit is the result of Andy Collinson research. He has used a photodiode, SFH2030 as an infra red sensor. A MOSFET opamp, CA3140 is used in the differential mode to amplify the pulses of current from the photodiode. LED1 is an ordinary coloured led which will light when IR radiation is being received. The output of the opamp, pin 6 may be c onnected to a multimeter set to read DC volts. Infra red remote control strengths can be compared by the meter reading, the higher the reading, the stronger the infra red light. He aimed different remote control at the sensor from about 1 meter away when comparing results. For every microamp of current through the photodiode, about 1 volt is produced at the output. A 741 or LF351 will not work in this circuit. Although he has used a 12 volt power supply, a 9 volt battery will also work here.