5 channel radio remote control

This article discusses a simple five-channel radio remote control circuit utilizing the TX-2B and RX-2B integrated circuits from Silan Semiconductors. The TX-2B/RX-2B is a remote encoder-decoder pair suitable for remote control applications. It features five channels, a wide operating voltage range (from 1.5V to 5V), low standby current (approximately 10µA), low operating current (2mA), an auto power-off function, and requires minimal external components. Originally designed for remote toy car applications, the TX-2B/RX-2B can be adapted for various remote switching applications. The TX-2B serves as the main component of the circuit. Push-button switches S1 to S5 activate the corresponding output channels in the receiver/decoder circuit. These switches interface with the built-in latch circuitry of the TX-2B. Resistor R7 determines the frequency of the TX-2B's internal oscillator. Resistor R1 and Zener diode D1 create a simple Zener regulator circuit, supplying the IC with 3V from a 9V main supply. Capacitor C2 acts as a filter capacitor, while C1 serves as a noise bypass capacitor. Diode D2 functions as a power-on indicator LED, with resistor R6 limiting the current through the LED. Switch S1 acts as the ON/OFF switch. The encoded control signal is available at pin 8 of the IC, which does not include the carrier frequency. This signal is directed to the next stage of the circuit, a radio transmitter. Crystal X1 establishes the oscillator frequency of the transmitter section. Resistor R2 serves as the biasing resistor for Q1, while R3 limits the collector current of Q1. The encoded signal is coupled to the collector of Q1 through capacitor C3 for modulation. Transistor Q2 and its associated components provide additional amplification to the modulated signal. The remote receiver circuit is based on the RX-2B IC. The initial part of the circuit is a radio receiver utilizing transistor Q1. The received signal is demodulated and sent to pin 14 of the IC, which is the input for the built-in inverter within the IC. Resistor R2 sets the frequency of the IC's internal oscillator. Output pins O/P 1 to O/P 5 are activated in correspondence to the push buttons S1 to S5. Zener diode D1 and resistor R12 create a basic Zener regulator to supply the RX-2B with 3V from the 9V main supply. Capacitor C12 serves as a filter capacitor, while R11 limits current for the radio receiver section. Diode D2 protects the circuit from accidental polarity reversals. Capacitor C15 is another filter capacitor, and capacitor C14 acts as a noise bypass capacitor.

The circuit design integrates a comprehensive approach to remote control functionality, leveraging the TX-2B and RX-2B ICs for effective communication. The TX-2B module is responsible for encoding control signals from the push-button switches, with the internal oscillator frequency set by resistor R7 to optimize transmission efficiency. The Zener diode D1 ensures stable voltage supply to the TX-2B, preventing fluctuations that could disrupt operation. The modulation process, facilitated by transistor Q1 and capacitor C3, ensures that the encoded signal is effectively transmitted over radio frequencies, enhancing the range and reliability of the control system.

In the receiver section, the RX-2B demodulates incoming signals, with the output states corresponding to the activation of the respective push buttons. The circuit's robustness is further enhanced by the inclusion of various filtering capacitors and protection diodes, ensuring longevity and reliability in diverse operating conditions. The design is versatile, allowing adaptation for various applications beyond toy controls, such as home automation systems, remote lighting, and other remote switching tasks, making it a practical solution for numerous electronic projects.This article is about a simple 5 channel radio remote control circuit based on ICs TX-2B and RX-2B from Silan Semiconductors. TX-2B / RX-2B is a remote encoder decoder pair that can be used for remote control applications. TX-2B / RX-2B has five channels, wide operating voltage range (from 1. 5V to 5V), low stand by current (around 10uA), low opera ting current (2mA), auto power off function and requires few external components. The TX-2B / RX-2B was originally designed for remote toy car applications, but they can be used for any kind of remote switching application. The TX-2B forms the main part of the circuit. Push button switches S1 to S5 are used for activating (ON/OFF) the corresponding O/P channels in the receiver / decoder circuit.

These push button switches are interfaced to the built-in latch circuitry of the TX-2B. Resistor R7 sets the frequency of the TX-2B`s internal oscillator. Resistor R1 and Zener diode D1 forms a simple Zener regulator circuit for providing the IC with 3V from the 9V main supply. C2 is the filter capacitor while C1 is a noise by-pass capacitor. D2 is the power on indicator LED while R6 limits the current through the same LED. S1 is the ON/OFF switch. The encoded control signal will be available at pin 8 of the IC. The encoded signal available at pin 8 is without carrier frequency. This signal is fed to the next stage of the circuit which is a radio transmitter. Crystal X1 sets the oscillator frequency of the transmitter section. R2 is the biasing resistor for Q1 while R3 limits the collector current of Q1. The encoded signal is coupled to the collector of Q1 through C3 for modulation. Transistor Q2 and associated components provide further amplification to the modulated signal. The remote receiver circuit is built around the IC RX-2B. The first part of the circuit is a radio receiver built around transistor Q1. The received signal is demodulated and fed to pin 14 of the IC. Pin 14 is the input of the built in inverter inside the IC. R2 sets the frequency of the IC`s internal oscillator. O/P 1 to O/5 are the output pins that are activated corresponding to the push buttons S1 to S5. Zener diode D1 and resistor R12 forms an elementary Zener regulator for supplying the RX-2B with 3V from the 9V main supply.

C12 is the filter capacitor while R11 is the current limiter for the radio receiver section. Diode D2 protects the circuit from accidental polarity reversals. C15 is another filter capacitor and C14 is a noise by-pass capacitor. 🔗 External reference