IR remote controlled AC relays

Introduction

Infrared (IR) remote controls are everywhere. Just about every piece of electronic equipment you can think of has one TVs, DVDs, hi-fi systems.Even the latest cameras have them!.

This project is a 3 channel infrared (IR) remote controlled relay driver with power saving. It works with 12-bit SIRC IR signals as used by Sony remote controls.

The controller also features a power save feature which reduces the relay holding voltage to 50% of the relays nominal operating voltage once the relay has switched on.

The board uses Microchip’s pic16f877a microcontroller along with a handful of easy to find components making this possibly the lowest cost remote controlled relay driver around. Everything you need to know to build this project, including the firmware code the project page.

Design-Hardware

IR Remote Controlled AC Relays is consisting of a Remote Controller and Ac Relay Controlling circuit. This design helps to remotely control the speed of a fan or any other relay operated function for electrical or electronic application

IR Remote Controller

IR Remote Controller has Four buttons, an IR transmitter and a Signal Generating Circuit. Three buttons and functions.

ON/OFF – (On or Off the Ac Relay controlling circuit. Once presses keep the Ac Relay controlling circuit ON and if again pressed Ac Relay controlling circuit keep OFF)
Relay 1 Control – (Operate Relay 1. If only Ac Relay Controlling circuit is ON)
Relay 2 Control – (Operate Relay 2. If only Ac Relay Controlling circuit is ON)
Relay 3 Control – (Operate Relay 2. If only Ac Relay Controlling circuit is ON)

Important

This project we used Sony SH TV standard remote controller (Model no:-RM-869)

It works with 12-bit SIRC IR signals as used by Sony remote controls.

In this section first we find the IR signals of SONY SH TV Remote Controller using digital oscilloscope.

Four Significant Signals Generated by the signal generating circuit

AC Relay Controlling Circuit

Schematic Diagram

Final Connecting Diagram

Circuit Description

The board requires a 6 volt DC supply input. The 5 volt supply needed by the microcontroller and the IR receiver.

The relays are switched on by microcontroller via driver transistors (which connected pin 19,20,21). These are low power NPN transistors, in this case BC547 but virtually any small NPN transistor will work here as they only need to switch around 30mA – BC548 or BC549 would also work well. Diodes which connected transistors provide protection for the transistors against the back EMF voltage transient when the relays are switched off.

The controller also features a power saving control which reduces the power consumption of the relays by around 50% when they are on.Relays of the type used here typically need 75% of their nominal voltage to “pull-in”, once on they will ‘hold’ with a lower voltage.

When this transistor is switched on, it provides the full supply voltage to the relays.

LEDs which are connected across the relay coils to give visual indication when the relays are on and can be omitted if not required.

The circuit is controlled by PIC16F877A, PIC available from Microchip. The IR signal is detected and demodulated by TSOP1538 IR receiver IC. This part was chosen because it has a low supply current requirement – typically around 1.5mA. The output from the TSOP1538 is active low, when a signal is received the output goes to 0V, when no signal is received it is pulled high by an internal pull-up resistor. The signal is decoded using the firmware programmed into the PIC16F877A. This has been written to decode the 12-bit SIRC protocol.

Electronic circuit is designed as the power usage is minimized. If only circuit is in ON condition the PIC is allowed to operate Relays. An indicator has been used to identify the state of the controlling circuit and the programme part is developed such that the four signals are identified.

Finally we connected three bulbs to our 3 relays and we supplied the 240v AC supply to relays circuits and we gave the four IR signals to our circuit.

For more information on the SIRC infrared protocol and codes see:

PCB Layout

Component List

You can buy all the parts needed to build this project from most component suppliers world wide.

Component	Description
U	Pic 16F877A
TSOP1538	IR Receicer
X	4Mhz Crystal
C	22pf capacitors
LDEs	Four LEDs
LM7805	power regulator
SW	Push Button
1K Resistors	Five 1k Resistors
D	Three ln4148 diodes
5v/RLY	Three 5V Relys
Q	Three BC 547 Transistors

The Firmware

The MPLAB IDE was used to write down the PIC C code and HI TECH PIC C Compiler used to debugging the code.

Win PIC800 v3.64 was used to program the PIC IC 16F877A for driving AC relay controlling circuit.

Results

In this section first we find the IR signals of SONY SH TV Remote Controller. The following bitmaps are wave forms measured with a digital oscilloscope which the signals were transmitted with a SONY SH remote controller.

After found the four IR signals, we finished designing printed board and finishing our hardware parts. Finally we finish programme part to identify the four signals.

After finished our software and hardware part, we gave the 6v DC supply to our circuit An indicator LEDs has been used to identify the state of the controlling circuit and four indicator LEDs operated with respect to their four IR signals. But, 3 indicator LEDs which connected relays are operate only circuit is ON condition.

Finally we connected 3 bulbs and gave the 240v power to AC relay circuit it can be seen control 3 bulbs with respect to four IR signals.

Construction Photos

Conclusion

In this competitive world human cannot spare his time to perform his daily activities manually without any fail. The most important thing he forgets to switch off the room lights wherever not required. With this, even the power will be wasted up to some extent. This project gives the best solution for electrical power wastage. Also the manual operation is completely eliminated. The industrial appliances can be switched on/off using IR without actually going near the switch boards or regulators. The SONY TV remote used in this project is IR remote.

IR remote acts as the transmitter in this project. When a button is pressed in the remote, the signal will be passed and received by the IR receiver TSOP Receiver. This signal is sent to the microcontroller which decodes the signal and performs the corresponding action in accordance with the button pressed in the remote. For example, if number 1 is pressed in the remote, the switched on/off according to the user requirement.

This project is a 3 channel infrared (IR) remote controlled relay driver with power saving. It works with 12-bit SIRC IR signals as used by Sony remote controls. The board uses Microchip’s PIC16f877A microcontroller.

IR Remote Controller has four buttons, which are ON/OFF button, Relay 1 Controlled button, Relay 2 Controlled button and Relay 3 Controlled button.This project we used Sony SH TV standard remote controller (Model no:-RM-869). It works with 12-bit SIRC IR signals as used by Sony remote controls and we find its four signal using digital oscilloscope.

AC Relay Controlling Circuit is consist of PIC16F877A micro controller, an IR Receiver, LED Indicators (for ON/OFF and for relays), and three Relays mainly. There the electronic circuit is designed as the power usage is minimized. If the circuit is in ON condition the relays are ready to operate according to remote controller signal (the circuit is designed as current flowing of some parts are only at operations). If only circuit is in ON condition the PIC is allow to operate the Relays. An Indicator has been used to identify the states of the Controlling Circuit. And the program is developed such that the three significant signals are identified using the initial point of the signal and sampling points (sampling the signal in small intervals).

Infrared (IR) remote controls are everywhere. Just about every piece of electronic equipment you can think of has one TVs, VCRs, DVDs, hi-fi systems. Even the latest cameras have them!.

Why are they so popular? The answer is simple – convenience. You can change TV channels without leaving your chair. Or adjust the volume on your stereo system. Or, in the case of cameras, be in the photo yourself without having to find someone else to take it.

Code Listing

This code is written using a hitec c, you can download code listing in the attachment menu.

Future Enhancement

Use 9V battery for power supply
Develop device controlled at least 9 channel
Develop device more than safety
Modify surface interface of the device.

Embedded System Laboratory

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Introduction