The post explains a circuit which can be used for controlling 1 to 8 appliances with a single RF 433MHz remote control handset. Now you can control fans, lights ACs, oven etc within a range of 50 meters with the same remote.

In a few of my earlier posts I have comprehensively discussed regarding these versatile and outstanding remote control modules, for reference you may want to go through the following links:

Simple RF Remote Control Circuit without Microcontroller ...

RF Remote Control Encoder and Decoder Chip Pinouts Explained ...

Main Features of 433MHz RF Remote Module


The main features of these 433MHz remote modules are:

1) These are available with different ranges, from a single channel to as many as 8 channels, which allows the user to use 8 different appliances from a single receiver unit.

2) The technology used for transmitting the RF waves are extremely sophisticated which prevents the transmitted data from getting hacked.

3) The distance of transmission is also diverse, ranging from 50 meters to 5 kms.

4) Fully customizable "address pins" which enables us to use different remote control handsets with a single receiver unit or vice versa

Although it provides us with the facility to control 8 appliances from a single RF module, as discussed in the feature no#1 above,  this isn't entirely convenient because since all the 8 relays are fixed in the given receiver board could mean a lot of wiring to be done for different appliances situated at different corners of the house.

This slight inefficiency accompanied in the system compels us to think of some alternative method which would allow us to employ individual single relay modules with the desired appliances and then toggle these individual modules through a single remote handset. This option looks much hassle-free as no extra wiring is required for the installations.

Yes, that's what we would be trying to implement by exploiting feature no#4 by customizing the address pinouts of the transmitter module as well as the associated various receiver modules.

Before jumping into the circuit design it would important for us to discuss how these address pins of the transmitter/receiver are related and maybe customized for specific applications.

How Address Pins Function


If you notice the decoder chip of the transmitter module and the encoder chip of the receiver module you will find that both these ICs include 10 address pins (A0 to A9). These address pins are directly compatible with each other, meaning configuration of the transmitter and the receiver address pins should be exactly similar in order to make them respond with each other.

For example suppose if only A0 address pin of the transmitter circuit is connected with ground then the only A0 of the receiver must be connected to ground for enabling the two counterparts to "talk" with each other.

In this proposed article where we are discussing how to control 8 appliances with a single remote control we take the advantage of the above explained "address pin" feature and configure 8 different receiver modules with a single transmitter remote handset.

The following example circuit illustrates the address pin configuration of the relevant Tx and Rx modules. Here we have employed a 4 channel remote module, however a single channel module could also be employed for getting the same results, just by modifying the indicated address pins of the units.

The Receiver Circuit


The following image shows the basic configuration of the receiver module. It shows the remote control application set up for one of the 8 appliances. Similarly, 7 more receiver modules need to built for enabling the control of the associated relevant appliances.

For all the 8 units only the address pins need to be differently configured by simply changing the pin connections with ground, meaning if A0 is connected to ground for the 1st module, then A1 needs to be connected with ground for the 2nd module, A2 for the third module and so on.

Rx Schematic




The IC 4017 section forms the flip flop circuit which ensures latching up of the load in ON and OFF conditions alternately, in response to the remote button press.

The Transmitter Circuit


The following image shows the single remote control transmitter for the 8 separate receiver units as explained above.

Here pressing only the A0 switch activates the above shown receiver unit, since the A0 in the above design is connected with ground, therefore when A0 switch grounds its own A0 pin, both units "shake hands" and the signal is processed for toggling the appliance.

Similarly, switches connected across A1 toA7 can be made compatible with the remaining 7 receiver units for enabling the ON/OFF control of the attached 7 appliances located across different premises.

The diode network associated with the below shown transmitter unit makes sure that the BC557 activates and simultaneously powers the circuit only whenever the relevant switches are pressed, and otherwise the transmitter circuit remains completely switched OFF...this feature allows the battery to last for a very long time.

Tx Schematic





If you any further questions regarding how to control 8 appliances or multiple appliance with single remote, please feel free to ask them through your valuable comments.

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