Remote Control Power Switches

Content by:- Jayashan Bandara | Written by:- Mihiri Mandeera

Introduction

We use power switches on a daily basis. It might be challenging to turn power switches on and off all the time. As a remedy, we can use a remote controller to turn these switches on and off automatically.

We will use the remote controller to turn on and off power switches in this project.

Radio signals are used to maintain the connection between the remote control and the power switches in this case.

Figure 1.1 summarizes the procedure that occurs here.

For delivering radio signals, we employ a 433MHz frequency module, as shown in Figure 1.2.

Figure 1.2

So, we can define four sub systems in our project

• Remote controller
• RF transmitter
• RF receiver
• Power switches

Rf Transmitter

A radio signal with a frequency of 433MHz is transmitted to the rf receiver. The transmitter is shown in figure 2.1. The transmitter is powered by the two Vcc and Gnd pins. The data pin is used to power the data transmitter. This data pin is used to transmit encoded signals.

• Max range with the antenna in normal Conditions: 100 Meters
• TX Supply Voltage: 3V ~ 6V
• TX Output Power: 4 ~ 12 Dbm

Figure 2.1

Remote Controller

 As previously stated, the signal is encoded using an encoder. The encoder in this case is the Ht12e encoder IC. Figure 3.1 depicts its configuration.

Figure 3.1

What is important for us here are pins A0-A7 and AD0-AD3. This encoder is a 12bit encoder. But here 8 bits are used for the address. We can send the signal between an encoder and a decoder similar to the address. The other 4 bit is used to transmit data. So, we can control 4 switches here. Here we use 0b00000000 for the address. So, we keep the pins from A0-A7 to low value. We can accomplish this by connecting these pins to the Gnd.

Figure 3.2

The encoder is connected as shown in Figure 3.2. Pins AD0-AD3 can be utilized as a remote controller for power switches.

As shown in Figure 3.3, we can link the transmitter and the ht12e encoder IC.

Figure 3.3

RF Receiver

The data signal emitted by the RF transmitter is captured here. This module has four pins. Both the Vcc and Gnd pins are used to provide the required power to the module as well as the transmitter. The remaining two pins can be used as data pins.

Figure 4.1 represents the pins of the RF receiver

Figure 4.1

• Max range with the antenna in normal Conditions: 100 Meters
• RX Receiver Frequency: 433 MHz
• RX Typical Sensitivity: 105 Dbm
• RX Supply Current: 5 mA
• RX IF Frequency: 1MHz
• RX Operating Voltage: 5V

The data pin here can receive the data signal emitted by the RF transmitter. But since it is encoded, it needs to be decoded. For that we use Ht12d decoder. For that we use Ht12d decoder.

Power Switches

Figure 5.1

We must use the same address that we used in encoder, as indicated in the remote controller section. In this case, the address 0b00000000 should be utilized. As an encoder IC Ht12e, The AD0-AD7 pins are connected to the gnd. Connect the encoded 12 bit (IN) of the Ht12d decoder IC to the receiver’s data pin, as shown in Figure 5.2.

Figure 5.2

The data signal from the receiver can be decoded after connected as described above. Then we can utilize the remote controller’s four-bit signal to control four switches.

These signals can be used as follows.

We can control the switches independently this way. For example, if we simply wish to activate AD0, we may transmit this four-bit signal.

In the above way we can connect pins D0, D1, D2, D3 of Ht12d to power switches and control the power switches from pins AD0, AD1, AD2, AD3 in encoder.

However, as power switches require 230 volts, we must insert a 5 volt relay and a TIP41C transistor between the Ht12d output pins and the power switches. It is possible to connect it as follows.