RC robot

Components required:

 1.Hardware components

    

 2.Electronics components

In terms of electronics, you will need the following major components:

Other than the above components, you will need a basic supply of tools, soldering iron, and related stuffs.

Working Logic for the RC Robot Car

Here is a flowchart to help you understand the working logic of the robot car. First we will go over the basic idea of the RC car and the working logic that is involved in the car. There are two blocks, the Transmitter (remote control) and the Receiver (robot car).

On the transmitter side, you have the switches to give the digital inputs to the encoder IC. The encoder then encodes this data and sends it to the the RF Transmitter module.

On the receiver side, you will have the RF Receiver which receives the encoded data and passes it on to the decoder. The decoder decodes the data and sends it to the motor driver IC to drive the motors.

Connections required:

1.Transmitter section:

The HT12E encoder is a 12 bit with 8 address bits and 4 data bits. The address bits can left open or pulled low. In the circuit below, you will see that each of the address pins (A0 to A7) are connected to a switch. So if the switched is ON then that line is connected to GND (Vss) otherwise the pin is left floating.

The TE (transmit enable) is a active low input to the IC. This enables the transmission. So when the switch connected to pin 14 is pressed, the 8 address bits along with the 4 data bits (AD8 to AD11) are serially encoded and sent out at the DOUT pin.

For our application (RC robot car) we will connect TE directly to GND as we have to keep sending the data as and when they arrive to the rc car.

Unlike the receiver circuit, this does not need to have a beefy battery. You could power this circuit with a 9V battery.

2.Receiver section:

This is the circuit diagram for the receiver. It handles the RF reception as well as the the motor drive.

The address pin in the decoder (HT12D) behaves just like that of the the encoder. The data is received at the DIN pin from the RF receiver circuit and then this data is checked 3 times (according to the datasheet the data is transmitted 3 times and received 3 times and only if all 3 times the data is same it is decoded) and then decoded and IC checks if the address pin connection of the encoder is same as that of the decoder. If the address configuration of the decoder matches that in in the received data (from encoder) the data is decoded and latched on to the data pins (D8 to D11).

This decoded data is then send as control signals to the motor driver IC. L293d a dual H-bridge motor driver to be short. It is used to drive the motor in both forward and back ward direction. 

The VT (valid transmit) pin is used to indicate if there is a valid transmission between the encoder and decoder. This pin can be left open or like in the circuit below, an LED with series resistance can be used to give a visual indication.


The final robot will be as follows: