What you need to know to make radio control cars work well

The radio control cars models are impressive. Their radios include wireless solutions. Most often, references are TLP434A and RLP434A, which are the transmitter and receiver respectively. This game works through a radio carrier signal and 434MHz ASK modulated, so that they can transmit logic values 1 and 0.

ASK modulation is similar to the modulation of AM commercial radio AM band. In ASK modulation logic 0 is represented by the absence of the carrier signal and logic 1 in the presence of this.

The radio control cars radio modules used in this project have a range of 100 meters if they have a proper installation of the antennas. ASK modulation as AM modulation is extremely prone to interference and noise. It is therefore important to implement within the PIC programming routine to detect when an error has come up with data to be discarded, since no radio modules include any software or hardware method for detecting these errors.

These radio modules are able to transmit at 9600 bits per second and to receive a rate of 4800 bits per second but these are extreme cases of the modules. To establish a reliable communication, we will work at a rate of 2400 bits per second.

The installation of these modules is very simple radio, two pins are used to power the module, each one with VCC and GND, a pin for the antenna and one for data input or output serially. The transmitter can be powered with a voltage of between 3V and 12V. The transmission power is greater at higher voltage. The receiver module can be powered only 5V.

Implementation

To establish communication between the PIC USART module work with each of the microphones. This implies that one of them is the transmitter and the other micros receptor. In addition, TX and RX are among top systems. In TX micro four pins are continually evaluated, which are installed in two separate buttons that are the four bits of information we want to convey. This radio control cars circuit’s information is packaged and transmitted serially by the USART.

To avoid errors in the data arrival, it is necessary to implement some method to ensure the accuracy of the information. For this there are complex forms of error control but for this project will implement a very simple method known as redundancy, which is good to transmit the same radio control cars data repeatedly and verify if the data that arrives at the micro RX is equal to determine if the data has no errors.