Configuration 4: RF Remote Robot

Wireless experiment

Configuration 4: RF Remote Robot

Compare Bluetooth and RF control with a simple command receiver.

The RF remote robot introduces radio control. Because RF modules differ, students learn to identify pinout, frequency, transmitter pairing, and decoding method.

What students learn: Wireless comparison, signal reading, and module documentation skills.

Read this before wiring: The schematic shows only the modules required for this configuration. Compare it with the Arduino program pins before connecting the battery.

Mode-specific circuit schematic

Pin and power rules

Power rule

Use the Li-ion pack for motor power through L293D VCC2, and regulated 5V for Arduino Nano logic and modules.

Ground rule

All grounds must be common, otherwise the Arduino signal has no reliable reference.

Pin rule

The Arduino programs on this page match this pin plan: D5/D6 PWM, D8-D11 motor direction, D2-D3 Bluetooth, D4/D7 ultrasonic, D12 servo, A0-A5 sensors/RF.

Step-by-step build

Confirm the RF module type and matching transmitter.
If using a decoder board, connect forward/back/left/right outputs to Nano inputs.
Keep Bluetooth disconnected during RF tests.
Add the correct antenna length for the RF module.
Compare range and reliability with Bluetooth.

Arduino Nano program

Download HEX

// Arduino Nano RF Remote Rover - simple digital command receiver example
// Use RF receiver output pins or a decoder board with F/B/L/R channels.
const int rfF = A2, rfB = A3, rfL = A4, rfR = A5;
const int ENA = 5, IN1 = 8, IN2 = 9, ENB = 6, IN3 = 10, IN4 = 11;

void setup() {
  pinMode(rfF, INPUT); pinMode(rfB, INPUT); pinMode(rfL, INPUT); pinMode(rfR, INPUT);
  pinMode(ENA, OUTPUT); pinMode(IN1, OUTPUT); pinMode(IN2, OUTPUT);
  pinMode(ENB, OUTPUT); pinMode(IN3, OUTPUT); pinMode(IN4, OUTPUT);
}

void loop() {
  if (digitalRead(rfF)) forward(150);
  else if (digitalRead(rfB)) backward(150);
  else if (digitalRead(rfL)) left(150);
  else if (digitalRead(rfR)) right(150);
  else stopMotors();
}

void forward(int s){ drive(HIGH,LOW,HIGH,LOW,s); }
void backward(int s){ drive(LOW,HIGH,LOW,HIGH,s); }
void left(int s){ drive(LOW,HIGH,HIGH,LOW,s); }
void right(int s){ drive(HIGH,LOW,LOW,HIGH,s); }
void stopMotors(){ analogWrite(ENA,0); analogWrite(ENB,0); }
void drive(int a1,int a2,int b1,int b2,int s){
  digitalWrite(IN1,a1); digitalWrite(IN2,a2);
  digitalWrite(IN3,b1); digitalWrite(IN4,b2);
  analogWrite(ENA,s); analogWrite(ENB,s);
}

Use Build here to verify this program with the Roboda Arduino compiler.

Do and don't

Use Arduino Nano as the controller.
Keep battery negative and all module GND pins connected.
Test motors with wheels lifted first.
Use a voltage divider for HC-05 RX if Arduino TX is 5 V.
Power servo from a stable 5 V source.

Don't

Do not short Li-ion cells.
Do not connect motors directly to Arduino Nano pins.
Do not mix loose wires without labels.
Do not run high motor speed during first tests.
Do not assume every RF module has the same pinout.

Configuration 4: RF Remote Robot