Hi,
i have 434MHz receiver and transmittter module and i want to control motor by using RF. i wrote down the code by using virtualwire library. On the transmitter side i take the values from the potentiometer and transmit the receiver side. then, receiver get this potentiometer value, and it converts pwm signal by using analogWrite function. on the receiver side i also have L293D motor driver unit. when i transmit the message, i get the right value (i am using the serial.print function for debug). up to this point everything seems right.
now, i set up the potentiometer value as its maximum (which is 1023) and i decrease it slowly up to aprox. 1000, i get the right value at the motor output from the L293d. however if i continue decreasing, the motor output voltage suddenly drops to 0.
i cant find the solution. any idea?
TRANSMITTER CODE
#include <VirtualWire.h>
const int led_pin = 11;
const int transmit_pin = 12;
// const int receive_pin = 2;
// const int transmit_en_pin = 3;
const int buttonPin = 8;
const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
int sensorValue; // value read from the pot
char sensorTransmit[5];
void setup() {
// Initialise the IO and ISR
vw_set_tx_pin(transmit_pin);
// vw_set_rx_pin(receive_pin);
// vw_set_ptt_pin(transmit_en_pin);
// vw_set_ptt_inverted(true); // Required for DR3100
vw_setup(2000); // Bits per sec
pinMode(buttonPin, INPUT);
Serial.begin(9600);
Serial.print("Setting Up...");
}
void loop() {
// read the analog in value:
sensorValue = analogRead(analogInPin);
itoa(sensorValue,sensorTransmit,10); // Convert integer data to Char array directly
if (digitalRead(buttonPin) == HIGH)
{
digitalWrite(led_pin, HIGH); // Flash a light to show transmitting
vw_send((uint8_t *)sensorTransmit, strlen(sensorTransmit));
vw_wait_tx(); // Wait until the whole message is gone
digitalWrite(led_pin, LOW);
delay(10);
// DEBUG
Serial.print("Sensor Value: ");
Serial.print(sensorValue);
Serial.print(" Sensor Transmitted: ");
Serial.print(sensorTransmit);
Serial.println(" ");
delay(10);
// END DEBUG
}
}
RECEIVER CODE
/*
The circuit:
* Receiver:Vcc=5V,data-data short and data=pin11,GND
*/
#include <VirtualWire.h>
//Receiver Pins Assingment
const int led_pin = 2;
// const int transmit_pin = 12;
const int receive_pin = 6;
// const int transmit_en_pin = 3;
//Now Motor Control Pins Assignment
int Motor1Pin1 = 5;
int Motor1Pin2 = 9;
int Motor2Pin1 = 10;
int Motor2Pin2 = 11;
// int potPin = A0; We receive this data directly from transmitter
int potValue = 0;
int motorValue = 0;
//Receiver Analog Assignments
int sensorData;
char sensorReceive[5];
void setup()
{
//delay(1000); You can put delay
Serial.begin(9600); // Debugging only
Serial.println("Setting Up...");
// Initialise the IO and ISR
// vw_set_tx_pin(transmit_pin);
vw_set_rx_pin(receive_pin);
// vw_set_ptt_pin(transmit_en_pin);
// vw_set_ptt_inverted(true); // Required for DR3100
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver PLL running
}
void loop()
{
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;
if (vw_get_message(buf, &buflen)) // Non-blocking
{
int i;
digitalWrite(led_pin, HIGH); // Flash a light to show received good message
// Message with a good checksum received, print it.
for (i = 0; i < buflen; i++)
{
sensorReceive[i] = char(buf[i]);
/*Serial.print(buf[i], HEX);
Serial.print(' ');*/
}
// Null terminate the char array
// This needs to be done otherwise problems will occur
// when the incoming messages has less digits than the
// one before.
sensorReceive[buflen] = '\0';
// Convert Sensor1CharMsg Char array to integer
sensorData = atoi(sensorReceive);
// DEBUG
Serial.print("Sensor Data: ");
Serial.println(sensorData);
// END DEBUG
// Serial.println();
digitalWrite(led_pin, LOW);
potValue = sensorData;
motorValue = map(potValue, 0, 1023, 0, 255);
Serial.print("Potentiometer = " );
Serial.print(potValue);
Serial.print("\t motor = ");
Serial.println(motorValue);
delay(2);
GoForward();
delay(10);
/* GoBackward();
delay(2000);
GoRight();
delay(2000);
GoLeft();
delay(2000);
Stop();
delay(2000); */
}
}
void GoForward(){
analogWrite(Motor1Pin2, LOW);
analogWrite(Motor1Pin1, motorValue);
analogWrite(Motor2Pin2, LOW);
analogWrite(Motor2Pin1, motorValue);
}
/*
void GoBackward(){
analogWrite(Motor1Pin1, LOW);
analogWrite(Motor1Pin2, motorValue);
analogWrite(Motor2Pin1, LOW);
analogWrite(Motor2Pin2, motorValue);
}
void GoLeft(){
analogWrite(Motor1Pin1, LOW);
analogWrite(Motor1Pin2, motorValue);
analogWrite(Motor2Pin2, LOW);
analogWrite(Motor2Pin1, motorValue);
}
void GoRight(){
analogWrite(Motor1Pin2, LOW);
analogWrite(Motor1Pin1, motorValue);
analogWrite(Motor2Pin1, LOW);
analogWrite(Motor2Pin2, motorValue);
}
void Stop(){
analogWrite(Motor1Pin2, LOW);
analogWrite(Motor1Pin1, LOW);
analogWrite(Motor2Pin1, LOW);
analogWrite(Motor2Pin2, LOW);
}
*/
it works only when is potetiometer at its max. value which is 1023.