Im using an arduino UNO as receiver and a nano as transmitter.
the fan (in the future is going to be 2 motors) is connected to a H-bridge where one pin sets the direction and the other the speed(PWM). What im going to use it for is controlling an RC car. it was supposed to be a simple project to learn more about data transmission between arduinos and such.
the transmitter is wired like the guide i posted earlier. It only has a small change to add another pot reading (which was already handled by the code, just needed to be added as a new line)
Transmitter code:
#include <VirtualWire.h>
#define POT_TOLERANCE 10 // Noise tolerance level for potentiometers
// this is where i changed from 1 to 2 for the extra potentiometer. the author clearly states that the code supports up to 4
#define POT_NUM 2 // 1 in this case, but a handheld radio has up to 4
// Constants
int potPin[POT_NUM]; // Potentiometer pin numbers
int buttonPin[POT_NUM][2]; // Button pin numbers, each potentiometer has 2 buttons
uint8_t buflen = 3; // Buffer length: 1 letter per channel + a 2 byte reading
// Variables will change:
int buttonState[POT_NUM][2]; // The current reading from the button pins
int lastButtonState[POT_NUM][2]; // The previous reading from the push-button pins
int joystick[POT_NUM]; // Raw potentiometer readings from joystick commands
int trimmer[POT_NUM]; // Trimmer settings
int channelPos[POT_NUM]; // Final channel data to transmit wirelessly
// The following variables are longs because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long lastDebounceTime[POT_NUM][2]; // The last time each output pin was toggled
long debounceDelay = 50; // The debounce time; increase if the output flickers
void setup() {
int c, b;
potPin[0] = A0; // Channel 1 potentiometer on analog A0
potPin[1] = A1; // Channel 2 potentiometer on analog A1
buttonPin[0][0] = 2; // Channel 1 push-button 1 on pin 2
buttonPin[0][1] = 3; // Channel 1 push-button 2 on pin 3
//i don't plan to use the trimmer buttons, so i set them as the same as the other 2, and connect the wires with a 10kohm resisitor to ground
buttonPin[1][0] = 2; // Channel 2 push-button 1 on pin 2
buttonPin[1][1] = 3; // Channel 2 push-button 2 on pin 3
//Iterate over channels and buttons
for(c = 0; c < POT_NUM; c++){
//Set initial states to 0
trimmer[c] = 0;
for(b = 0; b < 2; b++){
lastButtonState[c][b] = LOW;
lastDebounceTime[c][b] = 0;
// Set button pins as inputs
pinMode(buttonPin[c][b], INPUT);
}
joystick[c] = analogRead(potPin[c]); // Get initial joystick reading
}
Serial.begin(9600);
vw_set_tx_pin(4); // Sets pin D4 as the TX pin
vw_set_ptt_inverted(true); // Required for DR3100
vw_setup(4000); // Bits per sec
}
void loop() {
int c, b, potReading, buttonReading;
//Iterate over channels and buttons
for(c = 0; c < POT_NUM; c++){
// Read the joystick position
potReading = analogRead(potPin[c]);
joystick_update(c, &potReading);
for(b = 0; b < 2; b++){
// Read button to update trimmer
buttonReading = digitalRead(buttonPin[c][b]);
trim_update(c, b, &buttonReading);
// Save the readings
lastButtonState[c][b] = buttonReading;
}
}
}
// Helper Functions
void joystick_update(int c, int* potReading){
// Only accept reading if the change is outside noise tolerance level
if(abs(*potReading - joystick[c]) > POT_TOLERANCE){
joystick[c] = *potReading;
pos_update(c);
}
}
void trim_update(int c, int b, int* buttonReading){
// Check to see if you just pressed the button (i.e.
// the input went from LOW to HIGH), and you've waited
// long enough since the last press to ignore any noise:
// If the switch changed, due to noise or pressing:
if (*buttonReading != lastButtonState[c][b]) {
// Reset the debouncing timer
lastDebounceTime[c][b] = millis();
}
if ((millis() - lastDebounceTime[c][b]) > debounceDelay) {
// Whatever the reading is at, it's been there for longer than
// the debounce delay, so take it as the actual current state:
// If the button state has changed:
if (*buttonReading != buttonState[c][b]) {
buttonState[c][b] = *buttonReading;
// Only update trimmer if the new button state is HIGH
if (buttonState[c][b] == HIGH) {
if(b == 0 && channelPos[c] < 1023){
trimmer[c]++;
} else if(b == 1 && channelPos[c] > 0) {
trimmer[c]--;
}
// Update channel position
pos_update(c);
}
}
}
}
void pos_update(int c){
//Update position, send over channel and print data
channelPos[c] = joystick[c] + trimmer[c];
send_message('A'+c,&channelPos[c]); // 'A'+c == konverter bokstav "A" til binær, 65 og legg til C (potensiometer)
Serial.print("Channel: ");
Serial.print(char('A'+c));
Serial.print(" joystick: ");
Serial.print(joystick[c]);
Serial.print(" trimmer: ");
Serial.print(trimmer[c]);
Serial.print(" position: ");
Serial.print(channelPos[c]);
Serial.println("");
}
void send_message(char chanID, int *msg){
//Since the reading is somewhere between 0 and 1023 (from the analog read) and we can only
//send 8-bit packets through VirtualWire's vw_send function, each reading must be split as
//two 8-bit elements and channel ID is sent as a single character, 8-bits large by default.
uint8_t buf[buflen];
buf[0] = chanID; // Label this channel, to distinguish it from other channels
buf[1] = *msg; // Least significant byte (8 bits), rest is truncated from int to uint8_t
buf[2] = (*msg)>>8; // Most significant byte
digitalWrite(13, true); // Flash a light to show transmitting
vw_send(buf, buflen); // Sending the message
vw_wait_tx(); // Wait until the whole message is gone
digitalWrite(13, false); // Turn the LED off.
delay(50); // A short gap.
}
Receiver code:
#include <VirtualWire.h>
//uint8_t bufferMax = VW_MAX_MESSAGE_LEN; // 30 bits
int pspd = 0;
int spd = 0;
int motorBs = 3;
int motorBd = 4;
//sbi(TCCR2A, WGM21); // Change from Phase-Correct PWM to Fast PWM
void setup() {
pinMode(motorBs, OUTPUT); //speed
pinMode(motorBd, OUTPUT); //direction
digitalWrite(motorBd, LOW);
digitalWrite(motorBs, LOW);
Serial.begin(9600);
Serial.println("setup"); // Prints "Setup" to the serial monitor
vw_set_rx_pin(12); // Sets pin D12 as the RX Pin
//vw_set_ptt_inverted(true); // Required for DR3100
vw_setup(4000); // Bits per sec
vw_rx_start(); // Start the receiver PLL running
}
void loop() {
uint8_t recieveBuffer[VW_MAX_MESSAGE_LEN];
uint8_t bufferMax = VW_MAX_MESSAGE_LEN; // no need to make it global
//uint8_t recieveBuffer[bufferMax];
if (vw_get_message(recieveBuffer, &bufferMax)) { // Non-blocking
int i;
digitalWrite(13, true); // Flash a light to show received good message
// Message with a good checksum received, dump it.
Serial.print("Got: ");
for (i = 0; i < bufferMax - 2; i += 3) {
char chanID = recieveBuffer[i]; // Extract channel ID
int c = (recieveBuffer[i + 2] << 8) | recieveBuffer[i + 1]; // Reconstruct 16-bit joystick reading
spd = map(c, 0, 1023, 0, 255);
Serial.print(chanID);
Serial.print(" ");
Serial.print(c);
}
Serial.println("");
digitalWrite(13, false);
}
if (spd != pspd) {
pspd = spd;
Serial.println(spd);
delay(15);
analogWrite(motorBs, spd);
delay(100);
}
}
I have had this problem before using HC-04 ultrasonic range finders and an ir receiver, but if i recall correctly that was a library conflict. (both libraries used the same timer for interrupt)
I feel like i need to specify this more clearly: The code works as long as i dont use a PWM signal. i can use analogWrite 0 and 255 because that is the same as LOW and HIGH.
If set the analogWrite to a pwm signal the code still runs. Its just the RF receiver either not responding or possibly dropping all the messages because of some bug in the library.
i dont know if you are familiar with the VirtualWire library?
