Executing multiple functions/commands on Arduino

Question

I am using an RFduino and an iOS application to control some RGB LEDs.

This is how I'm sending a string command to the module:

- (IBAction)fadeButtonPressed:(id)sender {
 [rfduino send:[@"fade" dataUsingEncoding:NSUTF8StringEncoding]];
}

These command(s) are coming back just fine on the RFduino side:

void RFduinoBLE_onReceive(char *data, int len) {
 if (strncmp(data, "fade", 4) == 0) {
 // begin fading chosen LED colour
 }
}

Is there a better way of executing multiple functions on Arduino? It seems to me that there should be a better way of doing what I'm trying to do.

Originally for example I was getting an issue where the "fade" string was coming back as "fadek" so I used strncmp(data, "fade", 4) instead of strcmp(data, "fade") and this fixed the issue.

I guess I'd like a way of cleaning up my code and perhaps make it easier to introduce new bits of functionality depending on which strings are coming back.

The functions I would like to be able to do would be controlling of the RGB colours and then Fading or Blinking that particular chosen colour.

What if I wanted to introduce faster blinking? Rather than setting another command integer and adding another condition is there a cleaner approach?

The selection of the colours is set by selection of a color wheel within my iOS application. This is working fine. The problem is that the Blinking and Fading does not blink/fade the selected colour (command 0).

Here is my entire sketch so far:

#include <RFduinoBLE.h>
// Pin 2 on the RGB LED.
int rgb2_pin = 2; // red
int rgb3_pin = 3; // green
int rgb4_pin = 4; // blue
int brightness = 0;
int fadeAmount = 5;
// Command properties.
int command = 0;
void setup() {
 // debug output at 9600 baud
 Serial.begin(9600);
 // Setup the LEDs for output.
 pinMode(rgb2_pin, OUTPUT);
 pinMode(rgb3_pin, OUTPUT);
 pinMode(rgb4_pin, OUTPUT);
 // This is the data we want to appear in the advertisement
 // (the deviceName length plus the advertisement length must be <= 18 bytes.
 RFduinoBLE.advertisementData = "rgb";
 // Start the BLE stack.
 RFduinoBLE.begin();
}
void loop() {
 if (command == 1) { // Fade in/out chosen colour.
 analogWrite(rgb2_pin, brightness);
 analogWrite(rgb3_pin, brightness);
 analogWrite(rgb4_pin, brightness);
 // Change the brightness for next time through the loop:
 brightness = brightness + fadeAmount;
 // Reverse the direction of the fading at the ends of the fade:
 if (brightness == 0 || brightness == 255) {
 fadeAmount = -fadeAmount ;
 }
 // Wait for 30 milliseconds to see the dimming effect
 delay(30);
 } else if (command == 2) { // Blink
 digitalWrite(rgb2_pin, HIGH);
 digitalWrite(rgb3_pin, HIGH);
 digitalWrite(rgb4_pin, HIGH);
 delay(200);
 digitalWrite(rgb2_pin, LOW);
 digitalWrite(rgb3_pin, LOW);
 digitalWrite(rgb4_pin, LOW);
 delay(200);
 }
}
void RFduinoBLE_onConnect() {}
void RFduinoBLE_onDisconnect() {}
void RFduinoBLE_onReceive(char *data, int len) {
 Serial.println(data);
 // Each transmission should contain an RGB triple.
 if (strncmp(data, "fade", 4) == 0) {
 command = 1;
 } else if (strncmp(data, "blink", 5) == 0) {
 command = 2;
 } else { // Change colour.
 // Reset other functions.
 command = 0;
 if (len >= 3) {
 // Get the RGB values.
 uint8_t red = data[0];
 uint8_t green = data[1];
 uint8_t blue = data[2];
 // Set PWM for each LED.
 analogWrite(rgb2_pin, red);
 analogWrite(rgb3_pin, green);
 analogWrite(rgb4_pin, blue);
 }
 }
 Serial.println(command);
}

• Handoko: +1 for the way you've posted your question. I hate it when people don't write comments in their script. But you did write comments!

Answer 1

Ended up going with something like this:

#include <RFduinoBLE.h>
// State properties.
int state = 1;
char command;
String hexstring;
// RGB pins.
int redPin = 2;
int grnPin = 3;
int bluPin = 4;
// Setup function to set RGB pins to OUTPUT pins.
void setup () {
 pinMode(redPin, OUTPUT);
 pinMode(grnPin, OUTPUT);
 pinMode(bluPin, OUTPUT);
 // This is the data we want to appear in the advertisement
 // (the deviceName length plus the advertisement length must be <= 18 bytes.
 RFduinoBLE.deviceName = "iOS";
 RFduinoBLE.advertisementInterval = MILLISECONDS(300);
 RFduinoBLE.txPowerLevel = -20;
 RFduinoBLE.advertisementData = "rgb";
 // Start the BLE stack.
 RFduinoBLE.begin();
}
void loop () {
 switch (command) {
 case 1:
 // Blink.
 break;
 case 2:
 // Fade.
 break;
 }
 //RFduino_ULPDelay(INFINITE);
}
// Converts HEX as a String to actual HEX values.
// This is needed to properly convert the ASCII value to the hex
// value of each character.
byte getVal (char c) {
 if (c >= '0' && c <= '9') return (byte)(c - '0');
 else return (byte)(c - 'a' + 10);
}
// Process each function/command.
void processCommand (int command, String hex) {
 switch (command) {
 case 'b':
 command = 1; // Set blink mode.
 break;
 case 'f':
 command = 2; // Set fade mode.
 break;
 case 'c':
 // We put together 2 characters as is
 // done with HEX notation and set the color.
 byte red = getVal(hex.charAt(1)) + (getVal(hex.charAt(0)) << 4);
 byte green = getVal(hex.charAt(3)) + (getVal(hex.charAt(2)) << 4);
 byte blue = getVal(hex.charAt(5)) + (getVal(hex.charAt(4)) << 4);
 // Set the color.
 setColor (red, green, blue);
 break;
 }
}
// Sets the color of each RGB pin.
void setColor (byte red, byte green, byte blue) {
 analogWrite(redPin, red);
 analogWrite(grnPin, green);
 analogWrite(bluPin, blue);
 delay(200);
}
// This function returns data from the radio.
void RFduinoBLE_onReceive (char *data, int len) {
 for (int i = 0; i < len; i++) {
 stateMachine(data[i]);
 }
}
// Main state machine function, which processes
// data depending on the bytes received.
void stateMachine (char data) {
 switch (state) {
 case 1:
 if (data == 1) {
 state = 2;
 }
 break;
 case 2:
 if (data == 'b' || data == 'f' || data == 'c') {
 command = data;
 hexstring = "";
 state = 3;
 } else if (data != 1) { // Stay in state 2 if we received another 0x01.
 state = 1;
 }
 break;
 case 3:
 if ((data >= 'a' && data <= 'z') || (data >= '0' && data <= '9')) {
 hexstring = hexstring + data;
 if (hexstring.length() == 6) {
 state = 4;
 }
 } else if (data == 1) {
 state = 2;
 } else {
 state = 1;
 }
 break;
 case 4:
 if (data == 3) {
 processCommand(command, hexstring);
 state = 1;
 } else if (data == 1) {
 state = 2;
 } else {
 state = 1;
 }
 break;
 }
}

• uniquenamehere: Does the delay(), millis() etc. work on the RFduino?
• gotnull: @Phataas: Not sure, why?
• uniquenamehere: I saw you removed them.
• gotnull: @Phataas: Oh, I just noticed that. I'll add them back in after the analogWrite() calls.