Getting desperate. Its a really simple program to turn a Led on and Off. I know this has been discussed before, but I couldn't get the right solution, maybe because the topics were dated. Delimiter is changed to 10 in the code and designer. I know the message ON and OFF are sent (checked with a different app) and I use PrintIn to send the message, I ve got a delay in my arduino code. Its an Arduino Uno and the bluetooth is a HC-05. Ive checked on 2 phones, and the same thing happens. Turning on displays, Led turns on, ON is send but no message is received.
void setup() {
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
Serial.begin(9600); // Default communication rate of the Bluetooth module
}
void loop() {
if(Serial.available() > 0){ // Checks whether data is comming from the serial port
state = Serial.read(); // Reads the data from the serial port
}
if (state == '0') {
digitalWrite(ledPin, LOW); // Turn LED OFF
delay (1000);
Serial.println("OFF"); // Send back, to the phone, the String "OFF"
state = 0;
}
else if (state == '1') {
digitalWrite(ledPin, HIGH);
delay (1000);
Serial.println("ON");;
state = 0;
}
}
Dear @Bram_Beers ,
in addition to what @ABG has already said (the terminator must be 10 and not 1), I see several things that can avoid a proper functioning.
Do not use clock1 to periodically verify if the BT is still connected. By forcing a connection periodically it could lead to a stuck of the BT itself and it takes time to reconnect every time the clock fires, thus making the BT comm's with unpredictable latencies.
Therefore, once connected the first time in the AfterPicking event, it is sufficent to perform a handshake instead of forcing a reconnection (but let's see later this feature, for the time being it is not necessary, simply cancel clock1).
Moreover, don't use the ReceiveBytes but the ReceiveText otherwise the string termninator (10) is useless and I guess it won't work with the ReceiveBytes.
On the opposite side, you send the ASCII code for 0 and 1 (48 and 49) but in your arduino code you check for '0' and for '1' which is correct if you transmit a character: '0' and '1'.
Be careful about the check in Arduino: if the app sends '0+linefeed (which is the character 0x0A or 10 in decimal) by checking for an exact equality could not work properly.
Moreover you read() only once, just one character, and the others, if any, will remain in the receiving buffer, so the next read() will fetch the previously "forgotten" character, that most probably is the linefeed; therefore it would be better to do a readstring() so to allow the Arduino code to fetch all the incoming characters until the linefeed.
On the Hardware side: to which pins of your UNO have you connected the HC05 ?
From your code the pins should be connected to pins 0 and1 but this is dangerous because those pins are dedicated to the Serial Monitor, therefore I suggest you to use the SoftwareSerial library instead, that allows you to move the pins towards the HC05 to other pins of the UNO, typically pins 10 and 11 (if free on your board).
Be aware that you shall cross the Tx and Rx pins, i.e. if you set pin 10 as the Rx it shall be connected to the Tx pin of the HC05 and visa versa the Rx to the Tx.
There are plenty of examples in the forum.
Last but not least, to verify the Arduino side, I suggest you to download from the playstore (free) the Serial Bluetooth Terminal (by Kay Morich) app that allows you to be sure that the phone side is working; that app is intended to verify a BT communication and it is working very well on all the phones with any level of Android release. By using this app you can verify if the Arduino is transmitting and receiving properly. When you are done with that you can work again on your app (taking into account @ABG 's and mine hints).
Best wishes for your project (and never give up!)
Hello Bram, you are using the wrong Block to detect data availability. However, you are also trying to detect availability within milliseconds of a connection or even if there is not a connection, none of which will work.
EDIT: You can study the attached to see how to code with "belt and braces" caution.
