Revesed question mark

theflyingoreo · June 18, 2017, 12:03am

So I recently got my first Arduino and I wanted to follow a simple tutorial to get my feet wet. I'm following this tutorial exactly:

However, any time I press a button in the app, the only thing that prints out in the Serial Monitor is a reverse question mark

[Album] imgur.com

The LEDs don't turn on at all. I went to the Arudino code to try and debug the issue. When I print the "inSerial", it's just an empty string. Printing "inStr" in the Check_Protocol function throws that backwards question mark. I'd appreciate any help I could get because I can't understand why it's doing this

Power_Broker · June 18, 2017, 12:26am

Sounds like a baud issue, but I could be wrong.

theflyingoreo · June 18, 2017, 12:32am

I'm using an HC 06 module and in the setup() function, Serial.begin(9600) is called. Shouldn't that rule out any baud issues?

Edit: I tried running AT commands using the Serial Monitor in the Arduino IDE. When I type "AT" and click Send, nothing happens. I assume this is a problem, right?

Sorry about the n00b questions

TomGeorge · June 18, 2017, 12:55am

Hi,
What baud rate have you got the monitor set at?

In the bottom right hand side of the monitor screen you can set the rate.

It should be the same as the arduino, ie Serial.begin(9600), 9600.

The biggest problem with that YouTube is that it is not narrated, music does not tell you what the guy is doing.

Tom...

theflyingoreo · June 18, 2017, 1:06am

The Serial Monitor is set at "No line ending" and "9600 baud"

Power_Broker · June 18, 2017, 1:22am

Can you post a picture of your setup and the exact code you are using?

bluejets · June 18, 2017, 1:57am

Julian Ilett has a lot of good video on youtube.

theflyingoreo · June 18, 2017, 2:20am

Power_Broker:
Can you post a picture of your setup and the exact code you are using?

Code:

int ledblue=13;
int tx=1;
int rx=0;
char inSerial[15];

void setup(){
	Serial.begin(9600);
	pinMode(ledblue,OUTPUT);
	pinMode(tx,OUTPUT);
	pinMode(rx,INPUT);
	allpinslow();
}

void loop(){
	int i=0;
	int m=0;
	delay(500);
	if(Serial.available() > 0){
		while(Serial.available() > 0){
			inSerial[i]=Serial.read();
			i++;
		}
		inSerial[i]='\0';
		Check_Protocol(inSerial);
	}
	
}

void allpinslow()
{
  digitalWrite(ledblue, HIGH);
  digitalWrite(ledblue, LOW);
}

void Check_Protocol(char inStr[]){
	int i=0;
	int m=0;
	Serial.println(inStr);
	if(!strcmp(inStr,"2off")){ //Led Off
		allpinslow();
		digitalWrite(ledblue, LOW);
		Serial.println("Blue Off");
		for(m=0;m<11;m++){
			inStr[m]=0;
			}
		i=0;
	}
	if(!strcmp(inStr,"2on")){ //Led on
		allpinslow();
		digitalWrite(ledblue, HIGH);
		Serial.println("Blue on");
		for(m=0;m<11;m++){
			inStr[m]=0;
			}
		i=0;
	}
	else{
		for(m=0;m<11;m++){
			inStr[m]=0;
		}
	i=0;
	}
}

Setup:

[Album] imgur.com

The HC 06 RX is connected the Arduino TX, the HC 06 TX is connected to the RX pin, the VCC pin is connected to the 5 V pin and the HC 06 GND pin is connected to the Arduino GND pin

Wawa · June 18, 2017, 2:31am

theflyingoreo:
The HC 06 RX is connected the Arduino TX, the HC 06 TX is connected to the RX pin, the VCC pin is connected to the 5 V pin and the HC 06 GND pin is connected to the Arduino GND pin

The BT module is a 3.3volt device. RX most be protected from Arduino's 5volt signals.
The youtube video you posted shown a voltage divider on the RX pin for that reason.

The TX/RX pins of the Arduino are also used for serial comms with the USB chip.
Better to use SoftwareSerial (in the examples of the IDE) on different pins for the BT device.

If you use the normal TX/RX pins, dont "pinMode" them.
Leo..

Power_Broker · June 18, 2017, 2:35am

theflyingoreo:
Code:
int ledblue=13;

int tx=1;
int rx=0;
char inSerial[15];

void setup(){
Serial.begin(9600);
pinMode(ledblue,OUTPUT);
pinMode(tx,OUTPUT);
pinMode(rx,INPUT);
allpinslow();
}

void loop(){
int i=0;
int m=0;
delay(500);
if(Serial.available() > 0){
while(Serial.available() > 0){
inSerial[i]=Serial.read();
i++;
}
inSerial[i]='\0';
Check_Protocol(inSerial);
}

}

void allpinslow()
{
digitalWrite(ledblue, HIGH);
digitalWrite(ledblue, LOW);
}

void Check_Protocol(char inStr[]){
int i=0;
int m=0;
Serial.println(inStr);
if(!strcmp(inStr,"2off")){ //Led Off
allpinslow();
digitalWrite(ledblue, LOW);
Serial.println("Blue Off");
for(m=0;m<11;m++){
inStr[m]=0;
}
i=0;
}
if(!strcmp(inStr,"2on")){ //Led on
allpinslow();
digitalWrite(ledblue, HIGH);
Serial.println("Blue on");
for(m=0;m<11;m++){
inStr[m]=0;
}
i=0;
}
else{
for(m=0;m<11;m++){
inStr[m]=0;
}
i=0;
}
}




Setup:
http://imgur.com/a/brexs

The HC 06 RX is connected the Arduino TX, the HC 06 TX is connected to the RX pin, the VCC pin is connected to the 5 V pin and the HC 06 GND pin is connected to the Arduino GND pin

NO, NO, NO. I'm sick of asking people for photo's of their setup and they post a Fritzing diagram. THERE IS A DIFFERENCE. Sorry for the rant, but this is getting ridiculous. If a photo is asked, you should post a photo (like, from a camera that shows your ACTUAL project).

LarryD · June 18, 2017, 2:43am

Also, make sure you post a good image.

How long is your ledblue HIGH in this part of the sketch?

digitalWrite(ledblue, HIGH);
digitalWrite(ledblue, LOW);

Use to format your sketch.

.

TomGeorge · June 18, 2017, 3:09am

Hi,
Forget the fritzy diagram.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

A picture of a hand drawn circuit will be more informative, label ALL components and pinouts used please.
We need to see your BT unit, front and back, as some modules come with 5V inputs and on board regulators.

Thanks.. Tom..

theflyingoreo · June 18, 2017, 3:43am

Wawa:
The BT module is a 3.3volt device. RX most be protected from Arduino's 5volt signals.
The youtube video you posted shown a voltage divider on the RX pin for that reason.

The TX/RX pins of the Arduino are also used for serial comms with the USB chip.
Better to use SoftwareSerial (in the examples of the IDE) on different pins for the BT device.

If you use the normal TX/RX pins, dont "pinMode" them.
Leo..

I tried setting up the circuit with the voltage dividers, but instead of 2.7k and 4.4k ohm resistors, I replaced them both with 1k resistors (the only other resistors I have are 100, 10k, 470k and 10 million) and the exact same issue came up (reverse question marks)

Circuit:

Crappy drawing:

HC 06 Front and Back:

TomGeorge · June 18, 2017, 4:27am

Hi

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

If you read it you will find how to post images as attachments or into posts.

Where is the current limit resistor for the LED?
Off site images may not load on some platforms, iphones, ipads etc..

Tom...

Power_Broker · June 18, 2017, 4:53am

theflyingoreo:
I tried setting up the circuit with the voltage dividers, but instead of 2.7k and 4.4k ohm resistors, I replaced them both with 1k resistors (the only other resistors I have are 100, 10k, 470k and 10 million) and the exact same issue came up (reverse question marks)

Circuit:
https://drive.google.com/open?id=0B4wlioqCTINJS2phdGl4RU1adnM

Crappy drawing:
https://drive.google.com/open?id=0B4wlioqCTINJRzlqWFlzSWxaanc

HC 06 Front and Back:
https://drive.google.com/open?id=0B4wlioqCTINJYWU5U3k3UDM0bE0
https://drive.google.com/open?id=0B4wlioqCTINJWUpaVzZKTHhIZjQ

No offense, but those pictures are pretty bad (the first too at least). You should take new ones so that all the connections are easily seen and verified. Then post those pics.

theflyingoreo · June 18, 2017, 6:15am

Well, to be 100% honest, I don't know how you expect it. Considering none of the wire lengths are customizable (they all have headers and cutting them would defeat the purpose), they're inevitably going to be tangled up when I try to snap a picture of them. Also, the fact that they're long wires makes it hard for me to get any kind of good close up shot while still getting everything in the shot. I tried labeling this portion of the circuit but I don't know if you're going to find it any more useful

The Blink sketch works perfectly, so I know that the LED circuit isn't the source of the problem. The premise is the same as a Blink sketch. When I press the On Button, the app sends the string "2on" to the Arduino, which calls digitalWrite(ledblue,HIGH). When the Off button is pressed, the app sends "2off" to the module, which calls digitalWrite(led,LOW). It's something up with the Bluetooth module. For whatever reason, the Arduino isn't getting the correct string when either button is being pressed.

There's no real way for me to get a decent shot of the Bluetooth module. The module is so small and the wires are long enough to the point where if I zoom out so that I could capture everything, you wouldn't be able to see anything properly.

The module is connected like this:
HC 06 -> Arduino

RX -> TX
TX -> RX
5V -> 5V
GND -> GND

theflyingoreo · June 18, 2017, 8:13pm

Update: So when I call Serial.read(), pressing the ON button results in the Arduino getting the integer 253. When I press the OFF button, the Arduino gets the integer 252. I updated my code to work with this, but I specifically coded my app to send the strings "2on" and "2off". How the hell is the Arduino getting an integer from the module?

Godot11 · June 18, 2017, 8:57pm

Power_Broker:
No offense, but those pictures are pretty bad (the first too at least). You should take new ones so that all the connections are easily seen and verified. Then post those pics.

What did you find bad about the first image? It shows everything clearly, except whether OP mixed the LED's + and - pin. I don't want to be a smartass, I just don't understand...

Power_Broker · June 18, 2017, 9:02pm

Maybe my eyes are bad, but the connections on both the breadboard and Arduino were very difficult to verify without assumptions. It just wasn't clear. It has nothing to do with resolution, but more with composition.

theflyingoreo · June 18, 2017, 9:22pm

I modified my app a little bit and added a green LED too.

Green ON sends the integer 1 -> Serial.read() gets 254
Red ON sends the integer 2 -> Serial.read() gets 255
OFF sends the integer 0 -> Serial.read() gets 254

If I do (psuedocode)

if integerRecieved == 254
//turn green on
else if integerRecieved == 255
//turn red on

this works perfectly (aside from the fact that I can't turn them off, since OFF is 254 as well).

I still have no idea why it's doing this. I thought that there might have been some significance to these number (ie. ASCII values), but that doesn't seem to be the case. This project is simple enough that I could leave it like this and call it a "fix". However, I want to work on some more complex projects and I can't have Serial.read() spitting out random integers. Does anyone have an idea?

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Revesed question mark

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