Arduino: port.write() freezes processing when bluetooth connection is unavailable

JekObliv

Arduino: port.write() freezes processing when bluetooth connection is unavailable

in Integration and Hardware • 1 month ago

Hello. I'm using this code to check the connection between an arduino board and processing (PC). try { port.write(222); } catch (Exception offline) { offScreen = 1; } When the arduino is been connected via usb cable to the pc usb port everything work great.If the usb cable has been unpluged the offscreen value became '1'. The problem is, that if I use a bluetooth module for a serial connection instead of usb cable, when the program tries to write to the port the "222", the program crashes. The catch function does not work. Any suggestions? Thanks

Replies(10)

PhiLho

Re: Try... Catch

1 month ago

Processing rarely throws exceptions, preferring displaying them in the console, so try / catch around its functions is useless in most cases.

JekObliv

Re: Try... Catch

1 month ago

Thanks for your reply! But why this works only with usb cable? Is there a way if the connection with bluetooth module has been lost, the app won't crash and display some kind of message?

PhiLho

Re: Try... Catch

1 month ago

I have no idea, as I don't have these devices...
But to get the discussion going, I suggest you paste here the "kind of message" you get, and tell how the sketch is crashing.

dimkir

Re: Try... Catch

1 month ago

First of all you have to print the stack trace to figure out which exactly exception has happened and where.

To do this you have to add printStackTrace() call to your code. Like this:

if (waitD > 1500) {
try {
port.write(222);
}
catch (Exception offline) {
offline.printStackTrace();
offScreen = 1;
}

now, when you run your code, you will get on your PDE console some big (usually red) error message and stack trace, you have to paste it here. This message would allow to look "under the hood" of port.write() and help to guess what's wrong.

JekObliv

Re: Try... Catch

1 month ago

Thanks dimkir for the suggestion.

I tried to add offline.printStackTrace(); command t o my code but still, when the processing tries to write data to the bluetooth module (that it has been disconnected), the program crashes and it needs force quit.

The offline.printStackTrace(); does not return (on console) any result, because the program seems to crash 3 lines above.

I experience this problem only by using the bluetooth module. In usb/cable connection all works like a charm.

Are any settings to be changed on the bluetooth module or a library on processing in order to be able to check the status of the bluetooth connection?

m.peres

Re: Try... Catch

1 month ago

You could try checking if the serial port is present with Serial.list(). Also, take a look at http://stackoverflow.com/questions/16962442/bluetooth-com-port-not-detected-by-the-processing-application-mac-osx

dimkir

Re: Try... Catch

1 month ago

I looks like you're using Arduino version of "processing" ide??? They had a long-standing bug with bluetooth implementation (which would usually freeze the IDE or smth). You may try using this IDE: Arduino ERW

https://code.google.com/p/arduino-erw/

Honestly, I just played around with arduino a little and don't remember many details, except that there was as well some problem with bluetooth. So I am not promising that my suggestion will work ;) Or if it's relevant to your specific problem at all :D

JekObliv

Re: Try... Catch

1 month ago

I figure it out how I can make this work! Arduino send a request pulse to processing via bluetooth, and then processing replies instantly with a response pulse. So if the connection has been lost, processing will not sent any data to arduino because this is no request pulse to tigger the process! Everything works great! P.s: dimkir, I will try your suggestion anyway! Thanks guys for your time and your help! :)

dimkir

Re: Try... Catch

1 month ago

Great that you fixed it!

I found some links to the old problem i had with Arduino IDE and steps how to fix it.

I will just dump here couple of links, in case someone arrives to this thread with similar problem.

Basically problem is described as here:

https://code.google.com/p/arduino/issues/detail?id=143

but solution was to use ERW IDE

http://forum.arduino.cc/index.php?topic=118440.0

so just in case you stumble upon similar behaviour, you know how to sort it! :)

ps. also as we realize now, your request has not much to do with try{}catch{} , but rather with arduino and bluetooth, so maybe it's better to rename the thread into something like "Arduino port.write() crash freeze when using bluetooth" or smth. may help people who search the forum in future.

JekObliv

Re: Arduino: port.write() freezes processing when bluetooth connection is unavailable

1 month ago

Done! Thanks again for your help:)

Top Reply