device.send() doesn't work in ofApp::setup() - PacketSerial

[vvzen]

Hi,
I'm using this addon for an installation where I'm controlling multiple steppers and servos and it works great if the code where I send the message via serial is inside an event listener function (like mousePressed() or keyPressed() ), but not if I use it inside setup() or update().

To be more precise, this is the code that I'm using to send the osc message via serial (modelled on the OSC-SLIP packet example):

ofxOscMessage osc_message;
osc_message.setAddress("/home");
osc_message.addIntArg(1);

send_osc_bundle(osc_message, cnc_device, 1024);

1. If I only put these 4 lines inside a ofApp::keyPressed(), it works ok. ✅

2. If I instead put them inside ofApp::setup() , after setting up the serial device, it does not work. ❌

3. Finally, if I put them inside ofApp::setup() and also inside ofApp::keyPressed(), even the keyPressed() event doesn't work. ❌

For reference, this is my send_osc_bundle().

//--------------------------------------------------------------
void ofApp::send_osc_bundle(ofxOscMessage &m, ofxIO::SLIPPacketSerialDevice &device, int buffer_size){
    
    // this code comes from ofxOscSender::sendMessage in ofxOscSender.cpp
    // static const int OUTPUT_BUFFER_SIZE = buffer_size;
    char buffer[buffer_size];

    // create the packet stream
    osc::OutboundPacketStream p(buffer, buffer_size);
    
    p << osc::BeginBundleImmediate; // start the bundle
    append_message(m, p);           // add the osc message to the bundle
    p << osc::EndBundle;            // end the bundle
 
    // send to device
    device.send(ofxIO::ByteBuffer(p.Data(), p.Size()));
}

The append_message() is the exact same code of the examples.

Any hint would be great! I've been struggling with this for quite a while.

Thanks!

[vvzen]

As an addendum, it might just be that I need to wait a little bit before sending data?

If I do something like that, it seems to be working good.
(homed starts as false)

void ofApp::update(){

    if ((int) ofGetElapsedTimef() < 6){
        int elapsed_time = (int) ofGetElapsedTimef();
        ofLogNotice() << "elapsed time: " << elapsed_time;

        if (elapsed_time == 5 && !homed){
            ofLogNotice() << "sending home";
       
            ofxOscMessage osc_message;
            osc_message.setAddress("/home");
            osc_message.addIntArg(1);

            send_osc_bundle(osc_message, cnc_device, 1024);

            homed = true;
        }
    }
}

[bakercp]

It's hard to say what's going on without knowing the exact hardware setup / Arduino code. As far as I know you should be able to send serial commands in setup(). Rather than timers etc, I would make the Arduino respond with an ACK like message of some kind before proceeding ... ?

[vvzen]

@bakercp Thanks for answering!
I'm using an Arduino Mega, the code can be found here: https://github.com/vvzen/maca-final/blob/master/arduino/stepper-no-lib-mega/stepper-no-lib-mega.ino
Yep probably in the final build I will do a handshake or acknowledgement sort of thing before starting sending to the arduino.
But for now waiting (even a second) before sending the first message seems to work. ( https://github.com/vvzen/maca-final/blob/master/coherent-lines-dots/src/ofApp.cpp )
Maybe there's a race condition somewhere?

Thanks!