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I believe your issue is that you're creating Publisher inside the callback function that handles your keypress. That is not going to work: setting up Publishers and getting Subscribers to notice them and subscribe to them is going to take some time.

You'll want to treat Publishers and Subscribers as persistent objects, that you create once, somewhere in the initialisation phase of your program, and then use inside your callback.

Second: never include any sort of blocking while inside a callback: callbacks like this are supposed to quickly process an event and then return. Including a loop of any kind will make that impossible, and may even block your entire program. With Python this is sometimes hard to detect / notice, as it may spawn N threads to process these things. In your case, that may lead to N instances of Publisher, all publishing Empty msgs at 10 Hz to the bebop/takeoff, even after you've let go of the key.

My advise would be to structure your code similar to how teleop_twist_key.py is setup already, but making sure that the Empty msg gets published by your Publisher when the key you'd like to use is pressed. You'll have to make sure that the code doesn't get to this section if your keys are pressed, because otherwise it will also publish a Twist msg, which is probably not what you want (or it could be, if you'd like to exploit the "publish all-zeros Twist if I haven't pressed any key" behaviour).

I believe your issue is that you're creating Publisher inside the callback function that handles your keypress. That is not going to work: setting up Publishers and getting Subscribers to notice them and subscribe to them is going to take some time.

You'll want to treat Publishers and Subscribers as persistent objects, that you create once, somewhere in the initialisation phase of your program, and then use inside your callback.

Second: never include any sort of blocking while inside a callback: callbacks like this are supposed to quickly process an event and then return. Including a loop of any kind will make that impossible, and may even block your entire program. With Python this is sometimes hard to detect / notice, as it may spawn N threads to process these things. In your case, that may lead to N instances of Publisher, all publishing Empty msgs at 10 Hz to the bebop/takeoff, even after you've let go of the key.

My advise would be to structure your code similar to how teleop_twist_key.py is setup already, but making sure that the Empty msg gets published by your Publisher when the key you'd like to use is pressed. You'll have to make sure that the code doesn't get to this section if your keys are pressed, because otherwise it will also publish a Twist msg, which is probably not what you want (or it could be, if you'd like to exploit the "publish all-zeros Twist if I haven't pressed any key" behaviour).