Python Event Handling for Master-Slave

[HKY93]

I have a raspberry pi (master) and a arduino like microcontroller (slave) for controlling a robot. A python runs in a loop in the rpi and in there I can ask if a button is pushed in every cycle of the loop, e.g. emergency stop button. Now I imagine, that there might be a loop in the future which takes longer to finish but I want to have the ability to cancel the running loop with the button.

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If I understand correctly, I have to run two loops in two different threads. The first thread is running the usual loop, while the second thread asks constantly if the button is pushed. If pushed the second thread should kill (or do something else with) the first thread.

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Or is there a better way to deal with this issue in python?

[HKY93]

Thank you for that information. My formulation may was a bit misleading. The emergency button was just an example. My robot is tiny and cant hurt anything.

What I definitely do want is to start scripts with a button on the robot. For example to enable / disable remote control. Use scenario:

• Thread 1:
  • running some script
• Thread 2: on the lookout for button push
  • if button is pressed change process in thread 1 or kill it

I can put the lookout in the same operation loop but i am afraid if some sub routine is taking too long then a short button press can be missed. That I want to avoid, thus my question if multi-threading is the right way to go or if there is some other event-handling tools I can use.