GPIO button to complete input prompt

Question

I would like to prompt the user for input, then with the push of a GPIO button, submit the input value. This is tricky since the GPIO button polling is typically done in a loop.

I was thinking that somehow this could accomplished by using two threads with a join, but I'm not really sure how to make it a tight integration.

Any ideas?

Answer 1

Have you seen this tutorial:

def my_callback(channel):  
    print "Rising edge detected on port 24 - even though, in the main thread,"  
    print "we are still waiting for a falling edge - how cool?\n"  

print "Make sure you have a button connected so that when pressed"  
print "it will connect GPIO port 23 (pin 16) to GND (pin 6)\n"  
print "You will also need a second button connected so that when pressed"  
print "it will connect GPIO port 24 (pin 18) to 3V3 (pin 1)"  
raw_input("Press Enter when ready\n>")  

# The GPIO.add_event_detect() line below set things up so that  
# when a rising edge is detected on port 24, regardless of whatever   
# else is happening in the program, the function "my_callback" will be run  
# It will happen even while the program is waiting for  
# a falling edge on the other button.  
GPIO.add_event_detect(24, GPIO.RISING, callback=my_callback)  

try:  
    print "Waiting for falling edge on port 23"  
    GPIO.wait_for_edge(23, GPIO.FALLING)  
    print "Falling edge detected. Here endeth the second lesson."  

except KeyboardInterrupt:  
    GPIO.cleanup()       # clean up GPIO on CTRL+C exit  
GPIO.cleanup()           # clean up GPIO on normal exit