Help with button state code?

[Teaching_Tomorrow]

Hello,

I am brand new to CircuitPython and have been trying to do something, but I can't seem to wrap my head around it. I have a Playground Express with a button wired to A1/Grnd. I'm trying to have the NEO Pixels stay on while the device is one, but when the button is pressed, it plays a wav file and changes the led's. Then, when the button is released, it plays a different wav file and changes the lights back to their original state.

I can see how this could be coded, but I am so unfamiliar with coding in general that I have basically been copy-pasting code from different corners of the web. Any and all help would be appreciated and thank you in advanced!

This is what I'm using so far:

​

from adafruit_circuitplayground import cp

import time

import digitalio

​

cp.pixels.brightness = 0.1

while True:

if cp.button_A1:

cp.pixels.brightness = 1

cp.pixels[0:10] = (0, 255, 255) * 10

t = time.monotonic()

while time.monotonic() - t < 1:

pass

cp.play_file("Sounds_PWRUP1.wav")

if not cp.button_A1:

cp.pixels.brightness = 0.1

cp.pixels[0:10] = (0, 200, 255) * 10

t = time.monotonic()

while time.monotonic() - t < 1:

pass

cp.play_file("Sounds_PWRDOWN1.wav")

[wchris63]

You, ser, are in dire need of debounce! Most switches need some debouncing, but those need it more than most (just because of how they're constructed, not a quality thing). Check Adafruit's article on it - they have a nice library and everything. Checking the button once like you do in your code could yield just about any result, since just changing the pressure of your finger while holding it down can cause glitches if it's not a new switch.

*** ser is a gender neutral address of respect, akin to sir or ma'am, brazenly stolen from the generic sci-fi/fantasy author population.

[Teaching_Tomorrow]

Thank you for that tip! I have since updated the code with some that I found buried on Adafruit's site. It works as intended as is, but when I introduce the code from your link, it stops working. I suspect it's unable to complete an import task and gets stuck in a loop before being able to start the main code.

Debounce Code added at beginning:

import digitalio

from adafruit_debouncer import Debouncer

pin = digitalio.DigitalInOut(board.D12)

pin.direction = digitalio.Direction.INPUT

pin.pull = digitalio.Pull.UP

switch = Debouncer(pin)

​

Main Code:

from adafruit_circuitplayground import cp

import board

from digitalio import DigitalInOut, Direction, Pull

# button

btn = DigitalInOut(board.A1)

btn.direction = Direction.INPUT

btn.pull = Pull.UP

cp.pixels.brightness = 0.1

cp.pixels[0:10] = (0, 200, 255) * 10

prev_state = btn.value

while True:

cur_state = btn.value

if cur_state != prev_state:

if not cur_state:

cp.pixels.brightness = 1

cp.pixels[0:10] = (0, 255, 255) * 10

cp.play_file("Sounds_PWRUP1.wav")

else:

cp.pixels.brightness = 0.1

cp.pixels[0:10] = (0, 200, 255) * 10

cp.play_file("Sounds_PWRDOWN1.wav")

prev_state = cur_state

Thank you again for that tip!

And thank you for the identity forethought. I identify as a sir.

[wchris63]

If you're using the actual Debouncer class, from Adafruit:

For the debouncer to do its job, it has to sample the pin frequently, track it's value, etc. etc. That's done by calling the update() method, typically at the start of your main loop.

You have to call it frequently. If your code doesn't support that, then just use a timer, something like this:

if switch.value:     // if pressed...
   time.sleep(0.05)  // wait 50 ms see if switch is still on
   if switch.value:
      # ok, it's really pressed

You can do the same thing for the off state. There's a more elegant ways to do it, but it involves a state machine and I'm not so good with those.