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NodeMCU debounce based on timer with GPIO pullup
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-- inspired by https://github.com/hackhitchin/esp8266-co-uk/blob/master/tutorials/introduction-to-gpio-api.md | |
-- and http://www.esp8266.com/viewtopic.php?f=24&t=4833&start=5#p29127 | |
local pin = 4 --> GPIO2 | |
function debounce (func) | |
local last = 0 | |
local delay = 50000 -- 50ms * 1000 as tmr.now() has μs resolution | |
return function (...) | |
local now = tmr.now() | |
local delta = now - last | |
if delta < 0 then delta = delta + 2147483647 end; -- proposed because of delta rolling over, https://github.com/hackhitchin/esp8266-co-uk/issues/2 | |
if delta < delay then return end; | |
last = now | |
return func(...) | |
end | |
end | |
function onChange () | |
print('The pin value has changed to '..gpio.read(pin)) | |
end | |
gpio.mode(pin, gpio.INT, gpio.PULLUP) -- see https://github.com/hackhitchin/esp8266-co-uk/pull/1 | |
gpio.trig(pin, 'both', debounce(onChange)) |
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@Bop4yN you're missing that
debounce
returns a function (line 9-17). So, every time the GPIO triggers it doesn't rundebounce
but the function it returned when it was once (i.e. initially) called. That inner function has access tolast
and keeps changing it.-> https://en.wikipedia.org/wiki/Closure_(computer_programming)