# Rising front raspberry

**URL:** <https://discourse.nodered.org/t/rising-front-raspberry/28393>\
**Category:** Dashboard\
**Created:** [16 June 2020 08:44 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393 "2020-06-16T08:44:54Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [16 June 2020 08:44 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/1 "2020-06-16T08:44:55Z")

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hi everyone, I have to detect the rising edge of an input raspberry pin to send an email.  
I'll explain my problem.  
when the raspberry button is closed, he sends me the email two or three times.  
I wanted to send only one.  
so to do this I would have to detect the rising edge of my raspberry.  
I also tried to increase the Debounce time, but nothing.  
it happens that I send an email when the button is pressed and another when the button is released.  
help I don't know how.

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**Author:** ![stefan24](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/stefan24/32/23075_2.png) [@stefan24](https://discourse.nodered.org/u/stefan24)\
**Post date:** [16 June 2020 08:54 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/2 "2020-06-16T08:54:09Z")

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How often do you press the button? You could limit the button presses to 1 msg / second via the delay node.

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [16 June 2020 09:19 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/3 "2020-06-16T09:19:41Z")

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It is an alarm that when the maintenance hour has arrived, the contact is always pressed.  
but when I reopen the contact it triggers another event which then sends another email

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**Author:** ![stefan24](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/stefan24/32/23075_2.png) [@stefan24](https://discourse.nodered.org/u/stefan24)\
**Post date:** [16 June 2020 09:33 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/4 "2020-06-16T09:33:46Z")

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I think I got it, but to be sure, who or what presses the contact, how is the button connected to the Raspi?  
Who opens the contact afterwards and WHEN?

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [16 June 2020 09:53 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/5 "2020-06-16T09:53:17Z")

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If what you want is only to detect a change from 0 to 1 but not a change from 1 to 0 then feed the GPIO node into a Switch node (not a ui-switch) configured like this, then it will pass on a 0 to 1 change bit ignore a 1 to 0 change.

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/4/7/47bf6d38e40f66a825b9c2ba753032eacfa4b33c.png)

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [16 June 2020 10:01 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/6 "2020-06-16T10:01:35Z")

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I'm controlling it with the pressure of the finger.  
but is there a way to peck the rising edge of the button and not the falling one?  
because the raspberry node triggers two events one when I press the button and the other when I release the button.

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**Author:** ![cigno](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/cigno/32/91812_2.png) [@cigno](https://discourse.nodered.org/u/cigno)\
**Post date:** [16 June 2020 10:05 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/7 "2020-06-16T10:05:49Z")

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thanks colin i solved thanks a lot

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [30 June 2020 10:05 UTC](https://discourse.nodered.org/t/rising-front-raspberry/28393/8 "2020-06-30T10:05:55Z")

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