# Using a digital input to ramp up

**URL:** <https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585>\
**Category:** General\
**Created:** [17 July 2024 21:36 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585 "2024-07-17T21:36:15Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Tontonsams](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/tontonsams/32/92877_2.png) [@Tontonsams](https://discourse.nodered.org/u/Tontonsams)\
**Post date:** [17 July 2024 21:36 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/1 "2024-07-17T21:36:15Z")

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Hey I have a question about a ramp up i'm trying to create.

case : I have a speedcontroller -10 to +10V regulated. i want to use a potmeter to set the nominal speed. (value X) but before reaching that value, I would like a ramp up and ramp down set with a time value (time to nominal speed).

I found a "ease" node, that contains all the fancy ramps i need, but having a digital pin start a ramp up, nominal -\> until the Digital Pin changes to false and then ramp down.

curious if this is possible!

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**Author:** ![gerry](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/gerry/32/21604_2.png) [@gerry](https://discourse.nodered.org/u/gerry)\
**Post date:** [18 July 2024 02:17 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/2 "2024-07-18T02:17:57Z")

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There are digital potentiometers that may help. Without offering anything specific if you use one of those you could hit it with a PWM or a climbing and descending digital number to vary resistance depending on which digipot you use. I can see a fairly simple function node there but there may be better nodes available.

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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:** [18 July 2024 06:13 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/3 "2024-07-18T06:13:35Z")

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> [@Tontonsams](#):
>
> I would like a ramp up and ramp down set with a time value

Do you want a set time or a fixed ramp rate?  
A fixed ramp rate to a value is easier.

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**Author:** ![Tontonsams](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/tontonsams/32/92877_2.png) [@Tontonsams](https://discourse.nodered.org/u/Tontonsams)\
**Post date:** [18 July 2024 08:50 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/4 "2024-07-18T08:50:11Z")

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it's over time.

but i found the functionality of the ease node, this works well, only that i need to be able to set the parameter without it starting 🙂  
now when i throw a JSON at it to set the values, it start directly.  
am i correct assuming I need to start it always with a json?

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<div class="post-metadata">

**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:** [18 July 2024 13:43 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/5 "2024-07-18T13:43:21Z")

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> [@Tontonsams](#):
>
> it's over time.

That is a pity as I have a flow that you can send a value to and it will go from the current value to the new value at a defined rate, then you can send it another value and it will ramp to that one.

> [@Tontonsams](#):
>
> am i correct assuming I need to start it always with a json?

I don't know anything about that node.

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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:** [16 October 2024 13:43 UTC](https://discourse.nodered.org/t/using-a-digital-input-to-ramp-up/89585/6 "2024-10-16T13:43:53Z")

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