# Node that does FIFO function maybe

**URL:** <https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885>\
**Category:** General\
**Created:** [15 November 2023 14:18 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885 "2023-11-15T14:18:49Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**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:** [15 November 2023 14:18 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/1 "2023-11-15T14:18:49Z")

</div>

I have a situation I need some help with. I am building a child's game (not my idea) where they are in a large room. There are four corners with a light in each corner.

 ![step1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/2/6/2635028b4cc4324e210417758b39d65b999193bb.jpeg)

The idea is that as the lights light up the children run to that corner of the room. At any given time there are only two lights on. The one where they are and the one they are running to. The lights start in a random corner and go in a random sequence. That part I can manage. My problem is turning off the lights in the correct sequence.

 ![step2](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/9/19320247ca1789a0be0da73c967a28bf78f49edd.jpeg)

 ![step3](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/6/c/6c50d991b160e1214bef53a3c3bf4591db3dcd33.jpeg)

 ![step4](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/9/0/90f50f29d2417b6f26b24b244925d12eb0f2291d.jpeg)

The lights turn on in any order and must be turned off in the same sequence. This seems like a FIFO problem but I can't wrap my head this.

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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:** [15 November 2023 14:32 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/2 "2023-11-15T14:32:27Z")

</div>

When should it switch off?

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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:** [15 November 2023 14:37 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/3 "2023-11-15T14:37:48Z")

</div>

If you want it to turn off a fixed time after you turn on the next one, then construct the message to turn off the original light at the same time as you turn the next one on, but send it through a delay node with the appropriate delay time configured.

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<div class="post-metadata">

**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:** [15 November 2023 14:57 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/4 "2023-11-15T14:57:24Z")

</div>

The light will probably be on around 15 seconds, but how do I get around the random problem

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<div class="post-metadata">

**Author:** ![smanjunath211](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/smanjunath211/32/95742_2.png) [@smanjunath211](https://discourse.nodered.org/u/smanjunath211)\
**Post date:** [15 November 2023 15:12 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/5 "2023-11-15T15:12:43Z")

</div>

Did I understand the logic correctly ?

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```

![new](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/8/0/80b4af56ced63fc7aed6e03f97f9a03d78f9f85a.gif)

---

<div class="post-metadata">

**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:** [15 November 2023 15:27 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/6 "2023-11-15T15:27:10Z")

</div>

yep you got it exactly right! thanks

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [29 November 2023 15:27 UTC](https://discourse.nodered.org/t/node-that-does-fifo-function-maybe/82885/7 "2023-11-29T15:27:15Z")

</div>

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