# Raspberry Pi Serial

**URL:** <https://discourse.nodered.org/t/raspberry-pi-serial/4988>\
**Category:** General\
**Created:** [17 November 2018 22:15 UTC](https://discourse.nodered.org/t/raspberry-pi-serial/4988 "2018-11-17T22:15:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![j-dizzle](https://avatars.discourse-cdn.com/v4/letter/j/ebca7d/32.png) [@j-dizzle](https://discourse.nodered.org/u/j-dizzle)\
**Post date:** [17 November 2018 22:15 UTC](https://discourse.nodered.org/t/raspberry-pi-serial/4988/1 "2018-11-17T22:15:28Z")

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Hi, I am very new to Node-Red but I have red all the documentation I can find and I am still confused. I am trying to use an arduino (the adafruit trellis m4 express) hooked up over a serial connection to my pi running node-red. I would like to read the input of the serial monitor on my pi and detect what button is pushed, however my problem is I don't understand the trigger for node red.  
tl;dl: I don't understand how the serial nodes work in node-red and I couln't find any documentation to help  
Thanks

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [17 November 2018 23:05 UTC](https://discourse.nodered.org/t/raspberry-pi-serial/4988/2 "2018-11-17T23:05:40Z")

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The only tricky part is knowing what "device" your serial connection attaches itself to. There are various ways to discover this if you need to - a quick Internet search will lead the way.

Assuming you can find that, all you do is add the serial-in node then double click to get to the edit properties. and add a new serial port:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/a/a65e76cac08a0edbca168d7797ee0292f3e87d87.png)

Configure that to point to the serial port you are using. This is quite a common setting:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/8/884417cc51af5301a5ab9fbfe7704aebfaa95862.png)

I have 2 serial inputs on my live Pi based home automation system:

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/4/480b45c19b4d2c14f0bf5b105f88a8c6a7ad3531.png)

The RFX node also uses a serial connection.