# Pulling readings from i2c chip into Node-Red

**URL:** https://discourse.nodered.org/t/pulling-readings-from-i2c-chip-into-node-red/19210
**Category:** General
**Created:** [16 December 2019 02:01 UTC](https://discourse.nodered.org/t/pulling-readings-from-i2c-chip-into-node-red/19210 "2019-12-16T02:01:48Z")
**Posts on this page:** 1
**Showing post:** 16

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### Author: ![Nodi.Rubrum](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nodi.rubrum/32/107482_2.png) [@Nodi.Rubrum](https://discourse.nodered.org/u/Nodi.Rubrum)
#### Post date: [12 October 2020 15:43 UTC](https://discourse.nodered.org/t/pulling-readings-from-i2c-chip-into-node-red/19210/16 "2020-10-12T15:43:30Z")

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Search the forum, I posted an example flow that lets you get and set pins for a PCF8574 breakout board or IC with a Raspberry Pi. The trick really is to maintain a 'register' the pin states, so as you toggle stuff, you can maintain what the state is for each pin per change. [So, Have A PCF8574, And Want To Use It Via Node Red?](https://discourse.nodered.org/t/so-have-a-pcf8574-and-want-to-use-it-via-node-red/30853)

Although my solution drives the pins for output, using the flow as a base for reading input should be possible. as well, if anyone wants input support.

I use my flow as a foundation for several solutions, driving relays for example, for my garage door, and lights, my sprinkler controller, etc.

But a word of caution, if you are driving DC switching with relays for example, be sure to know the impact of inductive loads/loading. I only drive 5v and 12v solutions that are DC based, so impact of inductive loading is not significant. But higher DC levels can and does have impact on any relays.

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_[View the full topic](https://discourse.nodered.org/t/pulling-readings-from-i2c-chip-into-node-red/19210)._