# I2C nodes with arduino

**URL:** <https://discourse.nodered.org/t/i2c-nodes-with-arduino/18064>\
**Category:** General\
**Created:** [17 November 2019 18:27 UTC](https://discourse.nodered.org/t/i2c-nodes-with-arduino/18064 "2019-11-17T18:27:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![caspera](https://avatars.discourse-cdn.com/v4/letter/c/5fc32e/32.png) [@caspera](https://discourse.nodered.org/u/caspera)\
**Post date:** [17 November 2019 18:27 UTC](https://discourse.nodered.org/t/i2c-nodes-with-arduino/18064/1 "2019-11-17T18:27:55Z")

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Hello everyone,  
I am a last year student in ICT and i need to make a big project together with a friend of me so we wanted to try to make a smarthome without a premade OS system(It's scaled and only with 5V electronics). So i downloaded Raspbian on the raspberry pi and now i am using Node-Red and Blynk (for the webserver and app) but my teacher wanted us to use I2C instead of just using every gpio pin.  
Now i want to use a arduino pro mini with my raspberry pi and node-red but i don't know how i can call different programs on the arduino with switch cases. I use the i2c node but don't understand how to node works i got it to work to put all the pins of the arduino on but i can't make different cases in the arduino to control different leds.

Can someone help please (I am dutch so my English isn't the best, sorry for that)

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**Author:** ![craigcurtin](https://avatars.discourse-cdn.com/v4/letter/c/94ad74/32.png) [@craigcurtin](https://discourse.nodered.org/u/craigcurtin)\
**Post date:** [18 November 2019 04:02 UTC](https://discourse.nodered.org/t/i2c-nodes-with-arduino/18064/2 "2019-11-18T04:02:40Z")

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Have a look at Peter Scargills blog - he makes extensive use of Arduino Minis/Nanos as slaves to ESP8266 devices and makes his source code readily available - this should give youa good starting point

Craig