# Arduino & MQTT, which library are you using?

**URL:** <https://forum.inductiveautomation.com/t/arduino-mqtt-which-library-are-you-using/104649>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [April 3, 2025, 1:59pm UTC](https://forum.inductiveautomation.com/t/arduino-mqtt-which-library-are-you-using/104649 "2025-04-03T13:59:22Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![drewdin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/drewdin/32/3363_2.png) [@drewdin](https://forum.inductiveautomation.com/u/drewdin)\
**Post date:** [April 3, 2025, 1:59pm UTC](https://forum.inductiveautomation.com/t/arduino-mqtt-which-library-are-you-using/104649/1 "2025-04-03T13:59:22Z")

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Just checking in to see who's using their Arduino and MQTT to ignition. I had an Arduino UNO lying around with an Ethernet board so figured I would get it talking with MQTT.

I am trying to use the ArduinoMqttClient library, it gets to ignition and then I get connection refused. I am using username/password and the chariot broker.

Just curious if you are using an Arduino, what library did you use and how is it working for you?