# Get value from MQTT and set a variable

**URL:** <https://community.homey.app/t/get-value-from-mqtt-and-set-a-variable/6090>\
**Category:** Questions & Help\
**Created:** [December 30, 2018, 12:01pm UTC](https://community.homey.app/t/get-value-from-mqtt-and-set-a-variable/6090 "2018-12-30T12:01:31Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![Kalle\_Kronbeck](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kalle_kronbeck/32/13158_2.png) [@Kalle\_Kronbeck](https://community.homey.app/u/Kalle_Kronbeck)\
**Post date:** [June 4, 2019, 1:25pm UTC](https://community.homey.app/t/get-value-from-mqtt-and-set-a-variable/6090/7 "2019-06-04T13:25:17Z")

</div>

> [@dewenni](#):
>
> var MyNum = parseFloat(args[0])

That worked.  
But I dont get my virtual device (temperature) to update.  
Running this flow

 ![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/2X/f/f48bb85ad0f45fc267c4736cae4a9cc38e98f2e2.jpeg)

How do I know if my tag is a STRING or VALUE ?

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