# Modify MQTT payload according to 24 hr timer

**URL:** <https://discourse.nodered.org/t/modify-mqtt-payload-according-to-24-hr-timer/12836>\
**Category:** General\
**Created:** [2 July 2019 19:07 UTC](https://discourse.nodered.org/t/modify-mqtt-payload-according-to-24-hr-timer/12836 "2019-07-02T19:07:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![m\_elias](https://avatars.discourse-cdn.com/v4/letter/m/94ad74/32.png) [@m\_elias](https://discourse.nodered.org/u/m_elias)\
**Post date:** [2 July 2019 19:07 UTC](https://discourse.nodered.org/t/modify-mqtt-payload-according-to-24-hr-timer/12836/1 "2019-07-02T19:07:47Z")

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Hi,

I have an Arduino thermostat controlled via MQTT. I'd like to change my temperature set point higher in the morning and lower in the evening by a set amount. I was thinking of using BigTimer and a function node but I'm not sure how to monitor my set point topic & store it until the BigTimer triggers. Do I use 2 function nodes? One to save my set point changes to the flow context and another to read the flow context and build a payload when BigTimer fires?

Is a better/simpler way to do it?

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [2 July 2019 20:33 UTC](https://discourse.nodered.org/t/modify-mqtt-payload-according-to-24-hr-timer/12836/2 "2019-07-02T20:33:01Z")

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Have a look at node-red-contrib-ramp-thermostat which allows a temperature profile to be configured, which you can then send to your Arduino. The node also includes a thermostat but you can just ignore that feature and use the profiling.

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<div class="post-metadata">

**Author:** ![m\_elias](https://avatars.discourse-cdn.com/v4/letter/m/94ad74/32.png) [@m\_elias](https://discourse.nodered.org/u/m_elias)\
**Post date:** [3 July 2019 15:34 UTC](https://discourse.nodered.org/t/modify-mqtt-payload-according-to-24-hr-timer/12836/3 "2019-07-03T15:34:39Z")

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Thanks, for now I've figured it out but if I need a more complex schedule then I'll take another look at ramp-thermostat.

 ![thermo](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/a/aaad126e8b16043b135da64cf404c8b7e6762393.jpeg)