# Command buffer size exceeded ( esp8266 mcu/mqtt + bme280)

**URL:** <https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028>\
**Category:** XOD Programming Questions\
**Created:** [May 28, 2020, 12:29pm UTC](https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028 "2020-05-28T12:29:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![scotthaije](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@scotthaije](https://forum.xod.io/u/scotthaije)\
**Post date:** [May 28, 2020, 12:29pm UTC](https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028/1 "2020-05-28T12:29:30Z")

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Hi all !

when i want to upload a program with the mqtt pub/ sub nodes and the esp8266 mcu to my esp 12E board, it works all fine. I tested it with a combo of node red on my raspberry pi. And it works good ! ( thanks bradzilla for the mqtt nodes )

Butt when i want to send data from my BME 280 sensor to the mqtt publish node, and then upload the sketch. i got the error ‘’ Command maxBuffer size exceeded "

i replaced the bme280 sensor with anolog read/ digital read. and then it works fine !

is the bme280 node really that big ? or did i something wrong ?

 ![buffer size problem](https://canada1.discourse-cdn.com/flex027/uploads/xod/original/2X/3/3d48d3665f6220122020188127ab10875bafb76f.jpeg)

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**Author:** ![gabbapeople](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/gabbapeople/32/1517_2.png) [@gabbapeople](https://forum.xod.io/u/gabbapeople)\
**Post date:** [May 28, 2020, 1:29pm UTC](https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028/2 "2020-05-28T13:29:53Z")

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@scotthaije, Hi!

Who made this node? `bmx280`? Since it is created by a community member, you need to ask its creator. It seems that this node has some C++ memory usage/allocation/optimization mistakes.

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**Author:** ![scotthaije](https://avatars.discourse-cdn.com/v4/letter/s/ba9def/32.png) [@scotthaije](https://forum.xod.io/u/scotthaije)\
**Post date:** [May 28, 2020, 1:46pm UTC](https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028/3 "2020-05-28T13:46:35Z")

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@gabbapeople . Thanks for the fast reply !

i believe that @dinosalvioni made the bmx280 library, i realy hope that he can help/ provide some information.

the bmx280 without the mqtt nodes works like a charm btw 🙂

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**Author:** ![system](https://canada1.discourse-cdn.com/flex027/uploads/xod/original/1X/eb7348baa04192c2ef932d1db54d44f09f8a7888.png) [@system](https://forum.xod.io/u/system)\
**Post date:** [June 27, 2020, 1:46pm UTC](https://forum.xod.io/t/command-buffer-size-exceeded-esp8266-mcu-mqtt-bme280/4028/4 "2020-06-27T13:46:39Z")

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