# Conflicting sensors usb

**URL:** <https://discourse.nodered.org/t/conflicting-sensors-usb/25297>\
**Category:** General\
**Created:** [22 April 2020 11:39 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297 "2020-04-22T11:39:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Niki](https://avatars.discourse-cdn.com/v4/letter/n/c57346/32.png) [@Niki](https://discourse.nodered.org/u/Niki)\
**Post date:** [22 April 2020 11:39 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297/1 "2020-04-22T11:39:41Z")

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Hi all I’m still new with raspberry pi and node red so go easy

My project consists of two sensors which are identical (SDS011) and are connected to the pi via usb, to gather results which are displayed on a chart and gauge I’m using the following flow

[https://flows.nodered.org/flow/7be04043044e08e1d3ac02da28223fe3](https://flows.nodered.org/flow/7be04043044e08e1d3ac02da28223fe3)

When one of the sensors is connect all works fine, the problem is when I copy the flow for the other sensor I get the problem, instead of just changing the serial port from sensor 1 to tty usb0 and sensor 2 usb1 node red will only read from one sensor.

To overcome this I tried to rename the USB ports and permanently connect the sensors to specific USB ports when doing this I was able to find atty idproduct and idvendor but both values were the same and as no serial number I used the kernels number of the port.

Some progress made is both sensors are now reading the problem now is it looks as though both sensors are trying to feed data into the same graph and gauges

So I’m trying to get all 4 gauges and the two graphs to run

Any help much appreciated please remember don’t get too technical as my knowledge on this is basic 🤣

Cheers

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**Author:** ![kevinksdroid](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@kevinksdroid](https://discourse.nodered.org/u/kevinksdroid)\
**Post date:** [22 April 2020 12:06 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297/2 "2020-04-22T12:06:29Z")

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Can you share the flow?

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**Author:** ![Niki](https://avatars.discourse-cdn.com/v4/letter/n/c57346/32.png) [@Niki](https://discourse.nodered.org/u/Niki)\
**Post date:** [22 April 2020 12:32 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297/3 "2020-04-22T12:32:39Z")

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Hi Kevin

Link to flow

[https://flows.nodered.org/flow/7be04043044e08e1d3ac02da28223fe3](https://flows.nodered.org/flow/7be04043044e08e1d3ac02da28223fe3)

All I have done is delete the dht2 sensor part and comply past so I have to flows one for each sensor

Cheers

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**Author:** ![Niki](https://avatars.discourse-cdn.com/v4/letter/n/c57346/32.png) [@Niki](https://discourse.nodered.org/u/Niki)\
**Post date:** [22 April 2020 14:30 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297/4 "2020-04-22T14:30:42Z")

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Sorry that was copy and paste so I have two flows for each sensor

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [21 June 2020 14:30 UTC](https://discourse.nodered.org/t/conflicting-sensors-usb/25297/5 "2020-06-21T14:30:45Z")

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