# General

**URL:** https://discourse.nodered.org/c/general/7.md?page=155

[Latest](https://discourse.nodered.org/latest.md) · [Categories](https://discourse.nodered.org/categories.md) · [Tags](https://discourse.nodered.org/tags.md)

**Page:** 156

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## [Node-RED MCU - unhandled exceptions causing endless loop?](https://discourse.nodered.org/t/node-red-mcu-unhandled-exceptions-causing-endless-loop/83044)

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**Author:** [@shrickus](https://discourse.nodered.org/u/shrickus)\
**Replies:** 7\
**Last updated:** [28 November 2023 19:23 UTC](https://discourse.nodered.org/t/node-red-mcu-unhandled-exceptions-causing-endless-loop/83044 "2023-11-28T19:23:10Z")

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Not sure if this is an issue inside moddable or node-red-mcu, but anytime the generated node-red flows running on my ESP-32 hit an error, the whole unit restarts... and fails again. In my particular flow, I just added a…

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## [Device list in zigbee2mqtt bridge lässt sich nicht mehr ändern](https://discourse.nodered.org/t/device-list-in-zigbee2mqtt-bridge-lasst-sich-nicht-mehr-andern/83059)

<div class="topic-metadata">

**Author:** [@mweissen](https://discourse.nodered.org/u/mweissen)\
**Replies:** 7\
**Last updated:** [28 November 2023 17:49 UTC](https://discourse.nodered.org/t/device-list-in-zigbee2mqtt-bridge-lasst-sich-nicht-mehr-andern/83059 "2023-11-28T17:49:44Z")

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NodeRed version 3.0.2 Seit kurzem ist es nicht mehr möglich, in der Zigbee2mqtt bridge die Liste der Devices zu verändern: "Friendly name"s können nicht geändert werden, neue Devices erscheinen nach dem pairing nicht au…

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## [How to get opcua curves from array of extension object?](https://discourse.nodered.org/t/how-to-get-opcua-curves-from-array-of-extension-object/83253)

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**Author:** [@Elo](https://discourse.nodered.org/u/Elo)\
**Replies:** 0\
**Last updated:** [28 November 2023 15:30 UTC](https://discourse.nodered.org/t/how-to-get-opcua-curves-from-array-of-extension-object/83253 "2023-11-28T15:30:15Z")

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If I access the opcua server in the UaExpert software I can see CycleDoneEventType message with all data points in the Event View tab. In the node-red, the extension object array is empty.

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## [Howto read rpi gpio state after reboot](https://discourse.nodered.org/t/howto-read-rpi-gpio-state-after-reboot/83218)

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**Author:** [@Kliurka](https://discourse.nodered.org/u/Kliurka)\
**Replies:** 10\
**Last updated:** [28 November 2023 14:08 UTC](https://discourse.nodered.org/t/howto-read-rpi-gpio-state-after-reboot/83218 "2023-11-28T14:08:52Z")

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howto read rpi gpio state after rpi reboot, or howto initiate force read gpio

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## [Strange visual goings on in editor](https://discourse.nodered.org/t/strange-visual-goings-on-in-editor/83215)

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**Author:** [@cymplecy](https://discourse.nodered.org/u/cymplecy)\
**Replies:** 6\
**Last updated:** [28 November 2023 12:08 UTC](https://discourse.nodered.org/t/strange-visual-goings-on-in-editor/83215 "2023-11-28T12:08:11Z")

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I've noticed a bit of a glitch Note how the wire looping back underneath the Blocky node loops much lower down than the green unexpected debug node one But if I copy it to another tab - effect disappears Just put…

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## [Node: "read file" debug: Error: EACCES: permission denied, open 'x.json'"](https://discourse.nodered.org/t/node-read-file-debug-error-eacces-permission-denied-open-x-json/83225)

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**Author:** [@Bitmage77](https://discourse.nodered.org/u/Bitmage77)\
**Replies:** 13\
**Last updated:** [28 November 2023 11:34 UTC](https://discourse.nodered.org/t/node-read-file-debug-error-eacces-permission-denied-open-x-json/83225 "2023-11-28T11:34:20Z")

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Hello, i am very new and I hope someone can help me. I am using a Linux system with IO-Broker and Node-Red. Everything is running on the newest version. I created a ".json" on my linux system under "/home/user/x.json". …

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## [Javascript chart code](https://discourse.nodered.org/t/javascript-chart-code/83247)

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**Author:** [@girigowda](https://discourse.nodered.org/u/girigowda)\
**Replies:** 1\
**Last updated:** [28 November 2023 11:26 UTC](https://discourse.nodered.org/t/javascript-chart-code/83247 "2023-11-28T11:26:43Z")

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in node red how to create a chart javascript code

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## [Time format conversion](https://discourse.nodered.org/t/time-format-conversion/83184)

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**Author:** [@juntiedt](https://discourse.nodered.org/u/juntiedt)\
**Replies:** 7\
**Last updated:** [28 November 2023 11:19 UTC](https://discourse.nodered.org/t/time-format-conversion/83184 "2023-11-28T11:19:55Z")

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This is a peace of the flow which shows my problem: Sunrise and sunset comes in that format: "Sat Nov 25 2023 19:57:52 GMT+0100" and I need a timestamp of this format in oder to calculate the time difference. (durati…

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## [How to access context in a change node using the J: method](https://discourse.nodered.org/t/how-to-access-context-in-a-change-node-using-the-j-method/83241)

<div class="topic-metadata">

**Author:** [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Replies:** 3\
**Last updated:** [28 November 2023 11:16 UTC](https://discourse.nodered.org/t/how-to-access-context-in-a-change-node-using-the-j-method/83241 "2023-11-28T11:16:42Z")

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Sorry, I know I've asked before but it is possible. I want to do some maths on a context but can't remember how to do that trick. I seem to remember in the change node you set it something like: J: flow.get("something…

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## [Change multiple svg elements color?](https://discourse.nodered.org/t/change-multiple-svg-elements-color/83244)

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**Author:** [@Kliurka](https://discourse.nodered.org/u/Kliurka)\
**Replies:** 2\
**Last updated:** [28 November 2023 10:22 UTC](https://discourse.nodered.org/t/change-multiple-svg-elements-color/83244 "2023-11-28T10:22:59Z")

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howto change multiple svg elements color? like that

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## [Can this be done with bluetooth?](https://discourse.nodered.org/t/can-this-be-done-with-bluetooth/83213)

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**Author:** [@EaB11](https://discourse.nodered.org/u/EaB11)\
**Replies:** 7\
**Last updated:** [28 November 2023 10:15 UTC](https://discourse.nodered.org/t/can-this-be-done-with-bluetooth/83213 "2023-11-28T10:15:10Z")

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i am looking at getting a small motorized dolly for a camera (model is Neewer DL300).. it uses bluetooth to connect to an app on the phone where the user can set its movement direction (either left or right) and also spe…

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## [Reading in file missing parts](https://discourse.nodered.org/t/reading-in-file-missing-parts/83026)

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**Author:** [@sages](https://discourse.nodered.org/u/sages)\
**Replies:** 8\
**Last updated:** [28 November 2023 08:57 UTC](https://discourse.nodered.org/t/reading-in-file-missing-parts/83026 "2023-11-28T08:57:54Z")

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greetings,I have to convert a absolutely massive json string to a javascript object using the default JSON NODE in multiple steps. 1.The string is read in from the filesystem using the default read file block with th…

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## [500 parallel flow in Nodered](https://discourse.nodered.org/t/500-parallel-flow-in-nodered/83237)

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**Author:** [@shershah](https://discourse.nodered.org/u/shershah)\
**Replies:** 4\
**Last updated:** [28 November 2023 08:53 UTC](https://discourse.nodered.org/t/500-parallel-flow-in-nodered/83237 "2023-11-28T08:53:19Z")

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Hi All, I am trying to find if we can create 500 parallel flow in Nodered. Can we? Will there be any performance issue? If it is feasible, how can we maintain queue to avoid data loss? Regards, Shershah

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## [Integrate node-red editor in angular project](https://discourse.nodered.org/t/integrate-node-red-editor-in-angular-project/83220)

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**Author:** [@norchenne](https://discourse.nodered.org/u/norchenne)\
**Replies:** 0\
**Last updated:** [27 November 2023 13:08 UTC](https://discourse.nodered.org/t/integrate-node-red-editor-in-angular-project/83220 "2023-11-27T13:08:14Z")

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Hello, I am required to integrate node-red editor in angular project which I already did using an Iframe, but could I also authenticate the node-red user using the angular session token? If so, could you please give m…

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## [Lead/lag pump failover](https://discourse.nodered.org/t/lead-lag-pump-failover/83209)

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**Author:** [@Automata](https://discourse.nodered.org/u/Automata)\
**Replies:** 5\
**Last updated:** [28 November 2023 01:59 UTC](https://discourse.nodered.org/t/lead-lag-pump-failover/83209 "2023-11-28T01:59:42Z")

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happy holiday weekend everyone, running into some trouble getting a pump failover flow to work. ive tried numerouse configurations. this has gotten me the closest. what im trying to achieve is having the lead pump always…

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## [How to extract a value](https://discourse.nodered.org/t/how-to-extract-a-value/83233)

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**Author:** [@telescopio](https://discourse.nodered.org/u/telescopio)\
**Replies:** 12\
**Last updated:** [27 November 2023 23:56 UTC](https://discourse.nodered.org/t/how-to-extract-a-value/83233 "2023-11-27T23:56:05Z")

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11/27/2023, 4:32:57 PMnode: debug 57 Need help to extract the rF to show on a text node true : msg.payload : Object object id: 100 tC: 26.2 tF: 79.2

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## [Dynamic name for variables,based for example on \_\_msgid\_\_](https://discourse.nodered.org/t/dynamic-name-for-variables-based-for-example-on-msgid/83226)

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**Author:** [@aguida79](https://discourse.nodered.org/u/aguida79)\
**Replies:** 8\
**Last updated:** [27 November 2023 23:30 UTC](https://discourse.nodered.org/t/dynamic-name-for-variables-based-for-example-on-msgid/83226 "2023-11-27T23:30:22Z")

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Hi everyone, I want to know if there is a way to define a variable with a dynamic part in the name. For example, I can define a flow context variable with a dynamic name, like this: flow.set('value'+\_msgid\_,"test"); …

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## [Is there a more elegant solution for this pattern](https://discourse.nodered.org/t/is-there-a-more-elegant-solution-for-this-pattern/83230)

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**Author:** [@escamoteur](https://discourse.nodered.org/u/escamoteur)\
**Replies:** 2\
**Last updated:** [27 November 2023 21:19 UTC](https://discourse.nodered.org/t/is-there-a-more-elegant-solution-for-this-pattern/83230 "2023-11-27T21:19:41Z")

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I have repeated a pattern like the above because I want to trigger a message with latest value of a Sensor either when the state of the sensor changes or, because of some other trigger. It would be nice if there were …

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## [How to reverse a value?](https://discourse.nodered.org/t/how-to-reverse-a-value/83089)

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**Author:** [@eli5](https://discourse.nodered.org/u/eli5)\
**Replies:** 34\
**Last updated:** [27 November 2023 13:22 UTC](https://discourse.nodered.org/t/how-to-reverse-a-value/83089 "2023-11-27T13:22:16Z")

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I have a soil moisture sensor that gives me values from 2850 (dry) to 1250 (in water). I would like to convert these into percentage values, i.e. 0-100%. My problem is that I can only convert from small to large with th…

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## [Send File Through WhatsApp](https://discourse.nodered.org/t/send-file-through-whatsapp/83216)

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**Author:** [@Mohamed\_1711](https://discourse.nodered.org/u/Mohamed_1711)\
**Replies:** 6\
**Last updated:** [27 November 2023 13:18 UTC](https://discourse.nodered.org/t/send-file-through-whatsapp/83216 "2023-11-27T13:18:15Z")

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Can I send File through WhatsApp Using Any Module ???

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## [Remove "maximum number of catches"](https://discourse.nodered.org/t/remove-maximum-number-of-catches/83187)

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**Author:** [@mrark](https://discourse.nodered.org/u/mrark)\
**Replies:** 15\
**Last updated:** [27 November 2023 10:01 UTC](https://discourse.nodered.org/t/remove-maximum-number-of-catches/83187 "2023-11-27T10:01:14Z")

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Good evening everyone. I'm working on a flow to create a bot to retrieve a lot of datas from a website: it loops a http request via the nbrowser node, and each time it retrieves the data by doing a few steps. For reason…

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## [How to replace number by variable in payload\[6\]](https://discourse.nodered.org/t/how-to-replace-number-by-variable-in-payload-6/83207)

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**Author:** [@jhoepffner](https://discourse.nodered.org/u/jhoepffner)\
**Replies:** 2\
**Last updated:** [26 November 2023 21:33 UTC](https://discourse.nodered.org/t/how-to-replace-number-by-variable-in-payload-6/83207 "2023-11-26T21:33:37Z")

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Hello, I want to select various part of a list using global variable. I have a global variable named 'Cue' How can I replace the 6 in Payload\[6\] by the value of Cue? I have tried a function node with: var count = gl…

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## [How to adjust volume on RasPi](https://discourse.nodered.org/t/how-to-adjust-volume-on-raspi/83165)

<div class="topic-metadata">

**Author:** [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Replies:** 16\
**Last updated:** [26 November 2023 21:27 UTC](https://discourse.nodered.org/t/how-to-adjust-volume-on-raspi/83165 "2023-11-26T21:27:10Z")

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(Sort of from the other thread but new question) I have since discovered that a lot of the problem was the BLUE TOOTH part of the speaker. Got a 3.5mm cable and it works now a lot better than if using BT. The speaker …

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## [How can I send "chunked" http responses?](https://discourse.nodered.org/t/how-can-i-send-chunked-http-responses/83204)

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**Author:** [@Stwissel](https://discourse.nodered.org/u/Stwissel)\
**Replies:** 0\
**Last updated:** [26 November 2023 18:57 UTC](https://discourse.nodered.org/t/how-can-i-send-chunked-http-responses/83204 "2023-11-26T18:57:34Z")

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I have a node returning multiple JSON objects from a query in sequence. I want to trigger that query from a http node: http-in -\> my node -\> http response. The http response node it set to a header property "transfer-e…

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## [How to reset add node](https://discourse.nodered.org/t/how-to-reset-add-node/83166)

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**Author:** [@rmystique](https://discourse.nodered.org/u/rmystique)\
**Replies:** 10\
**Last updated:** [26 November 2023 18:25 UTC](https://discourse.nodered.org/t/how-to-reset-add-node/83166 "2023-11-26T18:25:25Z")

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How do I reset a add node, Ideally I want it to reset on the 28th of every month?

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## [Npm xlsx how to write msg.payload to xls file](https://discourse.nodered.org/t/npm-xlsx-how-to-write-msg-payload-to-xls-file/83191)

<div class="topic-metadata">

**Author:** [@Mick](https://discourse.nodered.org/u/Mick)\
**Replies:** 3\
**Last updated:** [26 November 2023 15:32 UTC](https://discourse.nodered.org/t/npm-xlsx-how-to-write-msg-payload-to-xls-file/83191 "2023-11-26T15:32:55Z")

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I am working npm xlsx and want to create a xlsx file on my local device from the json output. I have gotten npm xlsx to load and I am using an example I found online to test. I get nothing when I run the function. l…

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## [Node serial port, how to perform crc check](https://discourse.nodered.org/t/node-serial-port-how-to-perform-crc-check/82425)

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**Author:** [@henkkas](https://discourse.nodered.org/u/henkkas)\
**Replies:** 14\
**Last updated:** [26 November 2023 09:12 UTC](https://discourse.nodered.org/t/node-serial-port-how-to-perform-crc-check/82425 "2023-11-26T09:12:06Z")

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I am using the node 'serial in' from node-red-node-serial-port, to read data from the smart meter. This node is connected to a function node to process the data coming from the smart meter. It works well, but sometimes…

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## [Pass subflow info under the node info](https://discourse.nodered.org/t/pass-subflow-info-under-the-node-info/83172)

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**Author:** [@usky73](https://discourse.nodered.org/u/usky73)\
**Replies:** 9\
**Last updated:** [26 November 2023 07:47 UTC](https://discourse.nodered.org/t/pass-subflow-info-under-the-node-info/83172 "2023-11-26T07:47:14Z")

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Hi, just discovered the subflow feature and it is great. I would like to go further and have the same feature than some other nodes, means show the main values under the node icon like this home assistant node, like the…

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## [Please help me "moving" Node-Red docker to docker compose. (retaining data)](https://discourse.nodered.org/t/please-help-me-moving-node-red-docker-to-docker-compose-retaining-data/83188)

<div class="topic-metadata">

**Author:** [@AndKe](https://discourse.nodered.org/u/AndKe)\
**Replies:** 3\
**Last updated:** [25 November 2023 23:20 UTC](https://discourse.nodered.org/t/please-help-me-moving-node-red-docker-to-docker-compose-retaining-data/83188 "2023-11-25T23:20:42Z")

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My nodered is currently based on docker run -it -p 1880:1880 -p 161:161/udp -p 162:162/udp --name noderednew nodered/node-red docker start noderednew yes, I am aware of Running under Docker : Node-RED if I added this…

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## [Newbie question](https://discourse.nodered.org/t/newbie-question/83176)

<div class="topic-metadata">

**Author:** [@mforbiz](https://discourse.nodered.org/u/mforbiz)\
**Replies:** 3\
**Last updated:** [25 November 2023 18:04 UTC](https://discourse.nodered.org/t/newbie-question/83176 "2023-11-25T18:04:40Z")

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Hi. Before to start a learning path with Node-RED, I'd like to know if it may be useful to my needs. I'd like to create a BLE-MQTT gateway to install on Home Assistant that can act as a central device (BLE client) so t…

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