# UDP input for Temp monitor

**URL:** <https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917>\
**Category:** General\
**Created:** [6 May 2026 03:27 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917 "2026-05-06T03:27:39Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Shorts](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shorts](https://discourse.nodered.org/u/Shorts)\
**Post date:** [6 May 2026 03:27 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/1 "2026-05-06T03:27:39Z")

</div>

Hi,  
I have a device sending temperature updates via UDP which I want to display on a Dashboard. The data is as follows:  
Enc Data: 3a203134300d0a02021000a6170000  
It is only 2 digits out of this string I require and they are near the center of the number.  
How do I get only the ENC data.

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [6 May 2026 08:16 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/2 "2026-05-06T08:16:46Z")

</div>

Hi, welcome to the forum.

unfortunately you have not provided enough detail to really help you.

I would use the buffer-parser package (its build for helping you extract and convert values from a buffer (byte data)) which is what you are trying to achieve.

But if you tell us which digits and what format the number is, we can provide you a working demo.  
Do you have a specification of that data format?

---

<div class="post-metadata">

**Author:** ![Shorts](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shorts](https://discourse.nodered.org/u/Shorts)\
**Post date:** [6 May 2026 10:01 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/3 "2026-05-06T10:01:13Z")

</div>

Hi Steve,

Thanks for the reply.

The data packets look like this:

Frame 571: 73 bytes on wire (584 bits), 73 bytes captured (584 bits)

Ethernet II, Src: ZenitelNorwa\_0e:0f:f2 (00:13:cb:0e:0f:f2), Dst: ZenitelNorwa\_0e:21:be (00:13:cb:0e:21:be)

Internet Protocol Version 4, Src: 192.168.1.55, Dst: 192.168.1.57

User Datagram Protocol, Src Port: 5035, Dst Port: 5035

Source Port: 5035

Destination Port: 5035

\<Source or Destination Port: 5035\>

\<Source or Destination Port: 5035\>

Length: 39

Checksum: 0xc290 [unverified]

[Checksum Status: Unverified]

[Stream index: 0]

[Timestamps]

UDP payload (31 bytes)

SKYPE

ID: 0x4441

0101 .... = Unknown: 0x5

.... 0011 = Type: Fragment/Forward/Resend (0x3)

Num: 0x56

Unk1: 0x02000d00

IV: 0x0000536f

CRC: 0x75726365

Enc Data: 3a203134300d0a02021000a6170000

[Community ID: 1:uDIU6EqA5BKIIfvo+gTUV9f0SUg=]

The 2 digits I require are in red (a6)

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [6 May 2026 11:17 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/4 "2026-05-06T11:17:48Z")

</div>

Assuming it is always the 11th byte then you can simply pull it out and format it using buffer parser node (install that using palette manager)

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/5/751fe500fce1140d7ca3a016fd291078cb9f2fcc.png)

```json
[
    {
        "id": "91de98fbc3639adf",
        "type": "inject",
        "z": "7ecf422396bf31b4",
        "name": "udp data",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "3a203134300d0a02021000a6170000",
        "payloadType": "str",
        "x": 990,
        "y": 1220,
        "wires": [
            [
                "c8437066170d375a"
            ]
        ]
    },
    {
        "id": "c8437066170d375a",
        "type": "buffer-parser",
        "z": "7ecf422396bf31b4",
        "name": "",
        "data": "payload",
        "dataType": "msg",
        "specification": "spec",
        "specificationType": "ui",
        "items": [
            {
                "type": "uint8",
                "name": "temp",
                "offset": 11,
                "length": 1,
                "offsetbit": 0,
                "scale": "0",
                "mask": ""
            },
            {
                "type": "uint8",
                "name": "tempScaled",
                "offset": 11,
                "length": 1,
                "offsetbit": 0,
                "scale": "0.1",
                "mask": ""
            },
            {
                "type": "hex",
                "name": "tempHex",
                "offset": 11,
                "length": 1,
                "offsetbit": 0,
                "scale": "0.1",
                "mask": ""
            },
            {
                "type": "buffer",
                "name": "raw",
                "offset": 11,
                "length": 1,
                "offsetbit": 0,
                "scale": "0.1",
                "mask": ""
            }
        ],
        "swap1": "",
        "swap2": "",
        "swap3": "",
        "swap1Type": "swap",
        "swap2Type": "swap",
        "swap3Type": "swap",
        "msgProperty": "payload",
        "msgPropertyType": "str",
        "resultType": "keyvalue",
        "resultTypeType": "return",
        "multipleResult": false,
        "fanOutMultipleResult": false,
        "setTopic": true,
        "outputs": 1,
        "x": 1160,
        "y": 1220,
        "wires": [
            [
                "42cf58dc63b107c2"
            ]
        ]
    },
    {
        "id": "42cf58dc63b107c2",
        "type": "debug",
        "z": "7ecf422396bf31b4",
        "name": "debug 9",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 1370,
        "y": 1220,
        "wires": []
    },
    {
        "id": "679581b7087bfb40",
        "type": "global-config",
        "env": [],
        "modules": {
            "node-red-contrib-buffer-parser": "3.2.2"
        }
    }
]

```

---

<div class="post-metadata">

**Author:** ![Shorts](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shorts](https://discourse.nodered.org/u/Shorts)\
**Post date:** [8 May 2026 03:54 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/5 "2026-05-08T03:54:44Z")

</div>

Thanks for the reply. I have deployed that flow and debug shows it only getting "a6" returned as the value. New to node-red so i probably have done something else wrong. This is deployed on a pi-3 with a screen so i am trying to convert that output to drive a display readout.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [6 August 2026 03:55 UTC](https://discourse.nodered.org/t/udp-input-for-temp-monitor/100917/6 "2026-08-06T03:55:30Z")

</div>

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.