# Reading DS3231 RTC in Node Red
**URL:** https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133
**Category:** Dashboard
**Created:** [31 January 2021 21:06 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133 "2021-01-31T21:06:25Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@wa9mvz](https://discourse.nodered.org/u/wa9mvz)
#### Post date: [31 January 2021 21:06 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/1 "2021-01-31T21:06:26Z")
Is there a simple way to input time to display on the dashboard from the DS3231 RTC module? Using the I2C IN node, I can see and read what looks like seconds and minutes data using the 00 and 01 commands in those nodes. The SECONDS update to a new number every second, but it isn't decimal. The seconds start at 0 and count to 9 then jump to 16. It displays erratically up to 100 and then the minutes digit changes.
So now I suppose I have to decode this somehow to decimal to display a real looking clock on the dashboard.
This seem very awkward. Is there a simpler way?
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### Author:  [@dceejay](https://discourse.nodered.org/u/dceejay)
#### Post date: [31 January 2021 21:27 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/2 "2021-01-31T21:27:43Z")
I think that is called binary coded decimal. Been ages since I’ve seen it but I’m sure google will help
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### Author:  [@edje11](https://discourse.nodered.org/u/edje11)
#### Post date: [31 January 2021 21:35 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/3 "2021-01-31T21:35:35Z")
Looking at the datasheet the upper 4 bits are the 10 seconds and the lower the seconds, same for the minutes etc.
I don't know Javascript good enough for bit manipulation.
In C we AND the right 4 bits to get the seconds value and then shift the left 4 bits to right to get 10th seconds value.
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### Author:  [@wa9mvz](https://discourse.nodered.org/u/wa9mvz)
#### Post date: [31 January 2021 21:51 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/4 "2021-01-31T21:51:59Z")
Yes, I recognize it as HEXADECIMAL, and I could certainly decode it in C but that really wasn't my question.
This was very easy to do on an Arduino so I'll rephrase my question: isn't there an easier way to read this very common device (DS3231 RTC) in NODE RED? Surely someone has done this before.
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### Author:  [@edje11](https://discourse.nodered.org/u/edje11)
#### Post date: [31 January 2021 22:02 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/5 "2021-01-31T22:02:13Z")
Try this in a function node
```auto
var val = msg.payload
msg.payload= ((Math.floor(val/16)*10)+val%16)
return msg;
```
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### Author:  [@wa9mvz](https://discourse.nodered.org/u/wa9mvz)
#### Post date: [31 January 2021 22:39 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/6 "2021-01-31T22:39:19Z")
I guess I gotta do what I gotta do.
Thanks for that snippet edje11 ... it decodes and displays perfectly now.
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### Author:  [@Andrei](https://discourse.nodered.org/u/Andrei)
#### Post date: [1 February 2021 00:01 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/7 "2021-02-01T00:01:10Z")
> [@wa9mvz](#):
>
> isn't there an easier way to read this very common device (DS3231 RTC) in NODE RED? Surely someone has done this before.
Did you check NPM for a node.js package ? Apparently there are two of them who are up to the job.
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### Author:  [@wa9mvz](https://discourse.nodered.org/u/wa9mvz)
#### Post date: [1 February 2021 00:27 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/8 "2021-02-01T00:27:33Z")
I did search, but nothing returned. Could you be more specific for my search?
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### Author:  [@Andrei](https://discourse.nodered.org/u/Andrei)
#### Post date: [1 February 2021 20:18 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/9 "2021-02-01T20:18:11Z")
Only today I could have a better look on them. Both are lacking a Github repository. It seems to me they are abandoned. You probably did the right choice on handling them directly with I2C node, reading the internal registers.
> **[@nanomatic/ds3231](https://www.npmjs.com/package/@nanomatic/ds3231)**
>
> RTC DS3231 implementation for the Raspberry PI 4 + temperature reading 🌡
> **[ds3231-rtc](https://www.npmjs.com/package/ds3231-rtc)**
>
> This package is to use DS3231 realtime clock module with nodejs
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### Author:  [@wa9mvz](https://discourse.nodered.org/u/wa9mvz)
#### Post date: [4 February 2021 16:19 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/10 "2021-02-04T16:19:45Z")
Well, I seemed to have really messed something up. All was working well until I followed some tutorials about how to set the HWCLOCK.
Now, when I scan using 'i2cdetect -y 1' it shows ports 57 and a UU in port 68 where the DS3231 is supposed to be. The 'UU' is supposedly a conflict but the commands 'sudo hwclock -r' and sudo hwclock -w' entered into the terminal seem to work.
Yet using the i2c Scan node, a port 87 appears. I get errors when I try to use the 'i2c in' nodes to connect to 57 or 68. It will connect to the phantom port 87 but I only receive '255' in the msg.
Can someone tell me what I've messed up here?
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [18 February 2021 16:20 UTC](https://discourse.nodered.org/t/reading-ds3231-rtc-in-node-red/40133/11 "2021-02-18T16:20:09Z")
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