# Extract voltage value only from ADS1x15
**URL:** https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647
**Category:** General
**Created:** [10 November 2020 05:09 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647 "2020-11-10T05:09:49Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@rmystique](https://discourse.nodered.org/u/rmystique)
#### Post date: [10 November 2020 05:09 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/1 "2020-11-10T05:09:49Z")
So i have the a/d outputing this: { ADS1115 • I2C\_ADDRESS\_0x48 • Channel A0-GND • Voltage: 3.2901004058961765 }
But i just want the message.payload to be the numerical voltage value so i can drive a guage with it, how?
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### Author:  [@kuema](https://discourse.nodered.org/u/kuema)
#### Post date: [10 November 2020 05:31 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/2 "2020-11-10T05:31:15Z")
That can be achieved by the `change` node, as documented here: [https://nodered.org/docs/user-guide/messages#changing-message-properties](https://nodered.org/docs/user-guide/messages#changing-message-properties)
Something like `msg.payload.Voltage` in the "to" line should do the trick. Be aware that object properties are case-sensitive.
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [10 November 2020 09:08 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/3 "2020-11-10T09:08:47Z")
If that doesn't work then feed the message into a debug node and show us exactly what it shows.
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### Author:  [@rmystique](https://discourse.nodered.org/u/rmystique)
#### Post date: [11 November 2020 01:54 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/4 "2020-11-11T01:54:29Z")
Here is the debug result
{"ADS1115 • I2C\_ADDRESS\_0x48 • Channel A0-GND • Voltage":3.2901004058961765}
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [11 November 2020 09:18 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/5 "2020-11-11T09:18:27Z")
If you look in the node-red docs [Working with Messages](https://nodered.org/docs/user-guide/messages) (as @kuema suggested) it shows you how you can use the buttons in the debug pane get the path to a property. In this case the path will be something like
`msg.payload["ADS1115 • I2C_ADDRESS_0x48 • Channel A0-GND • Voltage"]`
I would first attempt to persuade whatever node or device you are getting that from to give you a more useful property name such as "voltage". Then you would be able to use `msg.payload.voltage` which is much easier to type. If you want to include information about what the value refers to then the convention is to use the topic for that, and I wouldn't use special characters in there if you can avoid it, it just makes life more difficult.
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### Author:  [@rmystique](https://discourse.nodered.org/u/rmystique)
#### Post date: [12 November 2020 04:32 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/6 "2020-11-12T04:32:05Z")
> [@Colin](#):
>
> msg.payload["ADS1115 • I2C\_ADDRESS\_0x48 • Channel A0-GND • Voltage"]
That did the trick , thank you
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [11 January 2021 04:32 UTC](https://discourse.nodered.org/t/extract-voltage-value-only-from-ads1x15/35647/7 "2021-01-11T04:32:06Z")
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