# Any built-in function to read Vin?

**URL:** <https://forum.arduino.cc/t/any-built-in-function-to-read-vin/688960>\
**Category:** Nano 33 BLE\
**Created:** [December 29, 2020, 10:06am UTC](https://forum.arduino.cc/t/any-built-in-function-to-read-vin/688960 "2020-12-29T10:06:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![AK51school](https://avatars.discourse-cdn.com/v4/letter/a/977dab/32.png) [@AK51school](https://forum.arduino.cc/u/AK51school)\
**Post date:** [December 29, 2020, 10:06am UTC](https://forum.arduino.cc/t/any-built-in-function-to-read-vin/688960/1 "2020-12-29T10:06:35Z")

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Hi,

I need to keep the Nano 33 BLE running for 1.5 hr. I have the 3.7V battery connected to the board and it runs ok.  
If I want to check the Vin voltage, do I need to make a voltage divider to analogread the Vin voltage? Or is there a built-in function?

Thanks,

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**Author:** ![Klaus\_K](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/klaus_k/32/626942_2.png) [@Klaus\_K](https://forum.arduino.cc/u/Klaus_K)\
**Post date:** [December 29, 2020, 11:31pm UTC](https://forum.arduino.cc/t/any-built-in-function-to-read-vin/688960/2 "2020-12-29T23:31:05Z")

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You can find the schematic of the Nano 33 BLE in the store under DOCUMENTATION.

> **[Arduino Nano 33 BLE](https://store.arduino.cc/products/arduino-nano-33-ble)**
>
> The Nano 33 BLE (without headers) is Arduino’s 3.3V compatible board in the smallest available form factor: 45x18mm! The Arduino Nano 33 BLE is a completely new board on a well-known form factor. It comes with an embedded 9 axis inertial sensor what...

The Vin pin is only connected to the power converter. Vin is much higher than what the Arduino 33 BLE I/O can handle. 3.3V that is what the name comes from. So, you will need to use a voltage divider.

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [May 7, 2021, 11:57am UTC](https://forum.arduino.cc/t/any-built-in-function-to-read-vin/688960/3 "2021-05-07T11:57:11Z")

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Closed on May 7, 2021, 11:57am UTC