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I'm really new at electronics and wiring, so please be kind. Coding is my stuff, but I'm trying to learn something here.

I'm working with a project to store the movements of a skateboard through a MPU 9235 and the idea is to save the output of the sensor to a MicroSD.

I have both components and acquired a LiPO 3.7v 400mAh to take everything off the protoboard and attach at the bottom of the skateboard.

The code is working, everything code wise is working ok, but I'm strugging to understand how to power both MicroSD module and MPU9235, since both have the VCC pin (VDD in some versions).

The current connections are replicated in Fritzing. Only replacing Arduino Uno for an Arduino Nano, and the MPU 6050 from the picture for a MPU9235.

enter image description here

My first thought was to connect the LiPo battery into VIN and GND pins of Nano. From there I believe that I can wire up the 3V3 output directly to VCC from MPU9235.

But what about the MicroSD module?

How would I power its VCC pin since I have no 3V3 pin left? I read that it's not right to use a digital pin as power output.

How can I connect two components that needs power from external source?

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VIN takes 6-12v and it sends it through the on board regulator - so that is the best way to power the nano.

If you take a wire from the 3v3 pin and split it (solder two wires to one) then you will have two 3v3 feeds to wire to your two devices. This will be the same as you have to do for the Gnd connections, back to the Nano.

Does that make sense? (if not I'll try and draw you something).

  • Yes it does. It didn't make sense before because I did think that splitting a wire would provide half of 3.3v. Thing is, the board will always try to provide 3.3v for the output wire and if I ended up having too many devices connected to it, to this 3.3v output wire, the battery life will be low. Is that correct? – Fabiano Araujo Jul 16 '18 at 13:42
  • "The wire" will supply 3.3v to all devices connected, but the board will have to 'split' the maximum current that it can supply between the devices. Each device will get UP TO the maximum mA it requires, but that may not be enough for it to functions. I THINK you battery will drain faster, the more devices you have but you can get 10AH+ lipo batteries that aren't much bigger than a AA battery. – Code Gorilla Jul 16 '18 at 14:19

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