1 to 3 HUB Expansion Unit

cerocca

Hi there,

I am planning to use the "1 to 3 HUB Expansion Unit" (https://m5stack-store.myshopify.com/products/mini-hub-module) in my project where I have some Seeedstudio grove modules driven by a 3.3V Arduino.

My question is: which is the range of power supply which can be given to the "5V" pin?
If I supply it with 3.3V (my whole system is 3.3V, no 5V around) will it work?

Sorry for the silly question but I didn't find this info anywhere.

thanks to who will help me!

felmue

Hello @cerocca

the 1 to 3 HUB Expansion Unit doesn't have any active elements (like ICs etc.) in it - it simply 'forks' the connection into three. Or in other words, it doesn't matter to the 1 to 3 HUB Expansion Unit whether you use the 5 V pin with 3.3 V or 5 V. (That only matters to the modules you connect to it.)

For reference - check the schematic.

Thanks
Felix

cerocca

Hi @felmue

and thanks for your reply, appreciated. I knew it was simple but I wanted confirmation :)
Regardless of this, thanks for pointing me out where to find all documentation, including schematics.

So I have another question: are the modules "possible to open"?
I mean, I saw some modules interesting for my project (heart rate sensor) and their schematic show that there is a LDO regulator from the +5V to the +3v3 of the IC.
I was wondering if it was possible to safely open the white plastic package, bypass the LDO so that I can feed the sensor directly with the +3v3 I have on the I2C VCC line.

Thanks if you (or anybody else!) can answer my doubt.

ajb2k3

@cerocca said in 1 to 3 HUB Expansion Unit:

Hi @felmue

and thanks for your reply, appreciated. I knew it was simple but I wanted confirmation :)
Regardless of this, thanks for pointing me out where to find all documentation, including schematics.

So I have another question: are the modules "possible to open"?
I mean, I saw some modules interesting for my project (heart rate sensor) and their schematic show that there is a LDO regulator from the +5V to the +3v3 of the IC.
I was wondering if it was possible to safely open the white plastic package, bypass the LDO so that I can feed the sensor directly with the +3v3 I have on the I2C VCC line.

Thanks if you (or anybody else!) can answer my doubt.

@cerocca said in 1 to 3 HUB Expansion Unit:

Hi @felmue

and thanks for your reply, appreciated. I knew it was simple but I wanted confirmation :)
Regardless of this, thanks for pointing me out where to find all documentation, including schematics.

So I have another question: are the modules "possible to open"?
I mean, I saw some modules interesting for my project (heart rate sensor) and their schematic show that there is a LDO regulator from the +5V to the +3v3 of the IC.
I was wondering if it was possible to safely open the white plastic package, bypass the LDO so that I can feed the sensor directly with the +3v3 I have on the I2C VCC line.

Thanks if you (or anybody else!) can answer my doubt.

dont bypass the ldo!
units have a supply voltage of 5v and if you bypass the ldo you will put 5v into a 3v3 device.

felmue

Hello @cerocca

I don't have that particular unit, but I think it is possible to directly power it from 3.3 V. However you might also need to bypass the level shifters.

@ajb2k3 : the described scenario only uses 3.3 V for everything. The question is whether the unit can be powered by 3.3 V (bypassing the LDO) instead of 5 V (with the LDO).

Thanks
Felix

cerocca

Thanks to both :)

@ajb2k3 : as written also by @felmue I want to power all my system with 3.3V so there won't be around any 5V at all !

Of course I need to check the specific schematic in order to understand what to bypass, but my question was if the white enclosure of M5Stack modules (like the I2C hub, or the heart rate sensor) can be easily open - without damaging / breaking them - or not (is there something like a screw?).

Any clue about that?

thanks!