Voltage when using USB Splitter

[jungletemple]

I have a USB splitter like this one: http://i.imgur.com/yBQ5oPz.jpg
On the female end, I have an Arduino that requires 5V.
Male end #1 is always connected to a 5V power source, to power the Arduino.

I want to use male end #2 to occasionally connect my laptop to upload a new program to the Arduino.

My question is: is the Arduino going to be damaged if both male end #1 and male end #2 are connected at the same time? (#1= 5V power supply , #2=laptop USB (5v))

 

[Bluejets]

I wouldn't even think about it.

 

[jungletemple]

So you don't think it would be an issue?
I'm not sure how voltage/current work, so I'm relying on you guy's knowledge

 

[dorke]

What you have is a Y-cable not a proper USB-splitter.
In that Y-cable powering from the 2 males will cause a +5v conflict,don't use it.

Why not power the Arduino from the laptop using a standard USB cable( both power and doanload) ?

 

[jungletemple]

I only use the computer occasionally to upload new programs to the Arduino.
It's main power source is from the other "Y" end.

what kind of conflict will it create? Will it add up and provide +10v? sorry if it's a dumb question....

 

[(*steve*)]

you may have current flowing from one power supply to the other. This is more likely to be a problem for your PSU than your laptop as the ports SHOULD be protected.

another issue is whether your power supply makes any connections to the data pins (some do this to indicate available charge rate). Any connections of this type may confuse the laptop or make USB communication problematic.

A third issue is the possibility of ground bring at different potentials on the PSU and the laptop. This is not likely but can be very may. It's worth comparing them and seeing if any current can flow (these currents are not usually protected against).

I think the chances of damage to anything expensive are probably low but not zero.

Preferably I would disconnect the data lines from your PSU and the +5v from the laptop.

 

[jungletemple]

Sounds good.
I have the option of NOT using the Y-cable; I'll just use a single cable instead, unplug it and connect it to my laptop when needed. It's more cumbersome every time I have to do it, but at least it's safe.

thank you everyone!

 

[Martaine2005]

Why can't you use a USB hub?

Martin

 

[BobK]

Because a USB hub connects multiple clients to one host. He wants to connect one client to multiple hosts.

Edited to add: Actually to a host port and a charging port.

Bob