Tuesday, April 9, 2013

Raspberry Pi Model A, provides less power through the USB port

I just received my Raspberry Pi Model A. I have one Model B before and the intended use for the Model A is to be placed on the robot together with the custom Arduino I build specifically for the purpose. I bought the board from Lawicel-Shop, and they delivered fast as usual.

Model A to the left, Model B to the right (on case bottom)
The Model A is a scaled down version of the Model B. It has only 256Mb of memory, only one USB port instead of two, and lacks the Ethernet port. But it consumes less power, making it ideal for my robotic purposes...

Testing the Model A using a powered USB hub

I tried the board with Raspian OS, same SD card I have used with my other Pi. A definitive problem is that the USB port of the Model A seem to provide less current than that of the Model B!
This meant the USB-wifi could not be powered directly from the Model A while it worked fine on Model B. It works if I connect it through the powered USB-hub.
This becomes a problem for me since I intend to use it on my robot, and use the WIFI connection to program it, and it is kind of tricky to use a powered USB-hub on the robot...

I guess it is possible to buy a battery powered USB hub, but the space is quite limited on the robot...
The Custom Arduino board for RPi (connected to Model B)

Running Arduino IDE on the Pi and my two robots below...
The USB wifi that does not work on the Model A unless I connect it to a powered USB hub.

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