Matrix user forums

I have an EB385 on order and have the following question.

If I have the EB385 phyiscally attached but not in use, can I still power the Pi directly rather than through the EB385.
The reason I ask is my Pi will spend 90% of its time on my desk running einstein@home and the power cable is threaded through a hole in the desk so not easy to remove. When I go to use the EB385 for experiments with E-Blocks I want to remove the Pi from my desk and power it via the EB385 and a Matrix power supply.

Thanks

Hello,

That's great, its a fantastic little board for playing with E-blocks.

With the EB385 attached you can power the pi using either the standard USB supply or the DC supply socket on the EB385.

I have some demo Python code if you need an example on how to use the I/O or the UART.

Let us know how you get on

Benj wrote:Hello,
With the EB385 attached you can power the pi using either the standard USB supply or the DC supply socket on the EB385.

But thats not what I want to do. I want to power the Pi via its power input, but with the EB385 attached but not in use. Is that possible?

Hi Keith,

But thats not what I want to do. I want to power the Pi via its power input, but with the EB385 attached but not in use. Is that possible?

Yes that is possible, my last answer was trying to get this across but probably overcomplicated it

Hi Keith
The adaptor is a nice little board.
I wrote a small article on the RPi adaptor when it was first released, and included some basic python scripts.
(Note to self, must get the Pi out and do some more stuff with it. LOL)

http://www.matrixtsl.com/mmforums/viewt ... +raspberry

You will see in the latter photos in my article I added a small heat sink to the 3 pin regulator on the adaptor board.
I don't really think it was getting hot enough to cause problems, but it was for piece of mind more than anything.
It depends on what sort of thing you have plugged in to the e-block ports too.

My board has arrived and just read through the instructions for assembling the case. Find it very difficult to believe that the case APPEARS NOT TO ALLOW you to remove/insert the SD card of the Pi. What sort of non design is that. VERY VERY disappointing.

Hi Keith,

I believe this might have been done on purpose

A: To prevent students from taking the SD cards
B: The files on the SD card (as far as I am aware) are not accessible outside of the Linux OS running on the Pi so once the OS is installed and running there is little need to remove the card
C: An easy way to transfer data is a USB dongle

Maybe it would be good if we offered an option of case. If you like I can see about getting you a replacement case with a slot for the card machined and sent out for you.

Benj wrote:Hi Keith,

I believe this might have been done on purpose

A: To prevent students from taking the SD cards
B: The files on the SD card (as far as I am aware) are not accessible outside of the Linux OS running on the Pi so once the OS is installed and running there is little need to remove the card
C: An easy way to transfer data is a USB dongle

Maybe it would be good if we offered an option of case. If you like I can see about getting you a replacement case with a slot for the card machined and sent out for you.

Hi Ben yes an option on the case to either have access to the SD card or not would be a good idea.
Yes please if you can supply a replacement part with a machined slot that would be great.
Its not for transfering data that I need access to the SD its in case It gets corrupted by a power failure
and we get a lot of power failures where I live.

I have a problem in that the expansion board does not provide enough power to drive USB devices like a Wifi dongle.

My plan was to take my Pi and E-Blocks to a Raspberry Pi meeting and access via my iPad, but when powered though the EB380 expansion board there is not enough power to drive the Wi-fi dongle, well not enough for my iPad to see the Wifi Network when next to iPad, The blue led on on the Wifi dongle lights but the Network is not seen.

My Ad-Hoc wifi network works on the Pi when its powered directly and the expansion Board is not plugged in.

Unless you can suggest a solution and given I am under 30 days I will have to return the expansion board as it does not meet my requirements. Note having to invest and use a power USB hub would be an inelligant solution that I don't want to pursue,

Hello Keith,

What voltage have you got the Matrix power supply set to? I would try the 7.5V setting and see if this works, otherwise use the 9V setting.

The lower the voltage from the PSU the more current will be allowed via the on-board regulator to drive your WIFI module.

The matrix supply is is set to 7.5volts as per the instructions.

Just tried 9 volts and SUCCESS!!!! Thanks very much

I will dig out my meter and check the 7.5 volt setting