gersbrett
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Joined: Wed Feb 26, 2014 11:58 am

Connect to SD Card

Wed Feb 26, 2014 2:00 pm

I want to use the Pi to “snoop” on an SD Card that is inserted into another device (dev1). I did some research on the net and so far I have not found any nice solution to do so:

Dev1 has an SD card inserted and is writing from time to time (exactly every minute) small text files onto the card. The RPI needs to read those textfiles and do something with them (e.g. send via ethernet).

The only idea that I came up so far was to use an SD-card extension cord, split it up and connect one side to an usb-card reader so that both devices are connected to the sd card simultaneously. Then I somehow would have to be able to tell when dev1 is not writing (which could be done via GPIO) and read from the card. However, I am not sure if that even could work so simple as the devices might interfere with each other. I could use some relays (from an extension board) to disconnect the card detection lines. However, this whole concept seems to be a little bit fragile.

Does anybody have an idea to solve this a better way?

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Burngate
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Re: Connect to SD Card

Wed Feb 26, 2014 5:36 pm

What is "dev1"?

If you tried connecting two devices to the same card, without some quite sophisticated software, I would expect either the card will quickly get corrupted, or both devices would get confused, or both.
However, depending on what "dev1" is, maybe you could connect them via a network, and use samba to transfer the information.

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richiepp
Posts: 140
Joined: Wed Dec 19, 2012 4:56 pm

Re: Connect to SD Card

Wed Feb 26, 2014 6:42 pm

I've had this same question with a Raspberry Pi connected to Arduino with SD card via usb. I'd like to record data on the SD card as a text file and read it from the Pi. Can this be done with serial?

Thanks
Rich

gersbrett
Posts: 2
Joined: Wed Feb 26, 2014 11:58 am

Re: Connect to SD Card

Thu Feb 27, 2014 7:40 am

Unfortunately I do not know a lot about the logic composition of dev1, it is a logger that logs some data (temperatures etc.) on the SD card. The only interface on it, is the SD-card slot.

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Burngate
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Location: Berkshire UK Tralfamadore
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Re: Connect to SD Card

Thu Feb 27, 2014 10:50 am

gersbrett wrote:The only interface on it, is the SD-card slot.
Hmm ... that's a bummer
If it were me, I'd be taking the lid off to see if there's anything inside I could hijack ... but I wouldn't be surprised to see not much more than one big chip.

Sorry, can't help.

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