lsmod
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SD card emulator

Thu Feb 11, 2016 2:28 pm

Hello,

i am searching for a solution to grab the files that are written to a SD-card from a camera.
Up to now i only found solutions to interface to an SD-card and not to emulate an SD-card!

I could find an document that someone did this job with an microcontroller
http://www.thinkmind.org/download.php?a ... 4_30_10048
but i think this should be possible with an Raspberry too.

Here is a solution to interface to an SD-card, but i want to do the inverse:
http://blogsmayan.blogspot.de/p/interfa ... -card.html

I am suprised that my idea is somehow new.
Has anyone seen a solution / implementation for this problem?

DirkS
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Re: SD card emulator

Thu Feb 11, 2016 3:54 pm

i am searching for a solution to grab the files that are written to a SD-card from a camera.
Can you clarify this? I cannot see how the emulator bit comes into this.
It just reads as 'there are images on an SD card and I need to grab these'.
So my first reaction: use an SD card reader and simply copy the files...

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Laurens-wuyts
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Re: SD card emulator

Thu Feb 11, 2016 4:36 pm

I think the OP means something that you put in a camera as SD card and directly saves the images on the pi.
So the camera thinks there is an SD card inserted, which is the pi.

I think this is possible, because an SD card is some sort of SPI AFAIK.

Laurens

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chrisoh
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Re: SD card emulator

Thu Feb 11, 2016 4:43 pm

You can get SD card adapaters with built in WiFi, could access the photos that way I imagine, I've never tried one though.
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lsmod
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Re: SD card emulator

Thu Feb 11, 2016 5:27 pm

Laurens-wuyts wrote:I think the OP means something that you put in a camera as SD card and directly saves the images on the pi.
So the camera thinks there is an SD card inserted, which is the pi.

I think this is possible, because an SD card is some sort of SPI AFAIK.

Laurens
Correct. I will not use an SD-card and get the data direct to use it.

The problem is you only get webcams with lower quality then a cheap digital camera.
At this time i am using a Logitech HD720p.
It's a better model with adjustable focus.
But the picture results are not convincing and the camera does not work stable any more after a half year. :(

So i want to build a perfect and cheap solution.
I have here an old but new 2 Megapixel camera from Polaroid.
I will modify it and connect all needed contacts to the Pi.

Now i am searching for a good method to get the pictures.
I could not believe that there is no ready software to emulate an SD-Card.

lsmod
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Re: SD card emulator

Thu Feb 11, 2016 5:30 pm

chrisoh wrote:You can get SD card adapaters with built in WiFi, could access the photos that way I imagine, I've never tried one though.
No - this solution has many disadvantages:
1. Such cards are not cheap.
2. I have read that this cards are not working reliable.
3. The way over WIFI is to inconvenient.

Then i better connect the Pi parallel to the SPI bus of an inserted SD-Card and read the picture after it is taken.

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chrisoh
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Re: SD card emulator

Thu Feb 11, 2016 6:17 pm

It has many adavantages too, swings and roundabouts ;)
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lsmod
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Re: SD card emulator

Thu Feb 11, 2016 6:19 pm

Only when you can say: I have tested it and it works! ;)

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chrisoh
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Re: SD card emulator

Thu Feb 11, 2016 6:32 pm

The existance and prevalence of the product means it does work :roll:
Evidently not the solution you're after, good luck with your emulation.
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lsmod
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Re: SD card emulator

Thu Feb 11, 2016 6:43 pm

chrisoh wrote:The existance and prevalence of the product means it does work :roll:
Then you have never used chinese products. :mrgreen:
They are defined as "working" when it is doing "something".

Maybe i will go deeper into my idea of this emulation.
It is a good general solution to use cameras for automated "high end" pictures.

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Laurens-wuyts
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Re: SD card emulator

Thu Feb 11, 2016 6:47 pm

Well I like the idea ;)
I think it's possible to do, but it will take a while to finish. :)
If you have further questions, I'm glad to anserw :P

Laurens

lsmod
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Re: SD card emulator

Fri Feb 12, 2016 9:10 am

At least there are two problems:

1. It is much work to get such an emulator to fly.

2. The main product where you need it are cameras, because they inhibit to get automated full quality pictures.
Most of the other products offer an additional interface to get the data.

Rnd(100)
Posts: 9
Joined: Mon Feb 08, 2016 9:19 pm

Re: SD card emulator

Sat Feb 13, 2016 10:53 pm

lsmod wrote:Hello,

i am searching for a solution to grab the files that are written to a SD-card from a camera.
Up to now i only found solutions to interface to an SD-card and not to emulate an SD-card!

I could find an document that someone did this job with an microcontroller
http://www.thinkmind.org/download.php?a ... 4_30_10048
but i think this should be possible with an Raspberry too.

Here is a solution to interface to an SD-card, but i want to do the inverse:
http://blogsmayan.blogspot.de/p/interfa ... -card.html

I am suprised that my idea is somehow new.
Has anyone seen a solution / implementation for this problem?
Hi,

This was something that I was interested in some time ago, this link might be of interest :

http://webpages.uncc.edu/~jmconrad/ECGR ... ROLLER.pdf

Is this the sort of thing you had in mind ?

lsmod
Posts: 13
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Location: Germany

Re: SD card emulator

Sun Feb 14, 2016 10:01 am

Rnd(100) wrote:Is this the sort of thing you had in mind ?
This is it nearly - thanks for the Link.
In this project data is supplied as bmp picture on an emulated sdcard.
So it would be enough to implement only instructions for reading.

But it shows that there are already similiar ideas and implementations out there.
For this project no sources are published.
Do you have more informations for this project?

FredTheFret
Posts: 24
Joined: Wed Apr 15, 2015 2:47 pm

Re: SD card emulator

Mon Feb 15, 2016 2:04 pm

You really should search for an alternative. SD-card emulation is NOT a trivial task.

I've spent some time looking into this for my own reasons and found perhaps FPGA devices may be up to the task, to convert SD-card signals to something else. I do not have experience with FPGA myself, they can be quite expensive devices etc. And even if you'd be able to get every bit of data that is 'written to the SD-card' you'll have several problems. Some are in fact SD-card control/initialization messages. Another is that the 'write data' isn't just the data for the files you expect. There's file-format shit written to the drive and whatnot.

lsmod
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Location: Germany

Re: SD card emulator

Thu Feb 18, 2016 10:24 am

Yes - that's the reason why it is a better solution to insert a normal SD card and then read the files after they have been written.
For reading SD cards there are many solutions out there.

Rnd(100)
Posts: 9
Joined: Mon Feb 08, 2016 9:19 pm

Re: SD card emulator

Sat Feb 20, 2016 10:05 pm

lsmod wrote:This is it nearly - thanks for the Link.......
........Do you have more informations for this project?
Have a look at :

ftp://ftp.circuitcellar.com/pub/Circuit ... ne-209.zip

http://www.docin.com/p-343749173.html

motorbikematt
Posts: 1
Joined: Thu Aug 11, 2016 2:31 am

Re: SD card emulator

Thu Aug 11, 2016 2:39 am

@Ismod...Any luck with this project? I'm looking for nearly the exact same thing and am so glad I finally found this thread!

tink
Posts: 2
Joined: Wed Oct 05, 2016 9:53 pm

Re: SD card emulator

Wed Oct 05, 2016 10:00 pm

Hi, has there been any news on this topic?


Also, would you use the SPI [slave] for communicating, or something else?


Finally, if no Raspberry Pi would be enough *but* it's SPI, then what about using the Teensy 3.5 device, its CPU description at https://cache.nxp.com/files/microcontro ... 120SF5.pdf says it can do SPI in slave mode (page 56+).

Any more pointers on how to make this real?


Up to now I guess the most useful references I saw were your http://webpages.uncc.edu/~jmconrad/ECGR ... ROLLER.pdf / ftp://ftp.circuitcellar.com/pub/Circuit ... ne-209.zip reference.

That one indeed uses SPI.


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