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[on:]

Wondering if this is possible. The main limitation is the file says, lets say on average 8mb. From what I can see so far, the XBEE type TX/RX won't work because of data rates. If I found the right numbers, it looks like using those type of methods would take 4 minutes to transfer. This leads me to believe that a WIFI protocol has to be used. So essentially what I need to do is:

usb data out of device, into the Arduino that is battery powered. TX through WIFI (something else?) to RX small arduino. The RX arduino just needs to the data and put it into a USB port on a laptop lets say. So both ends look/feel/act like a USB cable was plugged in, but in between it's wireless.

I essentially want to do what these will do http://www.amazon.com/Cables-To-Go-29570-Wireless/dp/B001JEPC3G/ref=pd_sim_sbs_pc_4  except not all the extra hubs, and the "dongle" attaching to the device needs to be self powered (not powered through the USB connection).

Any thoughts on how to do this? Where to start? I tried searching around and can't find any real information.

Thanks,

Justin

[Reply #1 on:]

Suggest you start by reading up on the USB protocol and look at the examples for the USB host shield. Essentially, what you'd be doing is tunneling the USB protocol over a WiFi (or similar) link.

For a one-off you may be happy to ignore any issues to do with security and discovery and just shove the USB messages both ways over a hard-coded TCP connection over the Wifi link.

[Reply #2 on:]

Thanks for the reply. Not concerned about security.

If you have two wifi boards, can just the programming get them to link specifically to each other? Kind of like an AD HOC?

I guess part of the question is that: How do you get the data to tunnel through the wifi link? If you just connect the data terminals from the USB into the data part of the WIFI, will it just send it through the link?

I'm sort of weak on the programming aspect. I understand more of the hardware with the USB host board, WIFI board....if you put those things together, how then do you tunnel.

Thanks for the help! Any recommendations for links to read/study on this subject is greatly appreciated. I'm not against researching myself, I just can't find the info I'm looking for.

[Reply #3 on:]

Can a different wireless protocol be used? Or is WIFI the best for files that large?

RFID? Bluetooth? It's hard to find the exact data rates.

[Reply #4 on:]

Surprisingly, I have found that XBee is faster than the Wifly board specifically.  Perhaps because it is serial and can only transmit when each buffer is full. I can get roughly 12KB/sec over XBee, only half with Wifly.  Maybe another Wifi board is faster?

[Reply #5 on:]

uhhh geez, that's really slow for my needs. According the the WIFLY manual, it should get 1mb/s serial and 2 mb/s SPI. What am I missing?

Can you take a USB host board, and simply take the D+ and D- data ports and plug them into the wifi board's TX/RX?  Or am I missing something on how the data has to be moved between boards?

[Reply #6 on:]

What you are trying to do is not a trivial task.
You have to implement the entire USB 1.0 protocol (thats the best you can hope to achieve over wi fi) between the 2 ends
of the wi fi link.
Heres a link to the protocol spec.
http://www.usb.org/developers/devclass_docs/usbccs10.pdf

This might be of some help in implementing part of the USB spec.
http://www.obdev.at/products/vusb/index.html

Its not free though.

Most of the USB wireless extenders use custom VLSI chips to do all the hard work, which is one reason they are fairly pricey.

[Reply #7 on:]

Thank you for those links, good reads.

Does a USB host board not include the USB protocol? For example:

http://www.circuitsathome.com/arduino_usb_host_shield_projects 

Could I not take that, in HID or PTP classes, send the data through the WIFI card, RX that data back into a WIFI card, send the data to another USB board(can it be a host?) with the same class?

[Reply #8 on:]

Whats the "device" that ultimately providing the data.
Thats what you have to support at both ends.

[Reply #9 on:]

The device would be a camera. So I think that would be the PTP class.  I believe that can be loaded into the host shield like the one I posted.

Can anyone help with the hardware required? Can I use the host shield and a wifi shield of some sort and just funnel the data through those cards on the SPI protocol?

[Reply #10 on:]

@uavmx:

If the intent is simply to offload the contents of the camera SD card to a PC, maybe you can use something along this line: http://www.eye.fi/

The 4G cards are under $40 at WalMart, so not an unreasonable price in my book.

- Ray

[Reply #11 on:]

I'm familiar with eyefi cards. They don't have that great of range and can have flakey connecions. Not ideal for professional use.