USB to Arduino to bluetooth

Question

I have a piece of equipment that has a USB output, that a flash drive gets inserted into, to collect data as the equipment completes its cycles. I need to make a device that can replace the Flash Drive and take the data from the USB port and either save onto an SD Card, to re transmit when completed, or to transmit live as the cycles complete. I was thinking about using a UNO, & a USB HOST Shield. to receive the data. Then transmit with a wireless or Bluetooth shield. I have a "SANDISK WIRELSS FLASH DRIVE" which works as a flashdrive, and then you can connect it to other devices through wireless transmission, problem with it is, the wireless feature disables when plugged into the usb port. If the wireless stayed connected, then this would be exactly what I needed.
Any help or ideas, sample schematics would be welcomed.

Answer 1

There once was once something called an "Infinite USB Memory Drive" that acted as a thumb drive that read and wrote data to a networked share over wifi.

They aren't selling those anymore, but their approach might be what you need - network share to resolve the issue of multi- device connected to same drive.

In your shoes, I'd be looking at a Raspberry Pi Zero W (the one with wireless) instead of an arduino. More computing options means more ways to solve your problems with the same hardware.

Answer 2

Your plan is flawed.

First, you don't want a USB host - a flash drive is a device, not a host. This unspecified unit that you are connecting to is the host.

Secondly you would require an Arduino a lot more complex than an Uno. You need one that is capable of operating as a USB MSD (Mass Storage Device), and the Uno or any other '328p-based device cannot do that.

The only two kinds of Arduino-like board that I know of that can do that are Teensy and chipKIT.

On top of that is a simple fact that is the reason your existing wireless flash drive doesn't work for you: only one thing can access a "block device" at once. If you had the USB and the wireless both accessing the flash drive at once you would get massive data and filesystem corruption - so it is just disabled. You need to have some manual way of switching off one point of access and switching on the other - and of course safely "unmounting" the device to ensure that all cached data is written to the disk properly.