Trying to send commands via USB Host Shield to a medical device.

I bought a USB Host shield off sparkfun and an arduino Uno R3. Put the shield on top of the Arduino, soldered every pin, and now am having trouble getting it to communicate with a medical device I need to send commands to.

The device itself is very simple, with only a few 'low level commands' like RF ON or RF OFF.

I read about this and people are saying I have to literally create a driver for the device? Does it help that I don't need to receive commands, just simply push them?

I'm very new to this whole thing so I apologize if I'm missing something drastic and sound like an idiot. I've been through the github on Oleg's Circuits@Home project but can't find anything that seems to relate to my issue. They only deal with usb controllers or cameras. Not how to create a driver or interact with an arbitrary usb device.

For each device/circuit, you'll need to create what your commands are and how they work, so to an extent, yes you need to write a driver. I am unsure what the Host shield is doing in this so perhaps you should explain in more detail what you need to do.

The device itself is very simple, with only a few 'low level commands' like RF ON or RF OFF.

Writing a USB host driver is not easy. Perhaps you don't need to.

I suggest you plug the device into a PC and see what USB devices it presents. Perhaps it just looks like a simple serial port, in which case you may be able to use an existing host driver. If it does need a bespoke driver then you would probably need information from the vendor to create one. If they're willing to support 3rd party development then there may already be suitable drivers available - although probably not for the Arduino platform. If they aren't, then writing your own USB host driver will be much harder, perhaps impossible. Also review your decision to use an Arduino as the host - this sort of thing would probably be much easier on a computer such as an RPi, or a tablet or laptop.

I plugged it into the computer, it beeped, installed drivers, and that was that. In device manager its called a USB Serial port with

How else can I obtain more details about this device using my laptop?

Thanks so much for your help.

That's lucky, because a virtual serial port is probably going to be one of the easiest host drivers to find/write, and because you won't have to rely on the OEM to give you details of their USB protocol. You may even find that there are some examples for the shield that show how to host a virtual serial port.

The engineer who made the device I'm interfacing with said its FTDI interface. Any ideas how to interact with that?