I've been doing some pretty rigorous testing over the last few days trying to get the USB adapter to interface with the Bluetooth adapter. No matter what I do, I can't get the two to interface. At first I thought this might be a power issue, and so I added a powered USB hub to see if that would help. No luck. Next I tried hard wiring the power bank that I intend to use for the built in QI charger. This time both the USB Keyboard Adapter and the Bluetooth adapter were powered up and obviously responding, but they still weren't talking to one another. Having tried the combination on a variety of different platforms (iPhone, iPad, MacBook, PC, Raspberry Pi) and still having no luck, I admitted defeat. Bluetooth just isn't going to be an option for now. I don't know why, and if anyone has an ideas I'd be interested to hear them!

So, what to do next? I decided to purchase an unofficial Lightning to USB Camera Adapter from Amazon for about £12 in order to connect the USB Keyboard Adapter directly to the iPhone. Thanks to Amazon's same day delivery it was in my hands that evening. I hurriedly connected it all up, plugged it into the iPhone and..............it didn't work. I got an error message on the iPhone saying that the Arduino needed too much power. So, out came the powered USB hub again! This time it worked. This is a long known work around for the power issue on the iPhone and iPad. The only issue being the size of my USB hub. Some redesign would be needed. But, at least I could finally type on the iPhone using the Psion keyboard. It would just need some refinement.