Just to add to this thread, the Boox remote control can be somewhat expensive. I've seen it for $35 plus another $30 for shipping/customs charges, so if you don't need the full integration that it offers, and just want a cheap page turn device... that you can use on other devices.. the selfie remotes you can pick up for a handful of dollars on the usual auction sites from China work just fine.
I have this one.. (in blue)
The Chinese packaging says its a G1, the Bluetooth binding says it is a BLE-M3 keyboard. You'll need to enable the internal on screen keyboard at the same time when you use this, as Android thinks that the button clicker is also a fully capable keyboard and expects all input from it.
In NeoReader 3.0 the shutter button does next page, and the back/up arrows go back a page. the foward/right arrows do next page. Sometimes it does lose its way with the arrow buttons, it's not perfect in that respect. I daresay you could use a keyboard mapping program if that irritated you.
And, you can also use it with your normal phone or tablet to take selfie photos as it was designed! Tested on my Note2, it should work on any other Onyx device.