And list what models you tried. As to 30 or 40 feet that's beyond all wireless keyboards you find in stores. Even BlueTooth is iffy past 15 feet from my experience.
Let me be clear. No off the shelf at the usual stores will solve this wirelessly.
Ask if you can use some Android or iPad to do this over WiFi.
How can I use a keyboard/mouse with a Samsung Smart TV model UN40ES6150. It doesn't appear to recognize any wireless. A call to tech support said that it should recognize any usb keyboard (it doesn't) or any hdmi keyboard... ??? Didn't know they existed and I don't know what to look for. Are there any suggestions? Also, this TV is on a wall, how would I get any type of keyboard to work with this that would allow me to sit on the couch while the TV is on the wall... do they make anything with a 30-40 foot cable even on it?? I'm at a loss on how to use this....