Small BT board

Hi everyone ! I built my own drone and now I'd like to add a system that enables it to land or takeoff automatically (when you press a button), by using an Ultra Sonic range measurement sensor. I needed to know what is the smallest BT board supporting the arduino environment. Thank you.

I dont think there is a single board that does this.

You'd probably need something like a pro-mini, paired with a BLE module like a HM10.

BTW. In my experience the cheap ultrasonic modules are useless for drones as the sound / air flow from the rotors disturbs the air too much.

You'd one of those expensive large ultrasonic modules (see DIYDrones they have plenty of info on this)

I think there are unofficial boards that can be programmed with the Arduino IDE made for use in drones (optimized for weight, etc). You should look into those.

'328P or 1284P?

Or perhaps more to the point, you have built your own drone, which must therefore already have a Multi-Wii or similar controller, so why would you not simply add to that?

It must already have an interface that you would expect to connect to, so what are the details of the controller you already have and what interfaces does it have?

Actually I bult it by following the instructions on My flight controlle is an OpenPilot CC3D.

What about using a Blend micro (with bluetooth integrated) and activating the landing/takeoff by bluetooth ?(the range would be small but it's not a problem) Then the data would be sent to the flight controller...