Hi Guys,
I am doing an electrical project for college which involves an RC helicopter. I've been asked to implement a control loop to get it to hover at a set height with movement commands coming from the handheld controller. All that is autonomous is the height it should be flying at. I've been looking at ways to measure distance from the heli to the ground, but have not been very successful. The majority of cheap ultrasonic sensors are AC input and so I would need to somehow convert my DC supply to AC, which is a bit impractical. Also from looking at other discussions about accelerometers being used seems to suggest accuracy will be awful. Does anyone have any suggestions for a device that will be able to convert the distance from the heli to the ground into an electrical signal that i can feed into my control loop?

What will be the maximum altitude of the helicopter? I have used a distance sensor like this before. They are very easy to use.

Originally Posted by vne147

What will be the maximum altitude of the helicopter? I have used a distance sensor like this before. They are very easy to use.

Hi, we are going to be using these over about a 1m range so looks ideal.

I also found this one at the same site. It senses distance between 0 - 6.5m The first IR based sensor that I linked consumes about 33 mA but this one only uses about 2 mA. I'm not sure what kind of helicopter you are going to use but if it's one of those cheap foam ones, the current draw might make a significant difference. Good luck!