Posts: 128
Joined: Fri Dec 28, 2012 9:49 am

RC Helicopter

Sat Feb 09, 2013 3:15 pm


I would like to start preparing for a new project where I will fly a remote control helicopter with my PC keyboard. To begin with, I am going to try to get the helicopters collective pitch (the main rotor blade - upward and downward control) working by using the up arrow and down arrow keys.

After long research, I have disovered that the best way to do this is to have my program say: if the up arrow key is pressed, send an infrared signal of x frequency. I gathered that to do this I would need an infrared emitter.

The fundamentals are, I need to know how to program a infrared emitter using Python. How do you send different frequency infrared from an IR emitter?

Many thanks in advance,

Posts: 23
Joined: Thu Dec 06, 2012 10:39 pm

Re: RC Helicopter

Sun Feb 10, 2013 2:11 am

IR is a red herring. It would be a bit of an odd approach to a helicopter, because infra red is very much line of sight. You need to look at radio controls. Forget about blinking an IR LED.

I have been thinking about hacking a RC car remote, and I think this might be the best approach for what you want to do too. Hack an off the shelf helicopter remote.

I am thinking that a helicopter control for motor rotation is possibly a simple potentiometer. If so, you could find the three contacts, and solder your own wires to them. One to the plus side, one to ground, and one to the middle signal. But even then, we have a bit of a problem. The RPi is a 3v3 digital machine. It would be relatively easy to output a number from the keyboard that could be converted to a voltage between 0 and 3v3, but I think you will have to up the voltage to reach what the remote is excepting.

The idea is to create a software driven variable resistor to replace the one on the remote.

I will have to think about it, and I am probably over thinking it, but stop looking at Infra red. Radio frequency is what you need.

User avatar
Posts: 2156
Joined: Fri Aug 05, 2011 4:30 pm
Location: Susanville CA.
Contact: Website

Re: RC Helicopter

Sun Feb 10, 2013 5:13 am

There are a lot of the small coaxial helicopters that use infra-red controllers. They are meant for indoor use only. These copters do not have collective pitch. They use changes in motor RPM (a seperate motor for each rotor) to rise (ascend), lower (descend), rotate left (yaw left), rotate right(yaw right). They have a small horizontal tail motor/prop for pitch (forward/reverse flight). There is no roll control.

In fact one of these would be a perfect first project for remote control. The only caviat is that they are definintely LOS (Line Of Sight). But the copter itself would not have to modified to be controlled. These coaxial helicopters with gyros are very, very stable.
I would reccomend the "SYMA 107G" ($20 to $30)
or if you want it with a camera get the "SYMA 107C" ($35 to $50). The camera is the black box between the skids.

Both are pretty quiet and fly around the house terrorizing dogs and cats (watch out mooncake).

Collective pitch copters are constantly having to be FLOWN. They need almost constant small corrections to maintain altitude and attitude. It can be done but you would have to build in telemetry to keep it where you want it. Even if you incorporated a flight control board,

http://www.hobbyking.com/hobbyking/stor ... O_ACC.html
they may not be as stable as that cheap little coax copter. They are also much more expensive.

order of ease in flight;
Coaxial rotors with a gyro (infrared and radio)
Coaxial rotors without a gyro (infrared and radio)
Fixed pitch rotors (radio)
Fixed pitch rotors with three axis gyro and accelerometers (Radio)
Multirotor (quadcopters all have a flight control board with at least gyros)(infrared and radio)
Collective pitch with 3 axis gyro.(radio)
Collective pitch rotors with single gyro ((heading hold) one gyro for tail rotor)(radio)

I have not delved into python yet, guess I am lazy, but that is where I would look for a start. Start with a heli that pretty much flies itself and then work on more complicated projects after you get that licked and working!
512MB version 2.0 as WordPress Server
Motorola Lapdock with Pi2B
Modded Rev 1.0 with pin headers at USB

(RS)Allied ships old stock to reward its Customers for long wait!

Return to “Automation, sensing and robotics”

Who is online

Users browsing this forum: No registered users and 24 guests