USB-UIRT Forum

Has anyone tried controlling one of those $29.95 IR controlled helicopters with this thing?

I got some pronto codes from the controller, it's transmitting at 38.9 KHz and it seems pretty consistent, so should be reproducible. The controller transmits codes for a few seconds when turned on, then waits until one of the sticks is moved. It's basically a two channel radio, rotor speed and tail rotor speed, you move forward by very slightly rotating the tail in one direction, and reverse by doing the opposite. When you get good enough, you can actually go in a straight line, but that takes some practice. If the controller is not transmitting, the helicopter shuts off (and usually falls to the ground).

Some pronto codes, acquired using UIRTLearnIR:

Rotor speed at full:
0000 006D 0000 000C 0078 0014 003C 0014 003C 0014 003C 0014 001E 0014 003C 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 003C 0D62

Rotor speed at lowest position (just above stop):
0000 006C 0000 000C 0078 0014 001E 0014 001E 0014 001E 0014 001E 0014 003C 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 003C 0D62

Rotor off, full right:
0000 006C 0000 000C 0078 0014 001E 0014 003C 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 001E 0014 003C 0D69

Rotor off, full left:
0000 006D 0000 000C 0078 0014 001E 0014 003C 0014 001E 0014 001E 0014 001E 0014 003C 0014 003C 0014 001E 0014 001E 0014 001E 0014 003C 0E35


There are (rather large..) steps in between and a tail rotor trim adjustment, but they're very difficult to read using UIRTLearnIR. I think the trim just adjusts the "neutral" position for the tail rotor, then the stick changes the value relatively.

Is there any way to get raw codes in the IR receive callback? That'd make this much easier to figure out...

It would also be handy to be able to visualize as a waveform. Hrm... I bet I could write something do that.

I managed to get it to shoot off my desk like a rocket (main rotor at full tilt... weeee!)

It seems once you send it a code, it'll run for 2-3 seconds. At least for the main rotor, I haven't tried changing the tail rotor speed to see if it's more responsive (a little more work to get that done..). And the controller seems to send a "stop" command when both sticks go neutral.

Hi -
have any one try to write a C++ code that can control the main rotor speed of the helicopter? This will be an interesting control project. If any one has an idea on how to write a C or C++ or Matlab code to communicate with USB-UIRT I guess the helicopter can be controlled. I appreciate any feedback.

SA