NXT Power Functions Remote Control Sensor

Fun Projects for your LEGO^® MINDSTORMS^® NXT!

Power Functions Remote Control Sensor

Here is a way to make your own Power Functions Remote Control Sensor for the NXT using only snap-together LEGO parts. You can use the wireless Power Functions remote control to transmit the up/down/center position of the controls on the remote to the NXT, where you can respond to them however you want in an NXT program.

Important: This solution requires several electrical LEGO parts not included in the LEGO MINDSTORMS NXT set (see below), and it also requires the Education version of the NXT programming software or the Legacy Block Library (available here) added to the retail version of the NXT software.

LEGO MINDSTORMS NXT Power Functions Remote Control Sensor

Below is a picture of the complete solution for a two-sensor control (red and blue controls on one channel). The Power Functions Battery Box powers the Power Functions IR Receiver and two Power Functions M-Motors, which are connected to two RCX-style rotation sensors, which are then connected to the NXT via RCX-to-NXT adapter wires. A program on the NXT watches the two rotation sensors to see which direction they are turning (if any), which is determined by the position on the controls on the Power Functions IR Remote Control.

Optional gear attachments on the rotations sensors add friction to the motors to make them respond faster to the controls by preventing them from gradually coasting down when not powered.

Note that you could extend this solution to add another channel (for a total of 4 controls) if you used all four of the NXT sensor inputs and added more copies of all the parts (except the battery box), or you could also reduce it to just one sensor (red or blue) with fewer parts.

Here is a close-up picture of the optional gear attachment on the rotation sensor. The blue friction peg connected to the small gear adds friction to the rotation sensor to make it stop faster when not powered. This makes the controls respond faster to changes in position.

Electrical Parts Needed

A number of special LEGO electrical parts are needed for this solution, so unfortunately it is not inexpensive unless you already have the parts. You need:

Power Functions Battery Box
Power Functions IR Receiver
Two Power Functions M-Motors
Power Functions IR Remote Control
Two RCX-style rotation (angle) sensors
Two RCX-to-NXT Conversion Cables (included in the Education version of the NXT set)

Other LEGO parts Used in this Solution:

Programming the Response on the NXT

The PF_Remote program shows an example of how to respond to the remote control solution shown here on the NXT. It scans the RCX-style rotations sensors and draws arrow graphics on the NXT screen to indicate the position of the controls on the remote control.

The Education Version of the NXT-G programming software or the Legacy Block Library add-on is required because of the use of the RCX-style sensors.

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