Goofy Giggles IR Signal Decoding

Overview

The Goofy Giggles robot comes equipt with an infrared (IR) transmitter puck and an integrated receiver pod. The IR transmitter puck is designed with three large buttons to allow a child to control goofy giggles. The buttons cause the original toy to move forward, rotate, or play sounds.

IR Transmitter: The IR transmitter puck has three buttons that each send a unique button depressed message. A common button released message is sent when a button is released. Two of the buttons have the capability of auto-repeating the depressed message. One of the buttons issues the button released message automatically after the button depressed message regardless of actual state of the button.

IR Receiver: The IR receiver is located in the orange globe above Goofy. The receiver faces up into a conical mirror. This mirror gives the receiver 360 deg visibilty. Because Goofy was originally designed for young children, this feature is essential as the child will likely not point the transmitter directly at the robot.

The receiver's digital output is connected to the P4.0 input on the MSP430F169. This pin allows you to either poll the signal or use the timer capture capability of the MSP Timer B to decode the signal.

IR Data Message Bytes

GG IR Message Summary

	Data Byte	Auto Repeat	Auto Released Message
Forward	0xA1	YES	NO
Rotate	0xC1	YES	NO
Play Music	0xB1	NO	YES
Button Released	0xD1	NA	NA

Scope Traces

• Full Byte
• Start Marker
• Data Bits
• Temporal Properties of the IR signal
  • Play Music Button
  • Forward Button Auto-Repeat
  • Quick Press of Forward Button
  • Scope trace showing the 38khz modulation of the IR LED measured at the TX
  • Scope trace showing the phase shift of the IR receiver on Goofy

[Return to H335 Lab Tools]