May 03, 2013: This project finally comes to an end, so I recorded two demo videos to show the robot following me, outdoors. A few modifications in software are likely to be done, but all in one, the work is pretty much complete:

Demo 1:

Demo 2:

May 22, 2013: As I am a perfectionist with all that I build, I couldn't stay away and had to make this robot even better. So I did two things:

1) For the autonomous, human following software: I improved the ultrasonic detection algorithm, and the movement logic: Now the robot will follow its user more precisely, and the speed will vary with the detected signal: if the robots sees the user at a greater distance, will engage with a greater speed. If closer to the user, will proceed with smaller steps. The calculations are not linear, so I used some time to get the best formula. In the end I'm quite pleased, we can see some nice improvements when compared to previous two videos - so here are two new demos:
Demo 3:

Demo 4:

2) For the remote control software, where the user controls the robot using a phone, the rover now reports its frontal sensor readings (that show the proximity in centimeters to any detected obstacle), to the smartphone. So the movement commands go from phone to robot, and the sensor readings go the opposite way, from robot to phone. The Android software now allows the user to turn the lights on and off, and using the frontal distance sensor, a red line is drawn, showing the proximity to an obstacle. The robot can be controlled this way - without actually seeing what it is heading for, as this simple radar will be enough to get a clear path. Here is another demo:

3) When bluetooth is connected, the robot will ignore any ultrasonic signals from its beacon. So better separates the two modes of operation discussed above.

Resources:

Mechanisms for Combining Infrared and Ultrasound Signals for Indoor Wireless localization
Infrared / Ultrasonic beacon
Ultrasonic Source Localization
Mobile Robot Navigation
Learn about GPS

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