CS 154 Homework #4
Due Monday, Feb 21, 2005

Readings for HW 4:

Robot Evidence Grids (pp. 1-16) by Martin C. Martin and Hans Moravec, CMU RI TR 96-06, 1996. (pdf is reversed)
Robots, After All by Hans Moravec, Communications of the ACM 46(10) October 2003, pp. 90-97. (pdf)

• Software setup     (0 points but much less aggravation!)    
  
  As some of you have noticed, the drivers for the Evolution and its sensors do not always auto-detect. The easiest way to handle this is to simply copy the device driver CD to a directory, e.g., C:\ERSP_CD on your hard drive. Then, when it asks for drivers, do not insert the CD! Instead tell the system you want to specify the location from which to load drivers, go into the ERSP_CD folder and point to the appropriate directory (Camera XP for the camera, the robot base directory for the base).


• Remote control client     (10 points)    
  
  Download the keyboard-control python program from the Software Page. This simple program just allows you to get keypresses without hitting enter. From this (and the simpleclient python client), build a remote-control client that allows you to drive around the ER1 from the keyboard. The idea is that we will (next week) be implementing a wandering behavior, and this client will make it easy to get the ER1 into the halls (and rescue it from situations in which it gets stuck!) Your client should offer one-press access to the odometry readings and infrared readings, as well.

  One important requirement of this remote-control client is that you make the space-bar a "stop" command... . You never know when you'll have to stop immediately!



• Seeing Red     (20 points)    
  
  Download the vision software from the Software Page and unzip it into the location indicated (your "drivers" directory). Note that this does not have to be done on the robot itself this week, since the vision won't be used to control the robot (yet).

  Try out the software with the ER1's USB camera (feel free to unattach the camera and plug it into the USB port on the computer). In particular, this file (visionNotes) has a brief explanation of most of the features of the Vision tool.

  Your task is to implement the two functions RGBtoHSV and processRed, so that the tool demonstrates (1) what pixels it thinks are red, (2) whether or not the camera is currently facing a red molding (through the center of the image), and (3) an estimate of the location/slope of the red molding in the image. You may write RGBtoHSV based on our class coverage of it, or simply go online to find one of the many available implementations. However, be sure you know the ranges of the hue, saturation, and value (intensity) bands.

  Your program should highight those pixels it thinks are red in a distinctive color, it should indicate graphically when it sees a red molding (for example, have something appear or change color), and it should draw the line at which it estimates the molding's position, when present. Each part is worth 7 points. (Everyone gets the extra point...) A suggestion for making your code easier to tune is to use key presses to change your RGB/HSV parameters on the fly. You will definitely NOT want to recompile everytime you want to change your definition of "red."



• Sonar!     (20 points)    
  
  For this part of the assignment, you will need to create a couple more connectors in order to solder and connect one of the Devantech SRF-04 sonar range finders to the servomotor controller.

  The servo motor creation page provides the details you'll need to create the connectors and circuit for the sonar.



• Updating your project webpage     You should add the following things to your project webpage -- this is where I'll go to evaluate how things progressed:
  
  • references to this week's papers, integrated into your project introduction
  • a link to your remote-control client, and any additional comments you might have about how it works or what it does
  • a link to your VideoTool.cpp source code and screenshots of how well your red-molding finding went
  • a bit of description and a few images on how your sonar-creation went
  
  Of course, please let me know if things don't seem to be working out, and we'll resolve whatever it is together!