Having issue with navigation program

Hello group,

I am trying to run the boe bot using the led sensors (chap 7 of boe bot manual). The program I am trying to run is the same as "navigating with whiskers" but is using the sensors instead. When I have the boe bot stationary and just test the sensors they work fine. When I try to incorporate the navigation program the boe bot does not behave as planned. When it is going forward and senses an "obstruction" it will back up but not turn and then try to move forward again basically putting it in an endless loop of "forward and backward". I have double checked my program and it is legit (word for word compared to the manual). I also had this problem when I tried running the "navigation with whiskers program" but figured it was something I was programming incorrectly. Has anyone had this type of issue before and if so what was the fix? Thank you in advance for your time.


  • Can you attach your program listing. Maybe we could check it for errors
  • Is this it
  • I will post my program as soon as I get home this evening for review. For some reason I am not able to view the program that you posted but if it is the "navigating with whiskers" that uses the sensors instead of whiskers then yes it is the same.
  • Are you using IR sensors? A Parallax part? A picture of your setup would help troubleshooting.
  • I will post pics of my setup as well as the program as soon as I get home. Thank you all in advance for the input and assistance!
  • When you click on the bs2 program in my posting it should open your pbasic tokenizer
  • Here is my program and pics of the connections. This is regarding the program on page 238 of the boe bot manual and I am using the board of education board.
    5184 x 3888 - 5M
    5184 x 3888 - 5M
    5184 x 3888 - 4M
    5184 x 3888 - 4M
  • The first thing I see in the photos is that the IR emitters are being blocked by the receivers. Try putting the receivers, (long black units), horizontal to the table.
  • I put the receivers horizontal with respect to the table and I am still having the issue, without sensing the motors driving the servos operate fine (operate programs as intended). There just seems to be some sort of mismatch when sensing...
  • Try this one, I've added some debug statements so you can see if your sensors are working. Check connections and make sure your in the right pins. Check for dead pins you might want to reassign the pin numbers and move the sensors to the new pins.
  • Now that I've look at your pictures more closely you don't have anything plugged into Pins 5 and Pin 7, these are your pins you've assigned to your sensors. Looks like your using Pins 0,1,4,8,9, and 10. Plus the servo jacks 12 and 13.
  • The problem is your program is wired for the whiskers config. Pin 5 and 7. The IR phototransistors are wired different. go to the code in the chapter for light sensors and practiced that one.
  • Thanks! I will check it out and see where I went off the rails with the program!
  • These resistors look like they're touching, too. That's certain to cause erratic behavior.

    This is one of those projects that requires a lot of attention to detail. Test the subsystems, just like we show you in the book.

    Ken Gracey
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