Noob question..

Unsui

Hello All!

So I just got my Boe-Bot a few weeks ago and it's my first bot. I'm familiar with programming to an extent and I feel like I understand what's going on in my code but I'm vexed by a problem.

I've installed the whiskers and tested them, I've also written several successful programs for basic locomotion. But when I go to combine the two it refuses to work(at least correctly). I've disassemble and reassemble the circuits, rewritten the code. Followed the book to the letter. So here is the code:

' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Program Running!"

pulseCount VAR Byte

FREQOUT 4, 2000, 3000

'main
DO
IF (IN5 = 0) AND (IN7 = 0) THEN
GOSUB Back_Up
GOSUB Turn_Left
GOSUB Turn_Left
ELSEIF (IN5 = 0) THEN
GOSUB Back_Up
GOSUB Turn_Right
ELSEIF (IN7 = 0) THEN
GOSUB Back_Up
GOSUB Turn_Left
ELSE
GOSUB Forward_Pulse
ENDIF
LOOP

'subroutines

Forward_Pulse:
PULSOUT 13, 850
PULSOUT 12, 650
PAUSE 20
RETURN

Turn_Left:
FOR pulseCount = 0 TO 20
PULSOUT 13, 650
PULSOUT 12, 650
PAUSE 20
NEXT
RETURN

Turn_Right:
FOR pulseCount = 0 TO 20
PULSOUT 13, 850
PULSOUT 12, 850
PAUSE 20
NEXT
RETURN

Back_Up:
FOR pulseCount = 0 TO 40
PULSOUT 13, 650
PULSOUT 12, 850
PAUSE 20
NEXT
RETURN


Basically no matter what input registers the Back_Up subroutine doesn't run, and the IN7 causes a 180 degree left rotation and the IN5 a 90 degree rotation. I'm really excited to progress but I'm stumped right now and I don't know what I'm missing. Please HELP!

Thanks!

Mike Green

Your program looks like it sort of would work, enough that you'd be able to fine tune it. In any event, Back_Up should be called if both whisker switches are closed at the same time. Check your wiring again. Make sure the switches are connected to I/O pins 5 and 7. The switches should connect the I/O pin to ground when they're closed. You should have a pullup resistor between each I/O pin and +5V.

If the BoeBot isn't turning properly, re-center the servos. There's an adjustment you must make so that the wheels don't move if they're sent a pulse 1.5ms wide (PULSOUT <pin>,750). This is described in the "Robotics with the BoeBot" tutorial.

Unsui

Thanks Mike. I think I just needed to recenter the servos. Spent a day tearing it down and rebuilding it and I didn't even think about recentering the servos. Do they need recentering often?

Mike Green

They shouldn't need "re-centering" more than once. When they're initially made, their control pot could be anywhere in its range. Once adjusted, they should keep their setting for a long time.