Stella - Daughter of Cheap1

Stella uses the same approach as 'cheap1' did, but to dress her up, I gave her a bow for her hair (a wire bow for her wire hair) and loosely followed the format that Don did for his robot (visit: www3.sympatico.ca/donroy) . To get around some of the expense, I used a STAMP2 on a proto board, an SN75441 Quad Half H driver (with heatsink) for the same motors and gears that drive Cheap1. If you build one of these, you will have to tame the motors a little. I used a simple BASIC algorithm (the pulsout command didn't work well enough for me) to give it about a half duty cycle. That slowed it enough to be manageable. Here is a sample for the BASIC Stamp2 (note that not all subroutines are defined - in particular, the 'hitwall' subroutine is user specific and is shown so you can see how to react if the robot hits something):

'definitions

Mot_R var word
Mot_L var word
ticks var word
ticks2 var word

AGAIN:

Mot_R=0 ' these ports drive Stella in reverse
Mot_L=15

for ticks2=1 to 20 ' this will drive her for about 1/2 second


Mot_R=0
Mot_L=15
gosub DRIVEMOTOR
if(IN2) then hitwall ' check external sensors as necessary

next

goto AGAIN

'this is the motor drive subroutine
'call with Mot_R and Mot_L set to the ports that you want to drive
'
DRIVEMOTOR:
for ticks = 1 to 20


HIGH Mot_R ' set the motors you want to drive
HIGH Mot_L
pause 20 ' wait for 20 mils
gosub CLEAR ' turn them off
pause 20 ' wait for 20 mils (makes the duty cycle 1/2)

next
return

CLEAR:


LOW 0
LOW 1
LOW 15
LOW 14 'my ports for the H-Bridge

return

Close up of top of Stella