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Step 3Mount The Pan Servo and Ultrasonic Rangefinder
The panning servo serves to pan the Ping))) horizontally for a wide range of object detection, as well as measuring distances at various angles to determine the clearest path of travel.
I used some standoffs to mount the servo, and some of the screws I had. The size you want to use for this hardware is really small; I haven't been able to find screws of the appropriate 'thread' anywhere but online. I get this hardware either from Sparkfun Electronics or Parallax (both online). Both of those retailers have all the same-sized screws and standoffs.
Now, for the ultrasonic rangefinder.
I custom-made a mounting bracket for the Ping))) ultrasonic ranger because I didn't want to have to spend the extra cash on one online. I used some plexiglass, a straight edge (razor blade), and a c-clamp for snapping the plastic apart. All you need to do to make this mount is measure the ultrasonic rangefinder, cut out two identical pieces of plexiglass a couple mm larger than the size of the ultrasonic ranger, drill the holes where necessary, and glue them at a right angle as shown. Lastly, drill a small hole just slightly bigger than the screw that came attached to the servo head, insert the screw, and then attach the whole assembly to the servo. I may be good with programming and creativity, but machining the hardware for a home-brew robot is definitely not one of my high points. So what does that mean? If I can do it, you definitely can!
Notes about the servo:
You don't have to buy specifically a Futaba S3003 like I used; you can use any servo you'd like, as long as it has a wide degree of motion; that is important for this project! I think the Futaba servo I used has ~180 degrees of motion. When I went searching for a servo to use as the panning servo for BOB, I looked for the most inexpensive one I could find, and the one I'm using does the job perfectly. If you've got a standard hobby servo with ~180 degrees of motion, then you're all set for this part, BUT-- you may need to adjust the PWM values in the source code to fit your servo, because if you don't, you may DAMAGE THE SERVO. I've ruined a servo accidentally like that before, so be careful when using a new servo; find out the 'limits' of PWM values, otherwise it will try to turn farther than it physically can (servos are 'dumb'), and it will ruin the gears inside it (unless you bought a really nice one with metal gears).
I used some standoffs to mount the servo, and some of the screws I had. The size you want to use for this hardware is really small; I haven't been able to find screws of the appropriate 'thread' anywhere but online. I get this hardware either from Sparkfun Electronics or Parallax (both online). Both of those retailers have all the same-sized screws and standoffs.
Now, for the ultrasonic rangefinder.
I custom-made a mounting bracket for the Ping))) ultrasonic ranger because I didn't want to have to spend the extra cash on one online. I used some plexiglass, a straight edge (razor blade), and a c-clamp for snapping the plastic apart. All you need to do to make this mount is measure the ultrasonic rangefinder, cut out two identical pieces of plexiglass a couple mm larger than the size of the ultrasonic ranger, drill the holes where necessary, and glue them at a right angle as shown. Lastly, drill a small hole just slightly bigger than the screw that came attached to the servo head, insert the screw, and then attach the whole assembly to the servo. I may be good with programming and creativity, but machining the hardware for a home-brew robot is definitely not one of my high points. So what does that mean? If I can do it, you definitely can!
Notes about the servo:
You don't have to buy specifically a Futaba S3003 like I used; you can use any servo you'd like, as long as it has a wide degree of motion; that is important for this project! I think the Futaba servo I used has ~180 degrees of motion. When I went searching for a servo to use as the panning servo for BOB, I looked for the most inexpensive one I could find, and the one I'm using does the job perfectly. If you've got a standard hobby servo with ~180 degrees of motion, then you're all set for this part, BUT-- you may need to adjust the PWM values in the source code to fit your servo, because if you don't, you may DAMAGE THE SERVO. I've ruined a servo accidentally like that before, so be careful when using a new servo; find out the 'limits' of PWM values, otherwise it will try to turn farther than it physically can (servos are 'dumb'), and it will ruin the gears inside it (unless you bought a really nice one with metal gears).
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