tailieunhanh - McGraw.Hill PIC Robotics A Beginners Guide to Robotics Projects Using the PIC Micro eBook-LiB Part 7

Tham khảo tài liệu ' pic robotics a beginners guide to robotics projects using the pic micro ebook-lib part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Walter s Turtle 107 2 2 11 8 in 11 8 in 1 8 -in hole Figure Side dimensional view for hole placement in top of the upper bracket. 6-32 machine screw 6-32 nut 6-32 nut n. 6-32 . Soldered brass nut wire 1-in-long compression 6-32 spring 1 2 machine screw 6-32 nut 1-in-long compression spring __ Figure Side view of upper bracket detailing the mounting of the upper bracket to the robot base using machine screws and compression springs. Also details bracket half of the bumper switch. Mounting the Steering Servomotor If you haven t done so mount the steering servomotor to the robot base using four 6-32 plastic machine screws and nuts. Before you attach the U bracket to the steering servomotor make sure the steering servomotor spindle is in its center position. This will ensure that the robot will steer forward right and left 108 Chapter Eight Figure Side dimensional detail robot base side of the bump switch of plastic screw with top brass nut. Figure Close-up photograph detailing bump switch and spring mounting of upper bracket. properly. The following short program will place a servomotor in its center position start pulsout 150 pause 18 goto start The output pulse signal for the servomotor is taken as pin RB1. Once the servomotor is in its center position attach the U bracket to the servomotor so that the drive wheel is pointing forward. Walter s Turtle 109 Figure Close-up photograph detailing bump switch. Photoresistor The CdS photoresistors see Fig. used in this robot have a dark resistance of about 100 kn and a light resistance of 10 kn. The CdS photoresistors have large variances in resistance between cells. It is useful to use a pair of CdS cells for this robot that matches as best as one can match them in resistance. Since the resistance value of the CdS cells can vary so greatly it s a good idea to buy a few more than you need and measure the resistances to find a pair whose resistances are close. There are a few ways