Assembling pantilt Mechanism

Version 8 (Rich LeGrand, 02/19/2014 11:03 pm)

1 1 Rich LeGrand
h1. Assembling pan/tilt Mechanism
2 1 Rich LeGrand
3 2 Rich LeGrand
The pan/tilt mechanism when combined with Pixy, makes a fun demo — a good “hello world” for Pixy (no Arduino required). The Pixy pan/tilt mechanism comes in a kit and requires some assembly.
4 2 Rich LeGrand
5 3 Rich LeGrand
You will need (in addition to a Pixy and a pan/tilt kit):
6 2 Rich LeGrand
7 3 Rich LeGrand
A small phillips screwdriver
8 3 Rich LeGrand
!{width: 15%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4409_zpsc3cbdd1e.jpg!
9 1 Rich LeGrand
10 3 Rich LeGrand
pliers
11 3 Rich LeGrand
!{width: 15%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4439_zps05b710ee.jpg!
12 1 Rich LeGrand
13 3 Rich LeGrand
small wire cutters
14 3 Rich LeGrand
!{width: 15%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4408_zps1c3bcd31.jpg!
15 3 Rich LeGrand
16 5 Rich LeGrand
1. Find one of the long servo horns inside one of the servo baggies, and clip it on the 3rd hole from the end.
17 1 Rich LeGrand
18 5 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4410_zps82449577.jpg!
19 5 Rich LeGrand
20 5 Rich LeGrand
2. Put the servo horn on the servo and check both ends of travel.  You can do this by moving the horn all the way to the right:
21 5 Rich LeGrand
22 5 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4416_zpsd12a3e33.jpg!
23 5 Rich LeGrand
24 5 Rich LeGrand
and then all the way to the left:
25 5 Rich LeGrand
26 5 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4413_zps9798e72c.jpg!
27 5 Rich LeGrand
28 5 Rich LeGrand
and adjusting the mounting angle of the horn such that the center of travel has the servo horn pointing downwards.  
29 5 Rich LeGrand
30 5 Rich LeGrand
3. Find one of the servo horn fasteners in the one of the servo baggies:
31 5 Rich LeGrand
32 5 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4419_zps96821db0.jpg!
33 5 Rich LeGrand
34 5 Rich LeGrand
and screw the servo horn tightly. (Here the servo is shown with the servo horn pointing downwards, which should be roughly the center of travel.)  
35 5 Rich LeGrand
36 5 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4424_zps1f16445f.jpg!
37 5 Rich LeGrand
38 6 Rich LeGrand
4. Remove the paper backing on the pan/tilt body (the smaller of the two acrylic parts).
39 5 Rich LeGrand
40 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4407_zps35303bd8.jpg!
41 6 Rich LeGrand
 
42 6 Rich LeGrand
5. Fit the servo mounting tab into the slot on the pan/tilt body.
43 5 Rich LeGrand
44 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4429_zps8269c65c.jpg!   
45 1 Rich LeGrand
46 6 Rich LeGrand
6. Flip the body over and thread a cable tie through the cable tie slots in the body.
47 1 Rich LeGrand
48 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4432_zpsd73f12b3.jpg!
49 6 Rich LeGrand
50 6 Rich LeGrand
7. Thread another cable tie through the other cable tie slots in the body. 
51 6 Rich LeGrand
52 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4437_zps6dac410d.jpg!
53 6 Rich LeGrand
54 6 Rich LeGrand
8. Tighten both cable ties by using pliers.  It requires quite a bit of force to fully tighten!
55 6 Rich LeGrand
56 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4443_zpsce8af564.jpg!
57 6 Rich LeGrand
58 6 Rich LeGrand
9. Take the 2nd servo and place in the other hole in the body as shown in the picture.
59 6 Rich LeGrand
60 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4447_zps01732746.jpg!
61 6 Rich LeGrand
62 6 Rich LeGrand
10. Take two longer 4-40 fasteners:
63 6 Rich LeGrand
64 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4450_zpsef1fd3ab.jpg! 
65 6 Rich LeGrand
66 6 Rich LeGrand
and use the secure the 2nd servo. 
67 6 Rich LeGrand
68 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4452_zps04360faf.jpg!
69 6 Rich LeGrand
70 6 Rich LeGrand
11. Take all five right-angle brackets out and examine them.  Notice that three of them have *two* threaded holes and and two of them have *one* threaded hole. We'll call these two-threaded and one-threaded brackets, respectively.  
71 6 Rich LeGrand
72 6 Rich LeGrand
Grab a two-threaded bracket.  If you look really closely, you'll notice that one of its legs is ever-so-slightly longer than the other.  Say what?  It's true--- I don't know why.  But you can best see this by looking at the holes in the bracket.  One of the holes in centered in its leg and the other hole is not centered, because its leg is slightly longer.  Weird. 
73 6 Rich LeGrand
74 6 Rich LeGrand
Take two longer 4-40 fasteners and attach two two-threaded brackets to the body as shown in the pictures below. Attach them such that the short legs are touching the body and the long legs are pointing up. 
75 6 Rich LeGrand
76 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4459_zpsb9d2579b.jpg!
77 6 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4462_zpsc4fd1782.jpg!
78 6 Rich LeGrand
79 7 Rich LeGrand
Nice. Now put this assembly aside for now. 
80 1 Rich LeGrand
81 7 Rich LeGrand
12. Take your Pixy and attach two one-threaded brackets to it as shown in the picture below.  Use two shorter 4-40 fasteners to do this. 
82 7 Rich LeGrand
83 7 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4397_zps5f38de0e.jpg!
84 7 Rich LeGrand
85 7 Rich LeGrand
13. Take two nylon bushings and press them into the non-threaded holes in these brackets.
86 7 Rich LeGrand
87 7 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4403_zpsd327e530.jpg!
88 7 Rich LeGrand
89 7 Rich LeGrand
14. Slide the Pixy into the body assembly as shown. Use two longer 4-40 fasteners to hold the two assemblies together.  Don't tighten these fasteners too tight or it will cause binding. (This is the tilt axis and you want it to move freely.)  Also make sure that the brackets are mounted squarely--- this can cause binding also. 
90 7 Rich LeGrand
91 7 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4464_zps69f05fa8.jpg!
92 7 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4465_zps9531a35f.jpg!
93 7 Rich LeGrand
94 8 Rich LeGrand
15. Plug in the servo wires into the servo connector on Pixy.  the Pan axis goes on the left and the tilt axis goes on the right, and the yellow wires on both connectors face up.  (Which is the tilt axis?  It's the one with the servo horn.)     
95 8 Rich LeGrand
96 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4467_zps1d3003b9.jpg!
97 8 Rich LeGrand
98 8 Rich LeGrand
16. Use a cable tie to secure the wires to the body as shown.  String the cable tie through the single slot in the body and around the outside.  Do not tighten the cable tie fully yet.  
99 8 Rich LeGrand
100 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4468_zpsb5c8b237.jpg!
101 8 Rich LeGrand
102 8 Rich LeGrand
17. Use the slots on the other side of the body to thread another cable tie and secure the wires on the other side as shown.  The wires are longer than they need to be, so it requires some artistic arranging.  Do not tighten this cable tie fully either.  
103 8 Rich LeGrand
104 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4469_zps29cb689a.jpg!
105 8 Rich LeGrand
106 8 Rich LeGrand
18. Verify that there is enough slack in the cables to allow Pixy to tilt fully forward and backward.  
107 8 Rich LeGrand
108 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4470_zps41e3d896.jpg!
109 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4471_zps3dc53c43.jpg!
110 8 Rich LeGrand
111 8 Rich LeGrand
19. When you're happy with the cable situation, flip over the assembly and clip the ends of the cable ties.  
112 8 Rich LeGrand
113 8 Rich LeGrand
!{width: 45%}http://i74.photobucket.com/albums/i241/cmucam/IMG_4474_zpsb45107a5.jpg!
114 8 Rich LeGrand
115 8 Rich LeGrand
20. Remove the paper backing from the pan/tilt base.
116 8 Rich LeGrand
117 8 Rich LeGrand
!{width: 45%}http://s74.photobucket.com/user/cmucam/media/IMG_4478_zpsa37b9447.jpg.html?sort=3&o=77!
118 8 Rich LeGrand
119 8 Rich LeGrand
21.
120 8 Rich LeGrand
121 8 Rich LeGrand
122 8 Rich LeGrand
123 8 Rich LeGrand
124 3 Rich LeGrand
 
125 5 Rich LeGrand
126 6 Rich LeGrand
  
127 2 Rich LeGrand
128 2 Rich LeGrand