The servo is an inexpensive TS-53 servo from Tower Hobbies. A wooden type of thread spool is attached to the servo control horn using thumb tacks. If the smaller six arm control horn is used, then the sides of the thumb tacks have to be snipped off to fit the small size of the control horn. Using the small control horn allows the thread spool to be placed close to the side of the blind. The larger four prong control horn can be used, but it will require the thread spool to be placed away from the blind for clearance (but it still works OK). A bag of the wooden thread spools can be found in the craft section at WalMart. The center hole in the thread spool allows the servo control horn screw to be removed easily with a small screwdriver for control horn adjustment. A thunb tack is put in the side of the spool for attaching the strings that will turn the blind tilt rod.
The servo is attached to a small piece of wood for it's base. This wood piece is 2.75" long, 1" wide, and .25" thick (it has to be thick enough to account for the mounting tabs on the servo sticking out). If the servo horn is to be placed close to the blind, then a hole needs to be made in the wood to make room for the wires comming out of the servo. The servo can be attached to the wood using hot glue, but use enough so it doesn't pull lose. I used a paper clamp to hold the wooden base to the side of the blind. You may want to use something more substantial, but the simple clamp setup allows easy removal.
The mini blind needs to be modified so that the tilt rod in it is free to be moved by the servo strings. The tilt string spools on the tilt rod in the mini blind snap out of their holders. When snapped out, the tilt rod can be positioned such that the blind wand turning gizmo on the tilt shaft can be slid off the end of the rod. This has to be removed to allow the the tilt rod to be freely rotated by the servo. It can be put back on later if you decide to go back to the manual blind tilting. String is attached to the black string spools on the blind tilt rod which is pulled by the servo spool to rotate the blind tilt rod. A top and bottom string is attached to the tilt rod spool and wrapped atleast one turn in each direction around the tilt rod spool. A small hole is made in the bottom of the blind side for the bottom string to go through. The top string goes over the top of the blind side. Pulling on these strings will cause the blind tilt shaft to rotate. Pulling the bottom string will rotate the shaft one direction, and pulling the other string will rotate the shaft the other direction. The servo will only rotate 1/2 turn, but this is enough to get good tilting on the blind tilt shaft. I put a little Vaseline where the tilt rod spool snaps in so it is lubricated a little against the side pull of the servo strings.
For initial setup, I found it best to have the blind out of the window and setup for testing by hanging it from a piece of wood. I set the servo and servo spool so that the closed position would get a good close. This left enough play to still get full open and some up tilting also. You will need to operate the servo a number of times to get the slack out of the string and make final adjustments. You don't want to have the servo straining against the blind in an extreme position, and this will put extra wear on the servo. This setup is just a fun experiment for a cheap blind tilt control. This setup can be controlled via the web, or by using simple batch files, the windows scheduler can adjust the blinds at desired times in desired positions. Cheap computer controlled blind tilting. I'll add more to this page in the future. As usual, YMMV!
