Rotating Gun turret

G'Day Bilge
Because most servos have only a 90 degree movement you need to find some way of magnifying this.
1) Use the outer hole in the Servo arm and connect to an inner hole in a similar arm under the gun house.
2) Use a sail winch servo.
I would use the first option with a "closed circuit" connection between the servo ant the gun house.
The Sail winch would also need a "closed cct" line.
Hope thisis of use.
Dai

A friend and I once spent two hours designing and building an adjustable bracket to mount a servo and gear set up to rotate a turret. Just as we were attempting to lock down the unweildy multi adjustable brackets another friend pulled up to the house. He took one look at what we were doing, and said, "why don't you just glue the servo in place?" We threw away the bracket and glued the servo right where we wanted it. It worked flawlessly.

We typically will run a 2-1 gear ratio on the servo. 3-1 is even better.
Just extend the turret mounting stud with a piece of brass tubing.
Cement a small gear to the tubing, then mount the large gear to the top of the servo arms and position it to run the turret pinion.
Chunks of plywood or acrylic are your friends for working up a mounting plate for the servo. Build a plate that hangs down below the deck. Test fit the turret's small pinion gear for height and clearance. Test fit the servo and gear for clearance on the plate. Match the gear heights. Plug in the servo and center it with your transmitter control. If it is out of center when you mount it the turret will over rotate in one direction.
The rough and tumble way to go about it would be to put silicone caulk on the side of the servo and then press it to your mounting plate and mesh the gear teeth. When the caulk is set you are good to go.

$14 dollar servo, two surplus gears, one mounting plate cut for clearances, and a dab of silicone caulk.
Turret that rotates 270 degrees, "impressive"

Thanks for the info. I will try using the servo/ gear combo. If that doesnt work I will try using electric motor/ gears but I will need a way to reverse the motor somehow. Any ideas on a cheap way to make the motor reverse? Can this be done with a micro switch/ switches? Im a total newbie with this stuff so if anyone can refer me to a diagram that might help :)
Thanks again
Bilge

Another tricky explanation.

it can be done with either two of four micro switches. It depends on how the inputs are set up.

Single switch set up.

You need to have two momentary, single pole single throw switches with three contacts.
(I typically use radio shack switches #275016A, or #275017A)
1. Common, 2. Normally closed, 3. Normally open.

The Common(C) of each switch is wired to one contact of each of the motors. It is your output. One switch for each side contact of the motor.

The Negative of your battery, input is wired to the normally closed (NC) contact of each switch.

The Positive terminal of the battery is wired to the normally open (NO) contact of each switch.
The switches are mounted on your servo so that when the servo arm rotates it presses one switch in either direction of rotation.

Now when you apply power the motor is completely grounded. The motor is receiving negative power from both switches. However when the servo presses one of the switches, it changes the polarity on that side to positive completing the circuit and the motor will power up. When the switch is released the motor will again be grounded and neutral. Pressing the other switch will cause the motor to rotate in the opposite direction.

I hope this makes sense.

Umi

done this lot's of time: to make a standard (micro)servo rotate from 90° to 360° just take the servohead of and look inside for a small piece of plastic that normaly stops the servo when the 90° is reached, just take a sharp nive or dremel and cut this piece off , viola servo rotates 360°. have used this for a ankerwinch , and is much cheaper than a sailwinch (you don't need all that power anyway)

I always find that just cutting the gear stop off is not enough.
I have to go in and disconnect the rheostat inside the servo so that it stays centered.
Then when ever the transmitter stick is moved away from the neutral point, the servo will continously rotate in one direction or other until the stick is put back to neutral. I build micro speed controls this way.
That or add resistors to fool the servo's rheostat into thinking that it has not yet reached the outer signal marker yet.

Umi

Thanks a lot for all the ideas. Really appreciate the advice. Guess ill mess around and see which one works best for this model. If i cant get it to work ill post another message for help hehe :0~
Thanks again

Bilge

This is off the subject of the rotating turret, but I have the Yamato kit without an instruction sheet. Could you provide a copy of the sheet you are working from? I'll provide the postage and any expense for the copies. Please contact me at rickl@anspach.com if you are willing to send me a copy. Thanks.