HELP with a servo

[chris69randy]

hi gang

i need some help, i need to make a servo which goe's on and off from a click of a button, what i mean is i want to make it turn full one way when swicthed on and full the other way when switched off.

i know servo's have a 5volt pulse and need to get around this some how so PLEASE PLEASE HELP and bear in mind i am not a tech freak so please be simple for me.

ps. its not being used with a controller, its going to be used in a real car

thanks
chris

[Al_The_Man]

It looks like you don't really need a servo, just a point to point positioner, there are many of these motorized circuits like you describe already in use in a full size auto. e.g. automatic trunk open/closer, auto window opener with electronic circuit breaker, just to name a couple. Get hold of a schematics of a high end auto with these features and adapt Possibly.
Al

[chris69randy]

thanks for the info but the reason i say servo is because that is the size if not smaller i need for my project.

if you could point me in the right direction that would help me loads.

thanks again
chris

[Al_The_Man]

thanks for the info but the reason i say servo is because that is the size if not smaller i need for my project.

The word Servo by itself does not indicate size, how small do you want to keep it, what kind of load are you putting on the motor?
Al

[ty1295]

Simple DC motor, couple limit switches.
Throw switch one way, power goes to motor, goes to end hits switch which pulls power off motor.

Flip switch other way, exact opposite.

Could use some relay's in latching configuration also, with the limit breaking the latch. Would allow you to use a momentary switch to activate.

Servo typically means a AC or DC motor with an encoder. You really don't need the encoder.

[ynneb]

Possibly Chris is requesting a servo because he also wants it to hold position .

Chris, it would help if you told us what you needed to do with it. I dont know your aplication, but possibly a solinoid could do the job for you too? A soliniod will also hold the position once at the end of its stroke.

[chris69randy]

hi

thanks for all the replys, i need it to be about 15 to 20mm wide and if not smaller and i need it to flip a number plate that has been cut in half.

i thunk you can guess why i need it small, any help pointing me where to get the right parts will help so much even better if there in the uk.

thanks again all
chris

[ViperTX]

Ah Chris you want to have a messaging plate where your license plates are normall at? So, you'll use the servo to drive some mechanism in one direction to flip each plate half to your message and then when you want your plate number to show...you
ll touch a button and have it flip back?

[chris69randy]

hi

the bottom part of the plate will stay in place and only the top half will flip down just a door hinge.

thanks
chris

[Al_The_Man]

AH..... The old flip-the-number-plate trick

But as Benny suggested a solenoid may be the way to go, it is also cheaper, you should be able to get one that fits that dia, but whatever you use if it is exposed to the elements then it will need some kind of protection.
With a solenoid that moves your required distance, or potentially greater, you would not need extreme position limit switches etc. I assume you are just restricted to width of 20mm as whatever method you use you would also need an actuator of some kind attached to the motor or solenoid.
Al

[chris69randy]

HI

you see i have no idea whats what and how to do things thats why i am on here asking, so any help will do
thanks

[Al_The_Man]

A solenoid is just a metal actuator rod that is moved in a radial fashion by a DC (e.g. 12vdc) coil, You could probabally get one from your auto junk yard, they are typically used on auto's for gas tank cover openers, door locks and probabally other things I cannot think of right now.
Al
Here is a UK site that explains what a typical one looks like. http://www.blpcomp.com/productinfo/solenoids.php