animated rotating radar

[patgingras]

Hi,

How to animate rotating radar? I first thaught about small dc motor but they turn too quickly....
Thanks

[Akula]

Usa a gearhead motor. It has reduced rotation due to it's gear set up

B

[Admhawk]

Use a $20 micro servo, already has the gears. Just remove the variable potentiometer link and use it to adjust speed. Works nicely on the RC ships.

[Guest]

Micro servo looks nice but I'm not sure I understand what you say about the potentiometer link....

[Admhawk]

As a package, the servo turns gears which are connected to the output shaft and also to an internal potentiometer. As the gears turn, the pot turns, stopping the servo in it's new position commanded by the radio. If you physically pull the pot away from the gears, you lose the feedback it provides. There are a couple of mods needed, this page will help with the details: http://www.seattlerobotics.org/encoder/ ... 3003C.html

[Guest]

Can I simply connect them to the power source without modifying them? Do I need a servo controller?

[Admhawk]

The article explains how to modify them so that they turn continuously. Once modified, connect direct to a dc power source. No controller req'd.

[Sean Hert]

There are a couple of mods needed, this page will help with the details: http://www.seattlerobotics.org/encoder/ ... 3003C.html

That's a nice reference! Thanks Darren!

[Guest]

I'm not sure that I have the electronical knowledge to do that.....
What's happened if I plug it direct to the dc power without mod?

[Sean Hert]

I'm not sure that I have the electronical knowledge to do that.....
What's happened if I plug it direct to the dc power without mod?

It depends- but most likely, the electronics go POP! and all the magic smoke escapes.

[Admhawk]

The minimum you have to do is disconnect the pot physically from the gears. Then make sure there are no stops to prevent full rotation(snip them off with a pair of side cutters)

It's been a while, and the articles are from the guys who do robot mods, IF I recall correctly (which there is no guarantee) I think I remember that when I did this, the pot controlled the speed. BUT It was a long time ago and I suffer from Mad Cow, so my memory is mush. Try it and find out.

Connect a battery to the servo wires, red to positive, black to negative and adjust the pot to see what happens, worst case, nothing, best case servo works like you want. Either way, it's only $20 or so for the servo.

If it doesn't work, remove all the electronics and put 1.5vdc across the motor and see how fast it moves. If it's too slow, put 3 v across, and keep going up till it moves the way you want.

Or not, your choice.

[Sean Hert]

Also, most hobby shops should have a selection of small gear boxes to do this as well.

I'm actually embarrassed I'd forgotten about them till now. I even have them in my store... dang.

Tamiya makes a number of gear boxes, with motor, that would allow you to adjust the rotation ratios. Stevens International also sells motors, gears and gearboxes, that should allow you to do this.

There are also 2 small geared motors made by IHC to animate their model train amusement park rides.