Need howto for homebrew power servo

[fritz42_male]

I remember seeing somewhere a howto on how to make you own high power servos.

Does anybody have a link to this please?

[spinman1949]

Doc used a wiper motor and a driver board board from a servo that as I recall he utilized the signal output to drive some op amps. I will look for the thread. In fact I just got a recent response from him re this. Search that Dragon thread. I mentioned automating the prop and mentioned his power servo. He is in process of working on a prop using them.


Found it. http://www.hauntforum.com/showthread.php?t=12435&highlight=servo

Here is the link you want. The first link is Doc discussing how he will use the Monster Servo's

http://www.hauntforum.com/showthread.php?t=10575&highlight=mosfet

PS. I think I meant to say mosfet instead of op amps. Regardless. His thread explains how he does it.

PPS. Oh and this you will want to look at. http://www.lynxmotion.com/Product.aspx?productID=648&CategoryID=52

[fritz42_male]

Thanks very much Tom.

However none of these look like the article I saw (which wasn't on Hauntforum). I'll keep looking and will post the link when and if I find it.

[Dr Morbius]

I remember seeing one too, but I can't find it either. I'll keep looking and let you know.

[Dr Morbius]

Is this the one?
http://homepages.which.net/~paul.hills/Circuits/PowerServo/PowerServo.html

[fritz42_male]

Nope - not that one either but thanks for trying.

I have a feeling that the one I saw was based on the Lynxmotion board in Spinman's post but had lots of actual pictures showing the setup

[spinman1949]

The link Doc found made my eyes do a Marty Feldman. LOL !!!

"Holy Crappers Batman, all we want is some extra torque? "

[HomeyDaClown]

How much torque do you need?

Wiper motors vary in torque but I believe most supply between 8 and 12 ft.-pounds of torque.

You can always use a Hitec HS-805BB Mega Torque servo which is rated for
275 ounce-inches (about 1.5 ft.-pounds) of torque at 4.8V or
343 ounce-inches (about 1.8 ft.-pounds) of torque at 6.0V.

They run about $30

[fritz42_male]

A wiper motor is exactly what I was thiking of using.

In the meantime, I found this

http://www.lynxmotion.com/images/html/ht01.htm

[hpropman]

Fritz that board will not provide enough current for a wiper motor. A smaller motor maybe what are you going to be moving.

[fritz42_male]

Hi mate, the HS5475 board info says it provides up to 4.5A with 2A continuous at 6V. I'm aware that a wiper motor can pull more than this although I might do some tests to see just how much it pulls under moderate loads.

For smaller motors the HS5475 ought to be fine though - I'm going to trawl around and look for geared motors to play with.

[hpropman]

Try this one. It works really well - it should be fine for light loads ~2 lbs - I will need to check the current though I think it is about an amp. I am using one for my peeper I can test the current if you like also they are using them for FCG

[fritz42_male]

No link?

[hpropman]

sorry here it is:

https://www.surpluscenter.com/item.asp?UID=2009112315303278&item=5-1587&catname=electric

[azdude]

If you are wanting to stay with a standard servo motor system you should look here (http://www.servocity.com/html/pan_tilt_roll___accessories.html) at the "Pan" and "Tilt" systems that servo city offers. These are essentially gear boxes bolted onto standard servo motors that get you a huge increase in torque. I have used their 'medium duty' pan motors for 2 props I built and have had no problems.

[fritz42_male]

Thanks for the links guys. I also came across this link. It uses Picaxe chips as well which makes it convenient.

http://letsmakerobots.com/node/1524