Servo Receiver. What exactly is it?

[bhavik1993]

Hey guys. Im really new to robotics. I need some help with the servo receiver. What exactly is it??? Does it come with the servo itself? I bought an unknown brand of servo, at least, its unknown to me. It came with no instructions, so i thought u guys could help me out. Its got 6 wires, divided to 2 pairs of 3s. The guy in the shop said 3 is for forward and the other 3 in the opposite direction. Also, does it rotate when it is connected to a 9v battery or does the receiver have to be plugged in as well?
Pls help.

[happy_hippo]

Hello  
I'm not really good at those things either, but sounds like a stepper motor rather than a servo: http://tinyurl.com/62sqyeh And you need a stepper drive, which provides pulsing current for those motors. It's only a guess though, I'm sure some more experienced people will reply soon  

Also, have a look here : http://www.societyofrobots.com/actuators.shtml

http://www.picaxeforum.co.uk/showthread.php?t=2975
http://radiocontrolzone.com/showthread.php?t=249436
http://newsgroups.derkeiler.com/Archive/Comp/comp.robotics.misc/2005-11/msg00087.html

Hmm, after reading a little bit, it might be a servo but with strange electronics, here is what I found:

>We pulled it apart, clipped the wires to the receiver board, and
>started disassembling the motors. The rear motor assembly has two
>motors; one operates what appears to be a high/low gear shift, and
>the other is the drive motor proper.
>
>The steering mechanism looked normal enough, but it had a _lot_ of
>wires going to it: two to the steering motor, and _five_ to what
>turned out to be a multi-pole rotating switch! Using a meter we
>were able to determine which wires connected to which, but we
>haven't been able to make any sense out of _why_ the connections are
>made the way they are.
>
>We measured the switch with the steering in five different
>positions: Full Left, Partial Left, Center, Partial Right, and Full
>Right. The five wires (White, Red, Green, Yellow, Blue) are
>switched together as follows:
>
>FullLeft: Red-Green, White-Blue
>PartLeft: Red-Green
>Center: Red-Yellow
>PartRight: White-Blue (?? looks like an error)
>FullRight: White-Green, Red-Blue
>
>Part of it almost makes sense:
>
> FullLeft FullRight
>
> Red----Green ==> Red----\ /---Green
> \/
> /\
> White---Blue White--/ \---Blue
>
>Looks like a polarity reverser. But (a) the wires didn't go to the
>motor, they went to the receiver board, and (b) even if they had,
>why only reverse the motor at the _ends_ of its travel?
>
>We'd _like_ to use this switch to sense steering position. If
>anyone can offer any suggestions on how to interpret this switch for
>use with digital inputs they would be very much appreciated.
>
>Product details: RadioShack Razer
>Catalog # 60-4134 (on the "licence plate")

[waltr]

Post a link to the data sheet or at the very least a picture of what you bought.

A rotating device with 6 leads could be any number of things.

What do you need it for? Can you return it?

[bhavik1993]

Hey guys. This is the pic of the servo. Its for the wheels for the robot in the $so tutorial. What about the receiver? Does it come with the servo?

[happy_hippo]

that looks like a small stepper motor:

http://tiny.cc/zfowx

In particular looks similar to PF35T-48L4
http://tiny.cc/f7rhg
http://tiny.cc/tjiiz
(see datasheet in those links)

Read about stepper motor drivers, which basically provide required current pulses for that stepper motor. And as I understand you need something like AXON to control your stepper drive as well.

[bhavik1993]

Well, assuming i get the hitec servo as suggested in the tutorial, does the receiver come with it? Or is the receiver the avr thing that we only plug into later?

[garrettg84]

A servo is a self contained unit. It is controlled by varying pulse width in pulse width modulation.
http://en.wikipedia.org/wiki/Servo_motor#RC_servos


That stepper motor is still pretty cool though. Look up stepper motor controllers or make your own.

[bhavik1993]

Ok, about the servo, 2 of the wires connect to the battery right? and where does the signal wire connect to?

[garrettg84]

Ok, about the servo, 2 of the wires connect to the battery right? and where does the signal wire connect to?

2 of the wires do connect to power and ground, you are correct. The signal wire would connect to your micro-controller. There are tons of micro-controllers and ready made dev boards such as Arduino and Axon.

You can also make a servo tester/controller out of a 555 timer.
http://hades.mech.northwestern.edu/index.php/555_Servo_Circuit

A 555 timer can be had for next to nothing, they are incredibly cheap.
http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/LM555CN/?qs=sGAEpiMZZMuMkwKcEjFF1DrheT6R%2fb3WC6eNeLg0W1I%3d