Re: 6 Wire Servo
- From: Frnak McKenney <frnak@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 10 Nov 2005 16:53:44 GMT
On 9 Nov 2005 09:51:11 -0800, redbrickhat <redbrickhat@xxxxxxxxxxx> wrote:
> Could someone explain how a 6 wire servo works? I found one when I
> opened up an RC toy car from Radioshack.
>
> It has 2 wires that go to the motor and 4 wires that go to some kind of
> pot I think: on a small board are 2 etched concentric circles which are
> in contact with a 4-pronged device mated to the spinning gear. Two of
> the 4 prongs touch the outer circle, the other two the inner circle.
>
> I know how to program 3 wire servos but don't understand the purpose of
> the extra "pot" of the 6 wire servo.
redbrickhat,
I don't know if what you're describing is what my brother and I ran into
on a RadioShack "Razer", but I've appended a copy of my original post with
our test results on the off chance it may help...
Frank McKenney
>From: Frnak McKenney <frnak@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>Subject: Customizing a RadioShack R/C truck -- steering switch?
>Message-ID: <pW7qe.1757$eM6.409@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>Date: Fri, 10 Jun 2005 03:37:57 GMT
>
>I was up in Selkirk a few weeks back for my niece's graduation from
>Rensselaer, and I took along a present for my brother Bruce: a
>transmitter-less battery-less RadioShack "Razer" truck. He has been
>looking for something to hook up to the Philips LPC-series ARMs he
>has been playing with, and, for $3 this seemed like the perfect
>gift. <grin>
>
>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")
>
> http://support.radioshack.com/productinfo/DocumentResults.asp?
> sku_id=60-4134&Name=RadioShack%20RC%20Toys&Reuse=N
>
> Provides some documentation and a parts list, which includes:
>
> MANUAL,SERVICE 60-4134 MS6004134 (part#s, but no manuals)
> MANUAL,USERS 60-4134 MU6004134
>
>Ah, well. Another week, another mystery.
>
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)
--
Knowledge does not necessarily imply judgment. All truly
critical, as against technical, argument is either intuitive or
hypothetical or partial. This cannot be compensated for by a
study of the raw material, however exhaustive.
-- Robert Conquest, "The Dragons of Expectation"
--
.
- References:
- 6 Wire Servo
- From: redbrickhat
- 6 Wire Servo
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