Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2971479 for flyrotary@lancaironline.net; Mon, 02 Feb 2004 16:59:22 -0500 Received: from edward (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i12LxIaM007198 for ; Mon, 2 Feb 2004 16:59:20 -0500 (EST) Message-ID: <004501c3e9d7$cf46f400$2402a8c0@edward> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Linear Position Transducer? Date: Mon, 2 Feb 2004 16:59:18 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0042_01C3E9AD.E5C2F8C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0042_01C3E9AD.E5C2F8C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Now, that's what I like about this group. Aways someone with a = brilliantly simple solution to my complex problems. Thanks Bill. That just might be ticket! Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Bill Schertz=20 To: Rotary motors in aircraft=20 Sent: Monday, February 02, 2004 3:20 PM Subject: [FlyRotary] Re: Linear Position Transducer? Why not a simple (regular rotational) potentiometer. Put a disk on the = shaft that is the circumference of the max travel that you need, wrap a = string around the disk, attached at each end to the manifold parts, and = then movement of the manifold will cause the shaft of the pot to rotate, = and the rotation will be constrained to less than 1 revolution. Bill Schertz [FlyRota] Re: Linear Position Transducer? Message 35 of 35 =20 From: Finn Lassen Add Contact =20 Sent: 2/2/2004 11:09:26 AM =20 To: flyrotary@lancaironline.net =20 Cc: =20 Subject: [FlyRotary] Re: Linear Position Transducer?=20 Attachments: =20 Actually, giving it another thought, the cheapest and = easiest,would probably be to use the innards of an old mouse. Wrap a spring-loaded string (waxed?) several turns around the = shaft of one of those small wheels in the mouse. Remember the frequency = indicators on real old radios? (In this case it will be the string = moving the axle, not the axle moving the string). Hook up a scope to the mouse: pin 5 is ground. Pin 2 or 3 is = output, and one of the other pins supply the power. Examine the output. Your circuit will have to be designed to remember the last = position before power-down, or you can simply move the manifold to an = end-stop and reset the position counter. Finn Finn Lassen wrote: Hi Ed, This is off-the-wall, but what is used in the $20 electronic = dial calibers? Maybe it's possible to pick up the signals to the LCD = segements... I told you it was off the wall. Now, you can make your own: Need a strip of binary tape: one strip is black 1/2 the length = white the rest, the second stripe is black-white-black-white, the third = twice as many black-whites, etc. down to the resolution you want. Then a = number of led/photo-transistors pickups that can read the stripes.=20 The easier way is of course just one stripe and your circuit = just counts the changes as the stripe passes through the = led/photo-transistors reader - but requires the circuit remembers the = current position. Also some way to determine direction. Take apart an old mouse and see how that works. There must be 10's of ways to do this. Finn Ed Anderson wrote: Hi Guys,=20 I am finishing up the design and fabrication of my = variable length EDDIE intake and need some assistance. I want to use a = voltmeter (or LEDs) to indicate the postion of the manifold. The = simplist approach would appear to have a linear resistor attached such = that its arm is moved as the manifold moves thereby changing the = resistance indicating distance. =20 I've done a lot of Web surfing and found a number of linear = postion potentiometers. The problem is they cost more than I have = invested in the manifold. Regular audio linear potentiometers do not = have the mechanical range I need. I need a position indictor that has = at least 5 1/2 - 6" of travel. Anyone have any ideal where something = reasonably priced might be found. =20 If you know of a retail catalog that have such things I'd = appreciate a pointer. I can find plenty of Linear Postion = Potentiometers - but they cost in the hunderds of $$. Need something = much cheaper. =20 I know I could devise a 3:1 lever ratio or some such thing = and use one of the cheap (but mechanically range restricted) linear = potentiometers for audio circuits, but would rather not. Thanks Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC=20 ------=_NextPart_000_0042_01C3E9AD.E5C2F8C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Now, that's what I like about this = group. =20 Aways someone with a brilliantly simple solution to my complex=20 problems.
 
Thanks  Bill.  That just = might be=20 ticket!
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 Bill=20 Schertz
Sent: Monday, February 02, 2004 = 3:20=20 PM
Subject: [FlyRotary] Re: Linear = Position=20 Transducer?

Why not a simple (regular rotational) potentiometer. Put a disk = on the=20 shaft that is the circumference of the max travel that you need, wrap = a string=20 around the disk, attached at each end to the manifold parts, and then = movement=20 of the manifold will cause the shaft of the pot to rotate, and = the=20 rotation will be constrained to less than 1 revolution.
 
Bill Schertz
 
 [FlyRota] Re: Linear = Position=20 Transducer? Message 35 of 35 =20
 From:   Finn Lassen=20 Add Contact =
 Sent:   2/2/2004 = 11:09:26 AM=20
 To:   flyrotary@lancaironline.net
 Cc: 
 Subject:   [FlyRotary] Re: Linear Position = Transducer?
 Attachments:    =
Actually, giving it another thought, the cheapest and = easiest,would=20 probably be to use the innards of an old mouse.
Wrap a = spring-loaded=20 string (waxed?) several turns around the shaft of one of those = small=20 wheels in the mouse. Remember the frequency indicators on real = old=20 radios? (In this case it will be the string moving the axle, not = the=20 axle moving the string).

Hook up a scope to the mouse: = pin 5 is=20 ground. Pin 2 or 3 is output, and one of the other pins supply = the=20 power.
Examine the output.
Your circuit will have to be = designed=20 to remember the last position before power-down, or you can = simply move=20 the manifold to an end-stop and reset the position=20 counter.

Finn

Finn Lassen wrote:
Hi=20 Ed,

This is off-the-wall, but what is used in the $20=20 electronic dial calibers? Maybe it's possible to pick up the = signals=20 to the LCD segements... I told you it was off the = wall.

Now,=20 you can make your own:
Need a strip of binary tape: one = strip is=20 black 1/2 the length white the rest, the second stripe is=20 black-white-black-white, the third twice as many black-whites, = etc.=20 down to the resolution you want. Then a number of=20 led/photo-transistors pickups that can read the stripes. =

The=20 easier way is of course just one stripe and your circuit just = counts=20 the changes as the stripe passes through the = led/photo-transistors=20 reader - but requires the circuit remembers the current = position. Also=20 some way to determine direction.

Take apart an old = mouse and=20 see how that works.

There must be 10's of ways to do=20 this.

Finn

Ed Anderson wrote:
Hi Guys,
 
    I am = finishing up=20 the design and fabrication of my variable length EDDIE = intake and=20 need some assistance.  I want to use a voltmeter (or = LEDs) to=20 indicate the postion of the manifold.  The simplist = approach=20 would appear to have a linear resistor attached such that = its arm is=20 moved as the manifold moves thereby changing the resistance=20 indicating distance. 
 
I've done a lot of Web = surfing and=20 found a number of linear postion potentiometers.  The = problem=20 is they cost more than I have invested in the = manifold. =20 Regular audio linear potentiometers do not have the = mechanical range=20 I need.  I need a position indictor that has at least 5 = 1/2 -=20 6" of travel.  Anyone have any ideal where something = reasonably=20 priced might be found. 
 
 If you know of a = retail catalog=20 that have such things I'd appreciate a pointer.  I can = find=20 plenty of Linear Postion Potentiometers - but they cost in = the=20 hunderds of $$.  Need something much cheaper. =20
 
I know I could devise a 3:1 = lever ratio=20 or some such thing and use one of the cheap (but = mechanically range=20 restricted) linear potentiometers for audio circuits, but = would=20 rather not.
 
Thanks
 
 
Ed Anderson
RV-6A N494BW = Rotary=20 Powered
Matthews,=20 = NC
=
------=_NextPart_000_0042_01C3E9AD.E5C2F8C0--