Searching \ for 'Linear sensor input for PIC16F84' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/ios.htm?key=sensor
Search entire site for: 'Linear sensor input for PIC16F84'.

Truncated match.
PICList Thread
'Linear sensor input for PIC16F84'
1998\01\09@163403 by PHXSYS

picon face
ello

I need a very accurate linear position sensor, that can measure verticle
object travel of approx 1.5 inches. Cost is an issue. It will be an input for
a PIC16F84, so a digital signal would be less work.

Can anyone help?

Thank you

Jon Petty

1998\01\10@033602 by Leon Heller

flavicon
picon face
In message <spam_OUT610ad388.34b69691TakeThisOuTspamaol.com>, PHXSYS <.....PHXSYSKILLspamspam@spam@AOL.COM> writes
>ello
>
>I need a very accurate linear position sensor, that can measure verticle
>object travel of approx 1.5 inches. Cost is an issue. It will be an input for
>a PIC16F84, so a digital signal would be less work.

You haven't specified the accuracy you need!

How about an arrangement using a rotary encoder with a gear/ratchet
assembly?

Or, adapt the technique used in digital calipers. I think that they use
some type of low-cost capacitive sensor. Moire' fringing is an optical
technique sometimes used for this type of application.

Leon
--
Leon Heller: leonspamKILLspamlfheller.demon.co.uk http://www.lfheller.demon.co.uk
Amateur Radio Callsign G1HSM    Tel: +44 (0) 118 947 1424
See http://www.lfheller.demon.co.uk/dds.htm for details of my AD9850
DDS system - schematic and software.

1998\01\10@034001 by XYGAX

picon face
I need a very accurate linear position sensor, that can measure verticle
object travel of approx 1.5 inches. Cost is an issue. It will be an input for
a PIC16F84, so a digital signal would be less work.

Can anyone help?

Try this....
Mouse ball princable and a fixed sensor to check end of travel......
a slotted (laser etched) strip and a slotted opto switch with an additional
switch opto or mechanical to indicate 'home'
Alternatively if the mirco is controling the movement a single switch to
signify end of travel and a steppermotor driving a worm gear to move the
object sorting out the position is a matter of counting steps.
Alternitivly read the thread on 'reading a pot without a-d and use a pot

Just a couple of ideas....

Cheers Steve............

1998\01\10@080650 by mike

flavicon
picon face
In message  <.....610ad388.34b69691KILLspamspam.....aol.com> EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU writes:
> ello
>
> I need a very accurate linear position sensor, that can measure verticle
> object travel of approx 1.5 inches. Cost is an issue. It will be an input for
> a PIC16F84, so a digital signal would be less work.
>
> Can anyone help?
>
Jon,

Several methods come to mind some cheap, some not so:

o LVDTs  (not so cheap and will need external conditioning, but
          very reliable).

o Slider POTS  (cheap and can be directly interfaced to C84 as
                as recent thread has explored).

o Sony MagnaScale (not so cheap, but with quad encoded output
                   so direct connection to C84 is possible).

There other methods which I'm sure others will mention.


Regards,


Mike Watson

--
Denison Mayes Group

1998\01\11@153630 by Andrew Mayo

flavicon
face
You could possibly take two low-cost ultrasonic transducers and mount
one on a fixed base and the other on the sliding part, then pulse the
transmitter and measure the delay to the receiver. From memory the speed
of sound is approx 300m/s so 1.5 inches will provide a delay of around
100uS if my quick math is correct. This method is, however, sensitive to
variations in temperature as the air density changes, but I don't know
how significant this would be.

{Quote hidden}

1998\01\11@164037 by Tom Handley
picon face
  Jon, I'd suggest using a 16C71/710/711/715 as they cost less than a 16x84
and they have up to 4 channels of A/D built-in. Then use a simple linear pot.
Depending on the selection of the pot, you can get very good resolution. The
best resolution usually comes from LVDTs but they are expensive and usually
require a lot of analog `glue'. Optical-based sensors are another option but
they are also more expensive, require more I/O, and like LVDTs, they require
more software. I've seen a lot of discussion here about using a 16x84 for
analog input. However, the above parts cost less, are pin compatible as well
as software with the exception of the A/D configuration registers. If you
only have a 16x84 programmer, then I'd recommend an external serial A/D or
John Payson's suggestion of an R/C-based A/D. Personally, I'd avoid gears
and magnetic tape ;-)

  - Tom

At 04:28 PM 1/9/98 EST, you wrote:
{Quote hidden}

More... (looser matching)
- Last day of these posts
- In 1998 , 1999 only
- Today
- New search...