DRO stuff

Hi,

First, - thanks Jon for the link to the datasheets. I have not looked at it
yet, and it may take some time.

{ the ISP problem - after a short time - I am down to 6 bps, or the line
comes to a full halt. (They are working on it) }

Why do you insist on an optical system ? Do you now something that I don't ?
Don't missunderstand me - but I would like to dwell a little more on these
other systems.

Sure, the price on these chips may be high, - but you could make a cheaper
circuit, - I think. I fully agree about the PCB layout, - I just mentioned it
could be done in some other way.

Jan wrote: ( He is to blame, if the Mitutoyo stocks went up :)
-------

> My <$100 Mitutoyo is "perfect" and just keeps on working and working and
> working... And, it is SUPER-accurate! I can't believe it

Well, this is the stuff that make me want to investigate into other than just
optical systems.



Jon wrote:
-------

>The Chinese scale has little squares about 2 mm square of copper
>on a PC board material, with the squares ocurring about every 2 cm. The
>head has a bunch of thin lines all connected to the control chip.

<snip>

> .. strips are only about 3 or 4 per mm, at the most.

How large is the area that these thin lines enclose ?
How many of them ?

Mark wrote: ( hi mark :)
----------------

> There is capacitive coupling between the parallelograms and
> the opposite surface.

Okay, am I to understand it like this: A two sided PCB board with a common
layer on one side, and these "islands" of parallelograms on the oposite side ?

What does the sensor head look like ?

Bill wrote:
-------

> ..at one time there was an article in one of the HSM magazines about a guy
> making the strips at home, maybe someone will remember it.

Could there be anything like this on a web site someplace ?

Marc wrote:
--------

> At the time some people were talking about "Induction" (If I recall)
> sensors based on very close precision bearing balls.

Any idea how to make a sensor head for this setup ?


Elliot wrote:
--------

>What the world needs is a good quadrature readout head for diode lasers.
>Does anyone know of one? Does anyone want one but me?

This you have to explain a little bit more, I don't understand what you mean.
I just don't understand the problem, and how this "readout head" should look
like.


-----------------------------------------------------

We have several systems here, - I am trying to get some ideas on how these
things works. I think the one Jon described, could be made to work with a
"bucket brigade" RC circuit, scanning each "thin" line.

For the other systems, - I don't know yet. Need more info.

But a few words about Jon's type of circuit:

I will use a 8051 as an example:

Let say you can use an analog multiplexer, or switch. Then you may have a
resistor VCC, for charging.

Then connecting this to a port pin:
- writing a "0" out, and wait a little, discharge the capacitance
- reading like,

read:
djnz value, done
mov c, portpin
jnc read
done:
; enable next read line.

( have not written anything for this cpu in years, so bare with me if this is
wrong :) - but you should get the idea.
( - note I skipped the "bucket brigade" type of thing here )

The value bytes, would get an image of the sensor area.

I wrote this as an example, and it would be nice if someone had some clever
ideas.

Last, more descriptions on the various sensors/systems is of value.

//ARNE