There are commercially made digital up/down counters readily available. There are also binary and decimal up/down counter ICs that are fairly cheap. the binary or BCD data could feed a digital display or just a binary readout to interpret in ones mind. The up/down counter can be driven directly from the quadrature encoder. A simple reset circuit can put the zero at the start of the measurement, making things simpler. So that is another way to go.

 

I have a 50' and 100' flat tapes as well as the FatMax 26' tape. Have used them for years measuring diameters and circumferences of steel tanks. Little Trigonometry to locate fittings welded on such tanks. Have used ultrasonic measuring tools accurate to 1/4 inch (where ± 1/2" tolerances were acceptable).

What are you measuring; besides "circumferences"? What tolerances are you working with? Is this industrial or something you're building for your child or grandchild? Everybody has advice on how to reach the moon when we have no idea where you're really going. You COULD be going to Trenton NJ. Or the Falkland's. You could be throwing a dart or pitching horseshoes. What are you measuring and how much accuracy do you need? You DID say 1mm. I've worked with tolerances and measurements down to 25 microns. And I've worked with tolerances as open as 3". All have specific tools and needs. We can help if we know what you're doing. Otherwise we're just clicking away on our keyboards and in some cases arguing points that we don't know whether they're germane to the subject or not. We Need Input.

 

If real accuracy is needed on a large circumference, one too big for a micrometer or caliper, in machining you reach for a PI Tape. They are as accurate to the thousndth of an ench as a micrometer. https://www.pitape.com/products.htm

 

They are as accurate to the thousndth of an ench as a micrometer.

@shortbus: What's an "Ench"? Is that something that steals Halloween?

 

The TS asked for 1mm accuracy and I replied with a means of getting that accuracy. Some of those "smart" answers were not even a bit funny.
And an "Ench" is clearly a typo. some of us "fatfinger"and do not always catch the errors.

 

@shortbus: What's an "Ench"? Is that something that steals Halloween?

That's a highly technical term us trained machinist use. They will pull my journeymans card if they find out I used it in public.

 

The TS asked for 1mm accuracy and I replied with a means of getting that accuracy. Some of those "smart" answers were not even a bit funny.
And an "Ench" is clearly a typo. some of us "fatfinger"and do not always catch the errors.

Settle down Mister Bill. I knew from the very start it was a fat fingered typo. But you must admit, that's a pretty fat finger to use the right middle finger that normally types an "I" and accidentally hit an "E".

Just an observation, but you're often critical of a lot of us who are having some fun. Has the Covid lifestyle really got you down that much that you have to fire missiles at everyone? Chill. Let us stupid ones be stupid. You can't fix stupid.

 

Settle down Mister Bill. I knew from the very start it was a fat fingered typo. But you must admit, that's a pretty fat finger to use the right middle finger that normally types an "I" and accidentally hit an "E".

Just an observation, but you're often critical of a lot of us who are having some fun. Has the Covid lifestyle really got you down that much that you have to fire missiles at everyone? Chill. Let us stupid ones be stupid. You can't fix stupid.

Given that this site is providing advice and information for folks all around the world, some of those folks may not understand that some of the remarks are "just having fun" and actually take them as legitimate advice. A large part of my career has included providing advice that was rather important towards keeping things from getting ugly and either losing production or causing damage to either equipment or people. Thus it has always been important to provide good instructions and information.
And on occasion some of the responses have just plainly been far off base.

And perhaps mister shortbus had originally started a different word and then changed the thought. That happens to me, fortunately spellcheck provides a warning most of the time.

 

I'm sure the difference between "ench" and "inch" isn't going to blow up someone's Generac generator. And I didn't realize you're the self appointed police of AAC. I thought it was a moderators job.

Now, concerning ourselves with the TOS and Community Guidelines, we really need to get back and stay "On Topic". So by self admission - I deviated for a moment.

What kind of sensor can (be) used for measuring tape? Since measuring tapes are not accurate down to a mm or a thousandth of an inch I'm not assuming the TS wants something as accurate as that. However, given that he DID state he wants something that can count at 1mm - - - that's a pretty tight tolerance. To achieve that kind of measurement an instrument (in inspection terms) should be capable of measuring 0.1mm.

We would be better able to answer the TS question if we knew his intended use and required accuracy. Otherwise you (mister bill) and I are going to differ in our approaches and advice. However, I don't think anything or anyone is going to be hurt with a tape measure. Now, if we were discussing how to measure 480VAC - that would require much more care and understanding in how we answer such questions. It's one reason why I avoid answering questions that can lead to equipment harm or destruction or injury or death.

Personally, I've grown weary of being belittled for my difference of opinion in many cases. It's OK to disagree. And no - I don't care to take this to private messaging. It happens in public, so maybe one of us should start a thread in "Off Topic" about it.

 

A large part of my career has included providing advice that was rather important towards keeping things from getting ugly

A lot of your answers don't reflect that. Tony and I are friendly here and probably would be in person. So rather than stick up for me and start a argument, leave it between the two of us. Got it?

 

@shortbus: What's an "Ench"? Is that something that steals Halloween?

Its a contraction commonly used when making a rough measurement, " Eh, make it an inch" .
Max.

 

A lot of your answers don't reflect that. Tony and I are friendly here and probably would be in person. So rather than stick up for me and start a argument, leave it between the two of us. Got it?

When I said "ugly" it was in terms of preventing ugly injuries or damage. Not personal.

 

providing advice that was rather important towards keeping things from getting ugly and either losing production or causing damage to either equipment or people.

When I said "ugly" it was in terms of preventing ugly injuries or damage. Not personal.

That was the way I took it - to mean damaging or injuring persons or property. And for public record, yeah, I think SB and I would be pretty good friends. Popping a beer over a camp fire with fishing rods in hand.