Maximum rep rate for a standard microswitch.

amdx <nojunk@knology.net> wrote in news:qlmidt$2ae$1@dont-email.me:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the
rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

It should not be. At least not electrically. The mechanical
logistics of depressing it to the click over point and then releasing
it back up to at least the reset point is likely where the bottleneck
is. You'd be better off with a reed switch. Then you would not
experience a problem until you reached the mechanical resonance point
of the reeds. Your mechanism for the actuation needs to have low
unsprung weight too to attain the rates you want.

One would think that micro and cherry would have rep rate data.

 

amdx <nojunk@knology.net> wrote in news:qlmjai$68p$1@dont-email.me:

On 9/15/2019 6:50 PM, Phil Allison wrote:
amdx wrote:

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

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the
rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?


** Try using a reed switch with a small permanent magnet, magnet
rotating switch fixed.

Many cassette decks used such an arrangement as a tape movement
sensor.


... Phil

That's sounds good, if I can find my reed switches. We had a
hurricane
11 months ago and all my supplies got reshuffled. Pain in the ass
committing the position of everything back into a new memory.

Mikek

Resort it all again and physical file it chronologically and you
will always know where to look for something based on when it was
made.

 

[amdx]

On 9/15/2019 10:13 PM, Sylvia Else wrote:

On 16/09/2019 9:45 am, amdx wrote:
I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
  It doesn't work. Unreliable counting.
  My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

                                  Mikek

How are you doing the counting?

Sylvia.

Veeder-Root counter, 12V 8 Watts.
I tried to post a Dropbox picture, lately the link in my Dropbox
window does not highlight to copy.
I had this problem then it started working, now having it again,
anyone else having Dropbox problems?

Mikek

 

On Sun, 15 Sep 2019 18:52:21 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

jla...@highlandsniptechnology.com wrote:
-------------------------------------------


6 Hz should be OK at 50% duty cycle.


** Bet JL has never tried it.

Microswitch on a drill press? OK, I confess, I've never done that.

But a small microswitch should work at 80 ms on/off time. Do you think
it won't?

I know a reed switch will easily do the job far better.

But I'm not a "designer" . ...

I don't like reeds, at least reed relays with coils. They are
expensive and unreliable. Their rated speeds are illusions, because
they bounce and twang for ages.

 

On Mon, 16 Sep 2019 08:21:42 -0500, amdx <nojunk@knology.net> wrote:

On 9/15/2019 10:13 PM, Sylvia Else wrote:
On 16/09/2019 9:45 am, amdx wrote:
I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
  It doesn't work. Unreliable counting.
  My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

                                  Mikek

How are you doing the counting?

Sylvia.

Veeder-Root counter, 12V 8 Watts.
I tried to post a Dropbox picture, lately the link in my Dropbox
window does not highlight to copy.
I had this problem then it started working, now having it again,
anyone else having Dropbox problems?

Mikek

I right-click on the file on my PC (Win 7) and select "copy Dropbox
link."

 

[amdx]

On 9/16/2019 8:21 AM, amdx wrote:

On 9/15/2019 10:13 PM, Sylvia Else wrote:
On 16/09/2019 9:45 am, amdx wrote:
I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
  It doesn't work. Unreliable counting.
  My high point is (switch closure time) about 1/12 of the rotation,
I wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

                                  Mikek

How are you doing the counting?

Sylvia.

Veeder-Root counter, 12V 8 Watts.
 I tried to post a Dropbox picture, lately the link in my Dropbox
window does not highlight to copy.
I had this problem then it started working, now having it again,
anyone else having Dropbox problems?

                             Mikek

Rebooted solved the Dropbox problem for now.
> https://www.dropbox.com/s/n2tx6mf6448d9by/counter.jpg?dl=0

Mikek

 

[John Robertson]

On 2019/09/16 6:21 a.m., amdx wrote:

On 9/15/2019 10:13 PM, Sylvia Else wrote:
On 16/09/2019 9:45 am, amdx wrote:
I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
  It doesn't work. Unreliable counting.
  My high point is (switch closure time) about 1/12 of the rotation,
I wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

                                  Mikek

How are you doing the counting?

Sylvia.

Veeder-Root counter, 12V 8 Watts.
 I tried to post a Dropbox picture, lately the link in my Dropbox
window does not highlight to copy.
I had this problem then it started working, now having it again,
anyone else having Dropbox problems?

                             Mikek

Do you have a diode on the coil of your counter? Might be one build in
if the leads of the counter are polarized from the factory. Back EMF can
play havoc with microswitches (and reed switches).
1N4002 or higher would be fine.

John :-#)#

 

[Rick C]

On Sunday, September 15, 2019 at 8:46:17 PM UTC-4, amdx wrote:

On 9/15/2019 6:54 PM, Cursitor Doom wrote:
On Sun, 15 Sep 2019 18:45:05 -0500, amdx wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

Why not use a hall-effect instead? Or laser and photo-diode with a small
mirror stuck to the side of the quill? I don't see a microswitch as being
suitable for this application.



I have a Root Veeder counter all it needs is a pulse, I wanted the
project to be counting the turns on a coil, not developing a circuit to
make a pulse to drive the counter.
Just trying to keep it simple, until I buy a lathe.
Mikek

Optical doesn't require much of a counter. Obviously you have a current limited voltage source to work with the switch. That should also work with a photo diode as long as the current and voltage don't exceed ratings. The hall sensor can be bought as a unit ready to go but it is a three wire device needing power.

Do you know what the current through the switch is when closed? What is the open circuit voltage?

If you have 5 volt power available you can get photodiode or hall modules in a couple of days.

--

Rick C.

- Get 2,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[Jeff Liebermann]

On Sun, 15 Sep 2019 18:45:05 -0500, amdx <nojunk@knology.net> wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

Sanity check. If you used a long-life mechanical microswitch, good
for a minimum of 50,000 cycles,
<https://sten-eswitch-13110800-production.s3.amazonaws.com/system/asset/product_line/data_sheet/124/MS.pdf>
at 330 revs per minute and one count per revolution, your switch will
be dead after:
50*10^3 / 330rpm = 151 minutes = 2.5hrs
If you believe the 1 million operations specification (I don't), it
might last up to:
1*10^6 / 330rmp = 3,000 minutes = 51 hrs
Be sure to have a box of replacement switches handy.

By coincidence, I recently bribed my auto mechanic with a tiny magnet
hall effect sensor tachometer for his lathe:
<https://www.ebay.com/itm/4Digital-LED-Tachometer-RPM-Speed-Motor-Car-Meter-Proximity-Switch-Senso-US/323666797728>
It won't count revolutions, but will measure RPM, which is what I
suspect you really want. I've used these on a drill press in the past
and found that contact cementing the tiny magnet to the spindle pulley
and installing the sensor between the pulleys works well.

The biggest problem was finding 12VDC near the drill press. I used a
common "wall wart" power supply because the owner didn't want me to
splice into the 117VAC power. Finding a good box was also problem.

You can also get photoelectric tachometer kits, similar to the hall
effect sensors. Gluing a reflecting piece of tape to the spindle
pulley or the belt should work.

Example:
<https://www.homemadetools.net/forum/new-rpm-meter-shop-fox-drill-press-modidication-65530>
More:
<https://www.google.com/search?q=drill+press+tachometer&tbm=isch>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sun, 15 Sep 2019 19:46:18 -0500, amdx <nojunk@knology.net> wrote:

I have a Root Veeder counter all it needs is a pulse, I wanted the
project to be counting the turns on a coil, not developing a circuit to
make a pulse to drive the counter.

Thanks. So now you disclose what you're trying to accomplish. I
assumed you wanted a tachometer for the drill press. So, use a hall
effect or photoelectric proximity sensor:
<https://www.ebay.com/sch/i.html?_nkw=hall+effect+proximity+sensor>
<https://www.ebay.com/sch/i.html?_nkw=photoelectric+proximity+sensor>

I'm not sure what you have from Veeder Root. If it's marginal, look
for an industrial counter or "totalizer":
<https://www.ebay.com/sch/i.html?_nkw=electronic+totalizer>
<https://www.grainger.com/category/electrical/industrial-controls-automation-and-machine-safety/industrial-automation/meters-counters-and-plc/counters>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sun, 15 Sep 2019 18:01:25 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 15 Sep 2019 18:45:05 -0500, amdx <nojunk@knology.net> wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

6 Hz should be OK at 50% duty cycle.
Are you debouncing the closure?

I don't think he wants to wrap half the circumference of a drill press
chuck with magnets in order to get a 50% duty cycle. A rough
estimate:

The drill chuck will be spinning at 330 rpm.
The chuck has a diameter of about 2 inches.
The magnet might be about 1/4" long.

Circumference of chuck = 1 revolution = Pi*d = 3.14 * 2 = 6.28 inches
Surface speed = 330 rev/minute = 5.5 rev/sec
= 6.28 in/rev * 5.5 rev/sec = 34.5 in/sec
A 1/4" long magnet, moving a 34.5 in/sec will product a pulse of:
0.25 in / 35.5 in/sec = 0.007 sec = 7 milliseconds
The "operating time" of a reed relay can be "a few milliseconds"
according to:
<https://www.electronics-notes.com/articles/electronic_components/electrical-electronic-relay/reed-relay-specifications-parameters.php>
Overall figures of operate time can be as low as 100ľs
although it is more often around a few milliseconds dependent
upon the actual reed relay.

In my never humble opinion, a 7 msec pulse will be rather marginal
unless either a very small reed relay, or much larger magnet is used.
There's also the minimum pulse with to trigger the Veeder Root
counter, which will be a factor. Of course, with a 50% duty cycle,
the pulse width will be half a revolution or:
1 / 5.5 rev/sec = 180 msec
which should be more than enough time to produce a count. While that
would be great for a coil winder running at 330 rpm, I suspect that
most counters will have problems at the low frequency end. Looking at
the specs on my cheap eBay counter, it only goes down to
10 Hz = 0.1 count/sec = 6 rpm
If the drill press is going to be stopped and started during the coil
winding, I would expect some counts to be lost as is slows down and
speeds up. This is one reason why many coil winders still use gear
driven mechanical turn counters that can be spun up, down, reversed,
and stopped, without losing the count.
<https://www.google.com/search?q=coil+winding+machine&tbm=isch>



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[amdx]

On 9/16/2019 11:11 AM, Jeff Liebermann wrote:

On Sun, 15 Sep 2019 19:46:18 -0500, amdx <nojunk@knology.net> wrote:

I have a Root Veeder counter all it needs is a pulse, I wanted the
project to be counting the turns on a coil, not developing a circuit to
make a pulse to drive the counter.

Thanks. So now you disclose what you're trying to accomplish. I
assumed you wanted a tachometer for the drill press. So, use a hall
effect or photoelectric proximity sensor:
https://www.ebay.com/sch/i.html?_nkw=hall+effect+proximity+sensor
https://www.ebay.com/sch/i.html?_nkw=photoelectric+proximity+sensor

I'm not sure what you have from Veeder Root. If it's marginal, look
for an industrial counter or "totalizer":
https://www.ebay.com/sch/i.html?_nkw=electronic+totalizer
https://www.grainger.com/category/electrical/industrial-controls-automation-and-machine-safety/industrial-automation/meters-counters-and-plc/counters

Hi Jeff,
This should be simple although the mounting mechanics were a little
chore. I still haven't found my reed switches, but I expect that will work.
The is my counter.
> https://www.dropbox.com/s/n2tx6mf6448d9by/counter.jpg?dl=0

Mikek

 

[amdx]

On 9/16/2019 10:38 AM, Jeff Liebermann wrote:

On Sun, 15 Sep 2019 18:45:05 -0500, amdx <nojunk@knology.net> wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

Sanity check. If you used a long-life mechanical microswitch, good
for a minimum of 50,000 cycles,
https://sten-eswitch-13110800-production.s3.amazonaws.com/system/asset/product_line/data_sheet/124/MS.pdf
at 330 revs per minute and one count per revolution, your switch will
be dead after:
50*10^3 / 330rpm = 151 minutes = 2.5hrs
If you believe the 1 million operations specification (I don't), it
might last up to:
1*10^6 / 330rmp = 3,000 minutes = 51 hrs
Be sure to have a box of replacement switches handy.

By coincidence, I recently bribed my auto mechanic with a tiny magnet
hall effect sensor tachometer for his lathe:
https://www.ebay.com/itm/4Digital-LED-Tachometer-RPM-Speed-Motor-Car-Meter-Proximity-Switch-Senso-US/323666797728
It won't count revolutions, but will measure RPM, which is what I
suspect you really want. I've used these on a drill press in the past
and found that contact cementing the tiny magnet to the spindle pulley
and installing the sensor between the pulleys works well.

The biggest problem was finding 12VDC near the drill press. I used a
common "wall wart" power supply because the owner didn't want me to
splice into the 117VAC power. Finding a good box was also problem.

You can also get photoelectric tachometer kits, similar to the hall
effect sensors. Gluing a reflecting piece of tape to the spindle
pulley or the belt should work.

Example:
https://www.homemadetools.net/forum/new-rpm-meter-shop-fox-drill-press-modidication-65530
More:
https://www.google.com/search?q=drill+press+tachometer&tbm=isch

Ya'll have convinced me. I need two coils about 400 turns each. I'm
going to hand wind them.
Mikek

 

[John Robertson]

On 2019/09/16 10:20 a.m., amdx wrote:

On 9/16/2019 11:11 AM, Jeff Liebermann wrote:
On Sun, 15 Sep 2019 19:46:18 -0500, amdx <nojunk@knology.net> wrote:

I have a Root Veeder counter all it needs is a pulse, I wanted the
project to be counting the turns on a coil, not developing a circuit to
make a pulse to drive the counter.

Thanks.  So now you disclose what you're trying to accomplish.  I
assumed you wanted a tachometer for the drill press.  So, use a hall
effect or photoelectric proximity sensor:
https://www.ebay.com/sch/i.html?_nkw=hall+effect+proximity+sensor
https://www.ebay.com/sch/i.html?_nkw=photoelectric+proximity+sensor

I'm not sure what you have from Veeder Root.  If it's marginal, look
for an industrial counter or "totalizer":
https://www.ebay.com/sch/i.html?_nkw=electronic+totalizer
https://www.grainger.com/category/electrical/industrial-controls-automation-and-machine-safety/industrial-automation/meters-counters-and-plc/counters



 Hi Jeff,
 This should be simple although the mounting mechanics were a little
chore. I still haven't found my reed switches, but I expect that will work.
 The is my counter.
https://www.dropbox.com/s/n2tx6mf6448d9by/counter.jpg?dl=0

                            Mikek

The coil says is is DC yet the wires don't appear to be colour coded, if
this counter does not have a diode across the leads you will destroy
your switch from back EMF.

John :-#(#

 

[George Herold]

On Sunday, September 15, 2019 at 7:45:07 PM UTC-4, amdx wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

You could do optical detection with a 1/2 moon disk, LED and photodiode.
Put more than one slot in the disk and you can do fractions of a turn.

(I didn't read the whole thread so someone may have suggested that already.)

George H.

 

[mpm]

On Sunday, September 15, 2019 at 7:45:07 PM UTC-4, amdx wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

Personally, I would not immediately elect to use a reed switch for this application. There are many better ways to do it, especially if you are comfortable programming up 8-bit micros, or even the new Arduino hobby-grade stuff. I would look at Hall Effect sensors, or something in optoelectronics. You could get rotational speed, a count, and even direction.

Good luck with the project.

 

[Phil Allison]

Jeff Liebermann wrote:

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

Sanity check. If you used a long-life mechanical microswitch, good
for a minimum of 50,000 cycles, at 330 revs per minute and one count
per revolution, your switch will be dead after:
50*10^3 / 330rpm = 151 minutes = 2.5hrs

** That seem realistic to me.

Recently had to relace my computer mouse cos a microswitch failed, the left click one IIRC.

Lasted about 5 years at say 50 operations per day.

So about 100,000 cycles.


..... Phil

 

On Monday, 16 September 2019 00:45:07 UTC+1, amdx wrote:

I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
It doesn't work. Unreliable counting.
My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

Mikek

I'm wondering if you need this bit of kit at all. If you know it does 330rpm, you know how long to run it for each desired winding. For just 5 or 10 turns you can turn it by hand.
.... unless you really do need 1 turn accuracy.

You might even find that a carbon brush & some thin insulation might suffice.


NT

 

[Rick C]

On Monday, September 16, 2019 at 9:21:43 AM UTC-4, amdx wrote:

On 9/15/2019 10:13 PM, Sylvia Else wrote:
On 16/09/2019 9:45 am, amdx wrote:
I wanted to make a turns counter for my drill press.
I have it set for 330 RPMs or about 6 cycles per second.
  It doesn't work. Unreliable counting.
  My high point is (switch closure time) about 1/12 of the rotation, I
wonder if I did a 50/50 duty cycle if it would be better.

Or, is expecting the switch to operate at 6Hz just to fast for a
standard microswitch?

                                  Mikek

How are you doing the counting?

Sylvia.

Veeder-Root counter, 12V 8 Watts.
I tried to post a Dropbox picture, lately the link in my Dropbox
window does not highlight to copy.
I had this problem then it started working, now having it again,
anyone else having Dropbox problems?

Mikek

Not trying to be a jerk, but I googled Veeder-Root and that doesn't tell us a lot. They also make electronic counters.

--

Rick C.

+- Get 2,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209

 

[Phil Allison]

Rick Cunt the Moron wrote:
--------------------------

** Nice unit but overkill.

The op only wants to count turns cos he is winding inductors.

His mechanical counter is fine,
it just needs a one cycle per rev switch to drive it.

Who gives a crap if it is overkill???

** Anyone who was sane ?

Mr C just has to be a code scribbler.

Bet he never got the chicken joke on BBT.



..... Phil