Who gives a crap if it is overkill??? The Veeder-Root counter is crap if he can't make it work. The easy solution is to not focus on fixing the counter interface, but to just get it done by spending a very few bucks on a solution that *will* work.
I haven't finished the thread, but I haven't heard a solution that anyone is sure will work with this counter because no one is certain what is wrong.
-- Rick C. -- Get 2,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
I would think you want to minimize the mass of the offset weight, so a little shiny foil seems better than a magnet or a mirror.
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That's an idea. A small wire brush can be held tangentially against a smoo th part of the drill shaft or even a pulley, if it isn't the type that the belts are moved to adjust the speed. A bit of tape to hold a piece of plas tic (don't put the tape where it will be under the wiper) and you have a re asonable contact sensor.
-- Rick C. -+ Get 2,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
otation, I
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
rotation, I
us a lot. They also make electronic counters.
Appearance & specs very much suggest that it's a solenoid operated mechanic al counter. If so it won't give a wotsit about a bit of switch bounce. Ther e's no guarantee it will manage 6 operations a second though.
You could just use a cassette deck tape counter & belt.
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ooth part of the drill shaft or even a pulley, if it isn't the type that th e belts are moved to adjust the speed. A bit of tape to hold a piece of pl astic (don't put the tape where it will be under the wiper) and you have a reasonable contact sensor.
or two parallel strips of metal that gets pushed together by a cam
The probable cause of a mouse switch failure is... dirt. I've seen lots of (floppy insert, mainly) switches fail, that could be brought back with a few cycles of turning a light bulb on/off. That's because the low voltages that power a mouse (or floppy drive) are not going to burn through even a very thin film of oil/dust/schmutz.
At 24V, or with high currents, the flexible parts of a microswitch are good ... nearly forever.
Reed switches, with modest currents, are good for industrial controls such as this, with logic level voltages.
Remember cam actuated timers? Something like nightmare from my past: The really cheap synchronous motor drives would fail before the microswitches. However, if I replaced the motor, the switches would be the next to fail. If the contacts had over 1A DC or any inductive load, the contacts would burn or weld them at about 10,000 cycles. With AC, the contacts lasted longer. I used to do "industrial control" systems before the days of PLC controllers. Everything was relay logic and all the timers were these cam actuated nightmares. Cleaning moldy decomposed fruit and vegetable yuck from the mechanism was not my idea of fun.
"If it moves, it breaks".
Sounds about right. I see quite a few mice in my shop with switch failures. So, I went unto eBay, and bought an assortment of different mouse switches. When one switch goes bad, I also replace the other one or two so that all the buttons feel the same. However, the switch is not always the problem. The plastic "post" that pushes on the microswitch sometimes gets mashed or worn down, producing insufficient pressure to close the microswitch. For commodity mice, it's not worth my time fixing something that could be replaced for under $5.
However, gaming mice are a different story. Some of these mice sell for well over $100. I somehow developed a local reputation for fixing gaming mice and get enough business from gamers to justify a small inventory of replacement microswitches. However, with gamers, contact failure is not the problem. Gamers are rather brutal to mice and keyboards. I see mostly cracked switches, cracked PCB's, shredded cords, mashed connectors, and food debris jamming the mechanics. I doubt is the average gaming mouse would last long enough for contact failure to be a problem.
-- 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
Nothing is simple. Complexity is symptom of civilization.
Retch. Pure mechanical. I can't read the model number from your photo (because it's otto focus) so I can't dig for the specs. My guess(tm) is that it's a gear drive, driven by a solenoid and ratchet. The ratchet mechanism makes it really slow. I doubt you could get more than 1 count per second out of it. Got a square wave generator and a power xsistor? Try feeding it a 50% duty cycle square wave and increase the frequency until it starts to miss the count.
-- 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
Looks like an electromechanical device. It's entirely possible that it is not designed to handle a 6Hz rate.
As others have suggested, you probably need an optical/magnetic and electronic solution to get this to work reliably.
Sylvia.
I've run a solenoid-ratchet counter at 50 counts per second (but it said it was capable of this on the boilerplate)
Amdx's counter has the appearance of being an older device than the one I had. It looks Art-Deco, so possibly designed in the 1930s.
However it could be that it just needs a clean and re-lubrication to restore its performance.
-- When I tried casting out nines I made a hash of it.
looks kind of like this one:
That one does 1000 counts per minute so it should work at 360 rpm, but that number also implies that a 30ms pulse width may be needed, which your 1/12 dwell ratio may not reach. OTOH your DC counter may have a faster mechanism as it doen't need to operate from AC, so no shading rings etc.
-- When I tried casting out nines I made a hash of it.
I suppose if the OP rigged up his drill press with a generously forgiving cam (even an eccentrically-mounted circular collar around the quill would work if it were machined sufficiently smoothly for the uswitch lever and would probably not need de-bouncing. But that's still sub-optimal. I still think the laser-photodiode approach is best, but as modified by the chap who suggested reflective tape in place of the mirror.
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I think you might need to figure out what voltage, pulse length and current your counter needs to count reliably. Then you can put a one shot 555 on the output of your raw contact output to provide it. This will also debounce the noisy switch contacts in the process.
You might be better off with a pulley and a classic rotating wheels mechanical counter with a reset lever for what you are wanting to do.
-- Regards, Martin Brown
** I just tried a common micro-switch, the kind with a metal actuator and small wheel on the end.
" Cherry Elect. E33 10A 1/2HP 125-250VAC "
With a battery powered drill and using the small bumps on the rubber grip around the chuck to move the actuator up and down - I easily got it to operate at over 60Hz.
A 12V supply with 100 ohm resistor and the switch all in series produced an output signal close to square shaped that I viewed on a scope.
Conclusion: your mechanical counter is not up to the job.
Get yourself an electronic one.
For the little bit of work you need to do, a micro-switch will last long enough.
.... Phil
I may make another attempt, although I think I will use my battery powered drill. Connecting it to a variable power supply through a foot switch. Running my drill press at 330 RPMs (slowest speed) is a little fast and with the foot switch start and stop is kinda jerky. With the variable power supply I can set the speed. Somewhere around here I have a PWM circuit I built and used when I wound a 40 inch x 8" coil with 800 turns, (tesla coil) I made a couple of bobbins and winding form last night, I need to varnish the bobbins and then however I do it, it's ready to wind. Mikek
On Tue, 17 Sep 2019 04:43:03 -0000 (UTC), Jasen Betts wrote:
Here's a few of mechanical counters, where the usual measure of performance is in counts per minutes, not seconds: Typical is 500 counts/minute (8.3 Hz). One claims 3000 counts/minutes (50 Hz). Veeder-Root makes a high-speed model that will do 6000 counts/minute (100 Hz). So, you might be right about the speed, at least with high-speed maniacal counters.
In the early 1960's, the choices for radiation event counting was either one of these mechanical counters or a neon lamp ring counter. The mechanical counters would miss counts that were too closely spaced, while the ring counters would false trigger. For important experiments, both were used at the same time and the average of the two wrong numbers was decreed to be accurate. To keep me out of the way and busy, I was given the task of cleaning and oiling the mechanical counters. Most were Veeder-Root, similar to the one in question. Many were full of metal, plastic, or Bakelite shavings from the ratchet pawl acting much like a chisel. I lightened the spring tension and buried the mechanism in light grease. Performance improved, closing the gap between the mechanical and ring counters. Someone noticed, and allowed me to continue my tinkering in the hope that I could make further improvements. Nope. I only found ways to make things worse. For example, one grease I tried turned to tar when cold causing the ratchet pawl to slide over the gear. I did make minor improvements by polishing the ratchet teeth and tweaking the profile. Not bad for a 15 year old. I don't recall the performance numbers, but I think my mechanical hot-rod counters were able to do about 1,000 counts/minute. When the lab switched from Geiger tubes to scintillation counters, the count rate went higher than the mechanical counters could handle, so the mechanical counters were relegated to the junk pile.
-- 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
Might be OK if the cam gave a 50% duty cycle... not 1/12.
I've spent a few hours with a coil winder (old type, with a variac) and the easy way to do it nowadays is to get a stepper motor, and display with a microprocessor system of some sort. It wouldn't take much ( a stamp Arduino).
Four power transistors to drive a six-wire stepper, software to accelerate/decelerate and give continuous speed control (handy when the wire tension has to be managed) and make the turns count a presettable quantity. Go ahead and wire a potentiometer to a voltage-converting input for the speed adjust, and a second pot can set the terminal count (just use a few zoned voltages; midpoint it locks, half-CW it upticks slow, full-CW it upticks fast... like setting an alarm clock).
Two-line alphanumeric display for status won't take many IO lines.
Probably some hobbyist has already done it, and there's a 'sketch'.
Yep, sure enough:
For extra points, sacrifice a thrift-store battery drill to get gears and a chuck for the drive end.
-------------------
** See what happens when you "plonk" a serious poster. ------------------------------------------------------ ** I just tried a common micro-switch, the kind with a metal actuator and small wheel on the end." Cherry Elect. E33 10A 1/2HP 125-250VAC "
With a battery powered drill and using the small bumps on the rubber grip around the chuck to move the actuator up and down - I easily got it to operate at over 60Hz.
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.... Phil
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