counting bottles

see the engineer who maintains the conveyor (and other plant), there's all sorts of different resetable counting mechanisms available, he may even have a used one you can have cheap.

If you want to do it yourself consider attaching an light-beam sensor to an electronic counter. (maybe a cheap pedometer could be modiified?)

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Bye.
   Jasen

Hi, David. Even if you're paying yourself less than minimum wage and parts were free, you couldn't make a counter for less than you can buy one. And almost all of them have a reset feature either built into the front of the display, or have provision to attach an external switch for reset.

The sensing part is a little more difficult. If your milk bottles are full, it should be fairly easy to insert one of those microswitches with lever activators in line, and then use the contact closure to increment the counter. If that's not practical, there are many photoelectric switches that can sense whan the beam is broken and give an electrical output. The downside to that is that you'll need a separate power supply for the sensor. But many counters have built-in power supplies for external sensors, too.

Now, if the bottles are not filled, and are transparent, and you can't use a microswitch, you might have more problems. The photoelectric eye sometimes is not reliably switched by clear glass or clear plastic.

Your question is so general, it's kind of difficult to give a good answer without writing a book. Why don't you take the time to describe your problem a little better, and possibly someone can then give you a more specific answer. Please include:

• Number of counts per second, including how long the microswitch would be closed or the eye would be triggered.

• Possible to use a microswitch?

• Milk bottles full?

• If milk bottles empty, then glass or plastic? Glass/plastic transparent, translucent, opaque? If transparent, opaque to infrared?

• Is this just a school class question? You'll get a lot more useful of an answer if you just 'fess up. Nearly all dairies are fiercely automated, and this actually sounds more like a ringer question.

Good luck Chris

Thanks for the reply Genuine question this. We have a small on farm dairy we set up last year. Just seeking guidance on whether something is available off the self or we need to aquire components. We have full poly bottles

1 every 2 seconds should be possible to fix a microswitch to the conveyor guide rails DB

david b schreef in berichtnieuws snipped-for-privacy@i39g2000cwa.googlegroups.com...

Hello David,

A simple light-beam door-opener sensor you can buy everywhere connected to a as simple mechanical push-to-reset pulse-counter perhaps ?

Regards, Rudy Wieser

Hi, David. Just asking to get an idea of what you needed.

If you can work out a mechanical setup to sense the bottles, your job has become much easier and less expensive. Some microswitches (trademarked name, they're made by many suppliers) have rather long vane actuators at their ends which can be depressed by the bottles going by. This has the real advantage of greatest simplicity, but you have to make sure product goes only one way on the conveyor. On some of the long vane actuators, you can bend the end back to give it a roller effect. But be sure to get one that's rated for dry contact switching. You're going to be switching a low voltage at a low current. If you use a standard microswitch, the contacts will oxidize over time and become unreliable long before end of life.

As I mentioned before, it's far easier and more efficient just to purchase a counter module than to make one. There are many of these available which will work for you.

Unless you want a big display, you can go with one that's self-powered (e.g. a 3V replaceable lithium battery that should last for years). You need to specify one that has contact actuation (for your microswitch normally open contacts), and that has either provision for an external reset button or one built-in on the front display of the counter, or both. The contact activation part is critical -- if you get one that's voltage-actuated, the contact bounce of the microswitch will lead to multiple counts per bottle, especially as the microswitch contacts get old.

One provision I hadn't taken into consideration is that your electronics may need to be rated for washdown, seeing as this is a food handling environment. This is going to increase your costs by quite a bit, and may require you to get a switch with the appropriate food handling rating. Many of these counters come with a mountable silicone rubber boot you can put over the front of the display, which will give you the appropriate rating.

But if you don't have to be washdown rated, you can easily get the whole thing done for less than $40 USD for a new microswitch and a new counter. You also might want to ask around in your maintenance department -- they're typically pack rats, and may have the components waiting in a locker or drawer for you to pick them up.

I'm not familiar with too many distributor sources in the UK, but you could do worse than getting an Omron H7EC-N at Farnell (3262807) for =A335.02 in stock. A little pricey, but it's got everything you need for a washdown environment except the microswitch. It's got contact switching (set the DIP switch for 30Hz max), a reset button on the front panel as well as provision for external count, and it's also able to be hosed down if needed. Be sure to use the provided mounting kit, and use an approved gasket for mounting to a washdown box if you need it.

Good luck Chris

Many thanks for the advice, much appreciated. Will get onto it later this week David