Tag: counter

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High speed counter and Encoder reader

We are getting ready to release a new high speed counter that greatly simplifies machine to PC connections. 

Feature set:

  • Read quadrature encoder pulses at up to a 20MHz rate.
  • Single-ended or differential pulse inputs.
  • USB data output provides count to USB or encoder to USB output.
  • USB connection for configuration.

The device implements USB counter that is significantly faster than our existing ones and it is still compatible with the existing software interface.
This counter has a maximum input pulse rate of 20MHz and will accept either a “standard” or Gray-code mode used for interfacing with quadrature encoders. You can now get a high speed quadrature encoder input read from your PC’s USB port. This new high speed interface is available in a choice of DIN-rail mount or standard wall/desktop mounting enclosure.

Click the link below to be notified when the interface is available for the introductory $125 pricing. This price is only available for pre-orders.



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Sensor for detecting thin lines

A few months ago I was asked to build a custom counter. I get that request fairly often, but this one was different. The thing that needed to be counted was the transition of a thin line past the sensor. The feature to be counted was about 0.5mm thick. It was a black line on a yellow background so at least the contrast was pretty good. Since the counter needed to be portable and could not be attached to the equipment containing the feature to be counted, we figured that a way to visually align the sensor to the line was best. This meant that the sensor would emit visible light, so it would be possible to see when the light was in the right spot.

Since a 0.5 thin line is in the realm of barcode line decoding, I looked for sensors used in barcode readers. Problem is, that they are rarely specified that way. All I could find were 2D barcode sensors/cameras and those were overkill for my purpose. Oh, well!

So I figured that what made the most sense was a sensor with a small field of view. That way it could provide the highest signal to noise ratio (SNR).

I tried a number of sensors but the one that offered the best performance was the Optek OPB70DWZ. Having a red LED meant it was easy to tell when it was correctly positioned to “see” the feature. We found that the optimal distance from sensor to object was about 4mm. At that distance it worked quite reliably. The sensor was biased with a 4.7k ohm resistor to +5V. I found that by varying the bias, I could affect the sensitivity and adjust it for best SNR.

The counter itself had some logic to control the machine whose behavior was being counted, and it also required a display to show the count and to indicate what the current machine state was, so I did not use one of our existing RS232 counters. Instead I created a custom application based on an Arduino Nano and it’s worked quite well. The customer appears quite pleased with its performance.

The usual disclaimer: we’re not affiliated with Optek, but very happy with the performance. I’m posting this here because when looking for an optical sensor that could detect very small features or lines, nothing useful was returned from my searches. Hopefully this helps someone in the future.



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Categories
Arduino

Connect bill acceptor or coin acceptor to PC

One interesting application for our PRT232 pulse counter is reading bill acceptors and coin acceptors from a desktop computer.

A coin acceptor is used to pay for a product or service. You’re probably quite familiar with them from using commercial laundry machines or video game arcades. In these situations, they are built into the equipment. However we are seeing an increase in cases where someone is adding a payment facility via a bill acceptor or a coin acceptor to equipment that was not designed for it. An example would be a kiosk that dispenses water. There are many of these in grocery stores where you can fill up your bottle with pure water and then pay for it at the counter. But many entrepreneurs are taking water dispensers and making it possible for the customer to pay directly at the point of sale.

These acceptors work by sending a number of pulses corresponding to the coin or bill that is entered. e.g., a quarter may provide a single pulse while a dollar bill gives four pulses. Our pulse counting devices are obviously a natural fit for the application. They will accept the pulse output from the coin acceptor, count the pulses and provide a  serial RS232  interface to the PC making it simple to tally the dollar amount entered.

By using a counter to RS232 device like our PRT232 or PRT232F (6 count inputs), now the PC computer can be used to track usage, make automated daily reports, provide the customer enhanced user interface and so improve your sales performance.

We provide a sample of software that uses the PRT232 as a dispense controller. It can be easily modified for your own use. We also offer custom software and hardware development in this area.

One example of what we have done is the situation when the bill acceptor must be connected to a machine that doesn’t correspond exactly with its operation. For example, perhaps you are building a vacuum cleaner that the operator pays to use (as often found at a car wash). The vacuum may have been designed to start with a contact closure, but in order to use your coin acceptor, you must translate the four pulses from four quarters being deposited into a single output. We have designed electronics to solve exactly this situation. If you need something similar, contact us.

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