Logical Circuit Switch

[rotator78]

Hi everyone!

I am new here in this forum and hoping that i came into the right place.

Basically, I'm having a problem with my project that's why i came here to ask for an help.

The concept of this project is to POWER ON/OFF a desktop computer using a Logical Circuit (monostable) Switch.

Here are the following gadgets to use:

1. A "coin slot acceptor" that produce signal going to a digital timer circuit board to activate time.
2. A "Digital Timer circuit with 3 digits 7segment display and a relay switch" that will be used as the source power of the Logical Circuit Switch.
3. A Desktop Computer with a tap/push button switch.


Now, i want to use the Logical circuit switch as the "tap/push switch" of a PC. In short, i want to make the switch from manual to an automatic time dependent switch.

If a user inserts a coin into Coin Slot Acceptor, the digital timer will start a set of time depends on the coin inserted by the user. Example, 1 coin is equivalent of 5 minutes and the users inserts 3 coins, the time will set to 15 minutes for the coins inserted.

The job of the Logical Circuit Switch will "TAP" once, upon starts of time and will tap "again" after time is up.

I know you guys know this type of circuit. I hope you will help me with this project...

Thank you in advance and more power!!!!

 

[neptune]

post circuit diagram

 

[carbonzit]

Sounds like you're building a pay computer kiosk or some such, correct?

Not to talk you out of your plan, but there might be other ways to do this. One problem is that people aren't going to be happy with minutes of their paid time going to waste while the computer boots up. So you might consider leaving the computer powered on all the time, but using the coin-operated timer to lock and unlock the computer. Lots of ways to do this: you could lock the keyboard, for instance, which would be a really crude way of doing it. Better would be to have the time switch interface to the computer (through one of its ports) and run a script that would log on and log off users and keep the computer from being used until someone puts some money in the coin slot.

 

[rotator78]

I don't have schematic diagram yet. If you guys have it, please send me a copy.

Its just only a project to make things possible.

Is there anybody knows the circuit here?

 

[alec_t]

There is no unique circuit to achieve what you want. Much will depend on the characteristics of the components you use, e.g. the output signal (pulse, DC level, polarity, frequency ??) of the coin detector etc.

 

[mbarazeen]

as i understand your basic requirement is to have the timer work perfectly, to down count the time based on number of coins inserted. also it has to increment the time by certain value when a coin is inserted before the time ends...... i think it need a micro processor based design with some arithmetic algorithm

hope some one can help...

 

[rotator78]

Yes. it needs a new circuit to act like tap switch. It will get source power from the relay out of the timer. Somebody gave me a monostable diagram but i didn't try it yet. It uses a logic gate (inverter), a LM555 ic, some diodes, resistors, and capacitors. The output is also a relay switch.

I want also to try an alternative method like using RS232 with a software, but i don't have any idea how to do it. I have a little background in programming using JAVA and VB.NET, but i haven't tried communicating like this gadgets without a driver softwares.

Does anyone have this one? Please share your knowledge to solve my project. Thanks!

 

[carbonzit]

This is actually a pretty interesting problem. The more I think about it, the more I think a hardware-software solution, using the computer itself, would be the best way to tackle this. You could use a separate microprocessor, but why? with a much more powerful computer sitting there.

In fact, you could reduce the coin-operated device to one simple function:

Tell the computer that someone put a coin in me.

Think about it: assuming the computer is up and running at all times, and monitoring the coin device, all it needs to know is when someone puts a coin in.

Based on its current state, it then decides what to do:

• If the machine is currently inactive (nobody's using it), start a new user session (log user on, etc.) and issue X minutes of time to the user
• If a user is active, add X minutes of time to their account

When the time expires, the user gets logged off and the computer is locked up. (As a courtesy to the user, it would be nice to alert them before this happens.)

Whoops, I forgot about your 3-digit display you said you wanted. Well, you could just chuck that, and use the computer itself to display the remaining time, in a corner of the screen, say.

So all your coin device needs to do is to send a signal over a port (serial, USB). The hardware could be extremely simple.

This also assumes minimal security. What kind of security requirements do you have? In other words, are you concerned about people trying to hack your system to steal time on it? Will it be running unattended, in a public place?

Anyhow, those are my current ideas.

 

[Reloadron]

I tend to agree with carbonzit on this in that a hardware / software solution would likely be a good choice. I do not see using the system On/Off push button as a viable solution for a number of reasons. I would not rule it out, I simply would not use that method.

The coin system would need to be interfaced to the computer and I don't see an interface of the parallel port or RS232 serial port as a viable interface. Both of them are slowly heading for extinction. Yes, computers can still be purchased or built with those ports but I don't see either as viable as they grow extinct. I would lean towards a USP port interface given a choice. That or an ethernet port with either using a wake on LAN function. Something along those lines for the interface.

While I am not a programmer type I would venture a guess that a software routine (program) could be written to allocate logged on time based on monies inserted into the external hardware. Possibly the application would run started from a RUN key in the registry. Thus when the system boots the application would be launched. That or scheduled to start at logon.

Ron

 

[rotator78]

Telling the computer what to do next is just easy to say, but in writing the code itself is a pretty complex thing.

I don't know where to connect (configure) the pulse signal from my coin selector to a RS232 or USB port. and also to write the code how to get the pulse signal from an RS232 or USB port. I think i will be using a rs232 circuit module to recognize my coin slot selector.

Does anybody tried coding it before? If somebody does, please post it here...

 

[Reloadron]

OK, let's try starting at the beginning. What does the output of the coin collection hardware look like? That will figure into the scheme of things. Never having worked with one I have no idea what they output. This is important as this determines how the code will be written. A data sheet on the collection system (hardware) would be nice to see. What is this pulse you mention?

As I pointed out, I am not a programmer but I don't see writing the code for some basic functions as being all that difficult or complex. I assume you have a compouter with a RS232 port? I also assume you are running a Windows based operating system? This begins with the coin collection device. I have written a few basic routines that will show you what the RS232 port is doing. I can link to it later but will make some changes to it to give you an idea or two. This will be done at home as I am at work right now.

Did you understand what I posted as to starting an application or program from the registry at boot?

Ron

Ron

 

[Brevor]

I worked for many years as a customer service engineer for couple of companies that manufactured coin and bill acceptors. We had some customers that were using our products for paid internet access. They used the serial data output from the currency acceptors to connect to the PC to enable access. Check if your coin acceptor has this type of output.

 

[carbonzit]

At this point, ASS-U-Ming the O.P. likes my overall idea (using the PC to run the code to handle the coin device), we have these unanswered questions:

1. What is the output of the coin device: a simple pulse or set of pulses? something more complex? what interface (2 wires, IEEE-488, etc.) does it use? (Don't worry; IEEE-488 is a joke.)

2. We still don't know what kind of security is required. How safe do you want to make this against possible attackers?

3. What would be the simplest, fastest-to-learn code "platform" to use? C? QuickBasic? .net? Javascript? something else?

My guess is that this will have something to do with the availability of existing standard libraries to handle input from [insert name of interface you'll use: USB, RS-232, etc.], so you don't have to reinvent this wheel.

You probably shouldn't have to muck about much with low-level code; that should be handled by a library, DLL, etc. You can just focus on the operational code, which will be pretty straightforward. (Well, plus any user-interface stuff, like displaying the remaining time on-screen.)

 

[rotator78]

This is the model of a coin selector that i will use

**broken link removed**

and the attached image is the digital timer.

 

[rotator78]

I worked for many years as a customer service engineer for couple of companies that manufactured coin and bill acceptors. We had some customers that were using our products for paid internet access. They used the serial data output from the currency acceptors to connect to the PC to enable access. Check if your coin acceptor has this type of output.

Do you know how they made it?

 

[Brevor]

Do you know how they made it?

The acceptor had a serial data output, it would output a data packet indicating what denomination it had accepted. This went to the serial port of a PC which ran a background program under Windows that enabled internet access for a set amount of time.

 

[Brevor]

I followed the link to the device you plan to use. In the coin op business that is called a rejector. (rejects slugs) Most likely it doesn't have a serial data output, probably just a pulse output, and only accepts one value of coin.
Sometimes customers that used these would connect the pulse output to an interface board that converted the pulse output to a data packet to connect to a "smart" machine.

 

[Reloadron]

I followed the link to the device you plan to use. In the coin op business that is called a rejector. (rejects slugs) Most likely it doesn't have a serial data output, probably just a pulse output, and only accepts one value of coin.
Sometimes customers that used these would connect the pulse output to an interface board that converted the pulse output to a data packet to connect to a "smart" machine.

I followed the link but can't read Chinese?

A friend of mine has one similar unit. Actually pretty neat. You place a coin inside it and it learns the coin. Then it will sort real from counterfeit coins as fast as you feed the thing. He uses it to sort US pennies for copper content. Anyway, I agree with Brevor that it just verifies if a coin is real or not.

As to the timer, what does it output? Meaning for example a logic high or low for a preset period?

Ron

 

[rotator78]

I guess that would be very complicated in my case. I really want to try that method, but it's really hard to find the gadgets. I don't think if that Serial Interface module is available here in our country. It might, but rare.

Does anybody have an any idea except turning OFF the monitor and locking the mouse and keyboard?

 

[rotator78]

As to the timer, what does it output? Meaning for example a logic high or low for a preset period?

The output of the timer is depend on what you will connect to the output relays.