[2 days left] What’s wrong with your cloud strategy? Learn why multicloud solutions matter with Nimble Storage.Register Now


How to use a coin acceptor in VB

Posted on 2001-06-19
Medium Priority
Last Modified: 2010-05-02
I'm now working with a coin acceptor and the comm port.

Using this code i'm able to reciebe the pulses of the acceptor.

Private Sub MSComm1_OnComm()
    Select Case MSComm1.CommEvent
        Case comEvCD  
        msgbox "Pulse"

    End Select
end sub

but it fails with some pulses and don't works at 100% and i have to achieve that every pulse sent by the acceptor is triggered by my program.

I am using this code to initialize the serial port:
MSComm1.CommPort = 2
MSComm1.InputLen = 0
MSComm1.Handshaking = comNone
MSComm1.PortOpen = True

I need help about what are the correct parameters to program the Mscomm to receive/send pulses to the acceptor.

I have NO idea about comm programmming and i'm actualing searching info about that :)

Thanks in advance
Question by:MoriQuendi
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions

Accepted Solution

gbaren earned 1200 total points
ID: 6207657

Without handshaking, the events are not reliable. The device you are working with, probably does not support handshaking anyway.

The way to do this is to keep polling the InBufferCount property. When it becomes > 0, that means you had received that many pulses. You access the Input property to clear InBufferCount back to 0.

This should be done in a Timer control's Timer event.

Here's some code to try:

Option Explicit

Private Sub Form_Load()
    With MSComm1
        .CommPort = 1
        .Settings = "9600,n,8,1"
        .PortOpen = True
    End With
    With Timer1
        .Interval = 100 'poll every 100 milliseconds
        .Enabled = True
    End With
End Sub

Private Sub Timer1_Timer()

    Timer1.Enabled = False

    If MSComm1.InBufferCount > 0 Then
        MsgBox "Pulse with data: " & MSComm1.Input
    End If
    Timer1.Enabled = True

End Sub


Author Comment

ID: 6209501
Do you think is better to use a timer instead the OnComm event?

well i'll try :)

Author Comment

ID: 6209738
Do you think is better to use a timer instead the OnComm event?

well i'll try :)
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Expert Comment

ID: 6210352
If the OnComm event was more reliable, it would be better to use it. As it is, unfortunately, this is the best way. The MSComm control's OnComm event has never been reliable.

Expert Comment

ID: 6221902
I'd start looking at your hardware....the Comm port wants to see about +9 to +12 VDC as an "OFF" signal, and about -9 to -12 VDC as an "ON" signal. You might need to convert some voltage levels to improve the reliability.

I have been using the MSComm control in numerous projects for the last 6 years, and have not run into an OnEvents problem.

Hope this helps!

Author Comment

ID: 6223610
The coin acceptor is manufactured by Jofemar and works with 12V (i'm plugging the acceptor to the computer's power supply directly).

Is there any Comm propertie to take care about? or the default ones works with this device?

Author Comment

ID: 6289039
Sorry, i was out for two weeks ad i was unable to continue this task, expect my answer soon ;)

Expert Comment

ID: 6289620
Actually, are you sure this is a serial device? Sorry for the silly question, I just want to make sure you have a serial and not a contact closure device.

Author Comment

ID: 6316722
This device is not originally developed to be attached to a computer but it have to work.

It seems that it can be a hardware solution:


There's a device than check when the serial is working or not.

LVL 49

Expert Comment

ID: 7139522
Hi MoriQuendi,
It appears that you have forgotten this question. I will ask Community Support to close it unless you finalize it within 7 days. I will suggest to:

    Split points between: gbaren and kfrick

MoriQuendi, if you think your question was not answered at all or if you need help, you can simply post a new comment here.  Community Support moderators will follow up.

EXPERTS: If you disagree with that recommendation, please post an explanatory comment.
DanRollins -- EE database cleanup volunteer

Author Comment

ID: 7139879
I forgot this thread at all, sorry.

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Most everyone who has done any programming in VB6 knows that you can do something in code like Debug.Print MyVar and that when the program runs from the IDE, the value of MyVar will be displayed in the Immediate Window. Less well known is Debug.Asse…
Enums (shorthand for ‘enumerations’) are not often used by programmers but they can be quite valuable when they are.  What are they? An Enum is just a type of variable like a string or an Integer, but in this case one that you create that contains…
As developers, we are not limited to the functions provided by the VBA language. In addition, we can call the functions that are part of the Windows operating system. These functions are part of the Windows API (Application Programming Interface). U…
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
Suggested Courses

656 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question