Controlling Barcode scanner input

[ehanson]

I'm working on a program that uses barcode scanners as input. Right now, I'm using a USB-HID device scanner and I have to have focus on the application. From what I've read it seems like this is probably not the best option. Would I be better off using an RS232? If so is there code in Xbasic that will take control of the serial port?

[Al Buchholz]

Re: Controlling Barcode scanner input

a scanner is just keyboard input to Alpha.

[ehanson]

Re: Controlling Barcode scanner input

I want to program the serial port so that the Alpha 5 program interupts the data from the serial port. I know that the USB hid connection for a barcode reader is read like a keyboard input, but the serial port needs additional programming and is able to be manipulated. There is Windows API's for this, but all are in C#, C++, VB.... What I was wandering is if Xbasic has a way of using these COMM Interupts.

[martinwcole]

Re: Controlling Barcode scanner input

We use barcode readers a LOT
and we use usb devices
in our scenario, the user clicks on a box, and scans which fires the onchange event for that object

its very easy, and very simple

if you want to use a scanner with Alpha then there will have to be a form with an object for receiving the input with code for processing it

you can also put code in the onkey event of a form, and read the results and trap for a scanner entry - in fact Ira Perlow has a function he wrote for sale for using with the onkey event of a form

[Ray in Capetown]

Re: Controlling Barcode scanner input

a scanner is just keyboard input to Alpha.

Is true ONLY at the high level of Windows (or other OS) to USB interfacing.
I guess that native Xbasic would have commands, but I dont know them. They would probably, if memory serves, be something like "Open COM1, baud, parity, stop bits" - in any event, if I right now, with no knowledge of connecting high level to low level programming, was faced with the problem of requiring that level of control, would take the following approach;-
Use Xbasic to run a command program (.BAT file, my first choice) or a write a C program (.EXE)
These commands would be to

1. first open the COMn Port with the hardware specified baud rate, parity and stop-bits.
2. Wait for input. (your standard hardware interrupts for COMn will do this)
3. Write the bytes input to a .TXT file.
4. Close

This returns control to Xbasic,

1. read the characters from the .TXT file
   
2. Clear/delete the .TXT file
3. Do what you need with the characters

All Without requiring focus to an input field


If you need further help, explain the situation - eg data capture or whatever and give me a bit of time to mix it up i will try give you the code for the BAT file.

OR ask one of the few people in the world who can write low level Xbasic, like Selwyn I suspect.

Ray

[ehanson]

Re: Controlling Barcode scanner input

Thank you Ray in Capetown. I have my program right now set up with all of the onkey events and trapping mentioned in the other posts, but my problem is there is still too much room for error because the program I'm working on will be running in the background and there will not be a user on th computer. If for whatever reason Alpha 5 loses focus on the machine we would lose the input until I caught it. I have API's for COM Interupts, but I don'tknow how to use them in Xbasic. My only real complaint about Alpha 5 is that you have to use Xbasic programming language and can't use languanges like C#, C++..... I think that I remeber hearing that you can use other Methods and API's from other languages by referencing the dll file, but I'm not sure how. My other option is to use a Virtual Machine that takes control of the USB port and only has the program I'm using running on it, but they take up a lot of RAM from the host computer. If you could help point me in the right direction on how to use an API from a different programming language I would greatly appreciate it.

[Ray in Capetown]

Re: Controlling Barcode scanner input

My other option is to use a Virtual Machine that takes control of the USB port and only has the program I'm using running on it, but they take up a lot of RAM from the host computer. If you could help point me in the right direction on how to use an API from a different programming language I would greatly appreciate it.

Separate the data reading from the processing.
1. A relatively simple, minimal overhead program captures readings from a scanner into a file.
2. Xbasic in A5 can, as required, collect and process. This is easy.

Use a serial port scanner. The COM port is perfect, underutilized, always listening and simple for a dedicated task. The low level software would survive any Windows program crash, except for a reboot.
I could not write the code for the first step blind, I would need to have the hardware, test each line of code and the resulting table ... maybe the device issues CR/LF, it may require hardware handshaking etc.
The same could be done with USB but the resident software would be more sophisticated.
The vendor may be your best source.

[Clunes]

Re: Controlling Barcode scanner input

A usb scanner is so cheap. seems to me you are going to a lot of time and effort that about $30 will get rid of

[martinwcole]

Re: Controlling Barcode scanner input

I agree with Clunes - if you are going to use the barcode scanner with an open Alpha program, a simple USB scanner is perfect. If you are trying to connect it with other software, then that's another story. One of my clients has about 17 of them, and scans a workorder when it is received and completed. To get around having to have the user on a particular object on the screen, you can use the onkey event to trap the scanner, and based on the form, do stuff.