I dunno if this goes here, but never mind.

Using RF serial link to connvect RFID receiver to PC

I dunno if this goes here, but never mind.

I have a RFID receiver that is connected to a PC thru a RS232 to USB converter cable. Now, what I wanna do is to take out the cable and replace the connection with a wireless RF one..

I've asked around and I think what I need is a RF serial link. Yeah, I know there are serial links being sold online, but if possible I want to create my own circuit for this.

Any suggestions?

BTW it's just a one-way communication between the RFID receiver and the PC to send the ID that's all.

The most important question is whether the RS232 link is in one direction or both?

Does the RFID reader just throw out the tag ID when it sees a tag, or does the PC have to ask for it?

If it is one direction, you can put a transmitter on the RFID reader and a receiver on the RS232 - USB converter.

If it is two directions, you could use two frequencies, one for each direction.

Or you could have a microcontroller that asks the RFID reader for the tag ID, and transmits the reply by wireless to another microcontroller. The second microcontroller is connected to the RS232 - USB converter and pretends to be the tag reader, and replies to the PC with the tag numbers.

The RS232 is receiving message from one direction. There is input from the RFID reader straight to the computer, thru the RS232-USB converter cable.

When I tested the RFID, it just displays the tag ID, no need for verification. The same also happens when there are two or more RFID tags.

Is there any way that I can implement this using a schematic that doesn't require any microcontrollers? Because if possible I want to keep this as simple as possible.

Then again, if I have no choice but to use them, does anyone have the schematics? I've tried searching on the internet, but I dunno if the ones I got are the ones I need for this project.

I'll post the links that I've got later. The internet here is lousy right now.

You might be able to get a TTL wireless serial module (its like $5 for each TX and RX- so $10 total)

Have serial output from your RFID level converted to TTL levels, and then sent to the wireless module. Once the receiver receives the information, level up to +/- 12 V (unless your RS232-USB converter can take TTL levels as well.

Everything after that should be the same.

If i want to convert the RFID to TTL, do I need any kind of programming?

Anyway, I got this link from the net **broken link removed**
and Simple RF Wireless Link | uC Hobby
Can I implement the project using this?

For level converting you do not. I think maxim makes rs232 level converters and they come in dip packages. I used to use MAX232 but I hear that its been discontinued and been replaced with something else (don't know what the part number is tho)

And as for that link, that's pretty much what I was saying, but you don't even need the microcontroller in this case.

RS232out --> level converter to TTL --> transmitter ---->wireless stuff---->receiver --> (maybe need to level it back up to +/- 12)---> rs232-usb adapter--> pc --> beer

You can't just feed TTL levels into a transmitter unless the transmitter has additional circuitry to convert the serial into a transmittable code such as Manchester encoding. Have a look at these modules as they do have the additional circuitry required and are relatively inexpensive.

Mike.

He's right. I forgot about that. It's been a while since I used this modules.

I don't think I can get those modules. At best I'm only gonna get a pair of these.

Cytron Technologies - Robot . Head to Toe : PIC Training Malaysia, PIC Microcontroller

For the level converter, do I need to use MAX232 or just some other circuit?