I dunno if this goes here, but never mind.

[Sodrohu]

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.

 

[Diver300]

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.

 

[Sodrohu]

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.

 

[tresca]

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.

 

[Sodrohu]

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?

 

[tresca]

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

 

[Pommie]

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.

 

[tresca]

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

 

[Sodrohu]

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?