Help for PIC to PC RF Link

[happy_99]

Hi

I need to connect my PIC project board to my PC using RF link. For that I'm looking for a good transmitter & receiver circuit. Pls I need help..

Thank You.

 

[ssssss]

Try Linx modules I think they are good to make a quick RF link, they come in several frequencies VHF, 900MHZ etc.

 

[happy_99]

thanks..but I'm looking for the schematics..

thank you

 

[ssssss]

Try this:

**broken link removed**

 

[happy_99]

The AN# is a useful one..But looking for the schematics of the Tx & Rx. I need to build it myself !

Thank You

 

[Fragrance]

hi friend


I personly i used wireless mouse (Rf ) very cheap to get the following features.

1) the Transmiter based on saw resonator provide very stable frqeuncy
2) Receiver is based on super hytrodyne principle and crystal controlled
for extra power i add a small rf amplifier to increase the range


work very fine with out any problem also see the link

[web]hxxp://www.rfsolutions.co.uk[/web]

 

[benradu]

Micrel (www.micrel.com) produces some AM transmiters and receivers. Another very good solution are nRF chips from Nordic VLSI (www.nvlsi.no).
Both of them gives you schematics, AN's and they have good support too.

 

[asena]

You may also want to check Chipcon RF CMOS chips.

www.chipcon.com


asena 8)

 

[tgq]

look at this
**broken link removed**
not a professional schematic :? but maybe u can have fun with

 

[abb652]

Here you have the TX and the RX circuit.
It works fine in a distance of 30 meters and 2400bps.

If you need more distance and more speed, you can use the TRF6900 for TI.

 

[happy_99]

It's really a very good document. I would like to know what's the max supported speed. I require a speed betn 4800-9600bps.

thank you

happy_99

Here you have the TX and the RX circuit.
It works fine in a distance of 30 meters and 2400bps.

If you need more distance and more speed, you can use the TRF6900 for TI.

 

[abb652]

I don´t know the max speed of this circuit, but i suppose that it works at 9600bps.
I used it at 2400bps.

Many commercial transceivers use this circuit.

I recommend you to implement some kind of protocol instead of transmiting raw data in order to avoid interferece. That is because some Car Alarm Remotes uses this band (and sometimes this circuit).

Regards

 

[happy_99]

I need help for the Tx circuit. Could you pls give the values of the parts used and the spec. of L1.

thank you

happy_99

 

[abb652]

Sorry!!!

Best achievable performance occurs when the ground of the SAW device, C2 and C3, are physically close, preferably a single point on the
PCB. Transistor selection may be the BFS-17A, MMBR-901, MMBTH-10LT1, MMBTH-17LT1 or similar
NPN Silicon transistor.
C1 = 1 to 5pF, C2 = 8.2 to 18 pF and L1 selected/designed to resonate with the series combination of C1 and C2.
Best is C1 = 3.3pF and C2 variable from 5 to 30pF, L1 = 1 turn, 1 cm air core, 18awg wire.

Values for Rb = 100 Kohm and Rc = 47 ohm, Resistor Re = 470 ohm.

In most cases, you must adjust this values.

Attached is another TX circuit.

Regards