Wireless Project

[nikhil_s]

Hello everyone, I am trying to build a circuit that will allow 2 PC's to communicate wirelessly to fulfill the requirements of a communication course. I am in my junior year of a BS program in Electronics and Communication. I intend to use the RS232-DB9 serial port. I need help in this regard.

My problem Definition is as follows:
1. PC A generates some data. (Text/ASCII chars) It is output through its serial port by using a C program.
2. This data then needs to be sent to an RF module that modulates the data bits using a modulation scheme (like FSK) and transmits it.
3. It is received by another RF module, which then hands over the data to PC B.

Here are a few questions I have:

1. Do we need MAX232 Line drivers and a microcontroller (for what function) to interface between the PC and the RF module? (I am acquainted with programming of the 8051)

2. Does circuit complexity increase drastically if we implement in Full Duplex? (Currently considering MT8870D or MT8888C)

3. How would one go about doing the PCB layout...does anyone have relevant schematics with layouts and circuit details?

Thanks for your time….

 

[Nigel Goodwin]

1. Do we need MAX232 Line drivers and a microcontroller (for what function) to interface between the PC and the RF module? (I am acquainted with programming of the 8051)

You need to convert from the +/-12V signal levels of RS232 to a logic level, a MAX232 is a common way of doing so - although there are many others, some of which are far simpler and cheaper.

A uP is a good idea, as it allows you to go the required coding and encoding - the usual method used is Manchester coding.

2. Does circuit complexity increase drastically if we implement in Full Duplex? (Currently considering MT8870D or MT8888C)

Yes, to some extent, for full duplex you require two transceivers on different frequencies (usually on different bands), so one can transmit while another receives.

3. How would one go about doing the PCB layout...does anyone have relevant schematics with layouts and circuit details?

Check the datasheets for the manufacturer of the RF modules, you will also find that such RS232 RF modules are available ready built - and you might find it useful to study their specs?.

 

[crowinu]

1. Do we need MAX232 Line drivers and a microcontroller (for what function) to interface between the PC and the RF module? (I am acquainted with programming of the 8051)

You need to convert from the +/-12V signal levels of RS232 to a logic level, a MAX232 is a common way of doing so - although there are many others, some of which are far simpler and cheaper.

A uP is a good idea, as it allows you to go the required coding and encoding - the usual method used is Manchester coding.

2. Does circuit complexity increase drastically if we implement in Full Duplex? (Currently considering MT8870D or MT8888C)

Yes, to some extent, for full duplex you require two transceivers on different frequencies (usually on different bands), so one can transmit while another receives.

3. How would one go about doing the PCB layout...does anyone have relevant schematics with layouts and circuit details?

Check the datasheets for the manufacturer of the RF modules, you will also find that such RS232 RF modules are available ready built - and you might find it useful to study their specs?.

try the rfsolutions ready built RF trancievers [RF650 - 433MHz Transceiver Module], Some features : Serial Packet Data Rates up to 19.2Kb/s, 200 Metre Line of Sight Range, RS232 Serial Data Protocol, Logic level Interface

crowinu