I need help on a project urgently.

hello,

I need to carry out a project. the project involves a simultaneous fire detection and burlar detection circuits for various points. These circuits would be linked to a logic circuit and then would generate signals codes which would be transmitted and sent through a wireless link to a receiver then to a logic circuit for decoding and then to a pc.


Now the problems are as follows

1. I really do not know how to interface the signals received to a pc
2. I need a circuit of the transmitter and receiver of the digital signals that would be generated .
3. I would need to write a program for the pc to understand an interprete the codes sent, and determine what area is being affected.


for now these are the problems i think i would experience, any concerns,suggestions, daigrams .... would be highly appreciated.

Thanks
001,

Just one question:
Do you need one single unit to access several sensors, and then communicate with a PC over wireless LAN?

If you are planning to design something yourself, I would suggest search google for wireless USB modules. And purchase one or 2.

Buy a couple of FTDI 245, USB modules (from https://www.mouser.com/) for your fire detection you can use comparators and connect the output of the comparator to one of the i/o pins of the USB module. You can have up to 8 modules without any problem.

Then, you use the SW and the driver that is freely available from FTDI, and write a small program in C or VB on top of that and you are ready to go.

I am not sure of your professor will accept this as a project for the 4th year (I would deffinitly not do so), but this can give you an idea how you can do it.

Even easier, if you do not want to do any HW job, then buy a labjack USB module https://www.labjack.com/ connect it to the wireless USB and write your own code to capture the data and handle the informaiton, it is a quick and dirty solution.

I am nost if I was so helpfull, but just some crazy ideas,

BR,
/Farhad

001 said:

hello,
1. I really do not know how to interface the signals received to a pc

Click to expand...

everything you are asking is vastly, vastly very broad.
Explain more for what are you looking,:

a) What signals?
b) Power of these signals?
--- very important for government regulations and entire design of circuit
c) What bandwidth expetation or better how much information will be carried from these signals?
--- precisely how much information is really needed to decide a true decision for detection

Then this would be a starting point.

Thanks,

Actually, the signals I want to send are digital signals. The range would be between 1-2KM. I would be sending about 8 bits(1 byte) and the power of the signal would depend on the transmitter used. For now, I am concentration on designing the logic of the project. I was hopiing to get a circuit diagram for a transmitter and receiver for sending digital signals.

001 :? :?

Hi 001,
Depending on how much data you need to transmit, you can f ind a lot of different radio interface ICs on the market.

Since your transmission distance is pretty high, then you need to look into the devices that support your requirments.

One such family is the RadioWire family of products from Micrel.

**broken link removed**

According to their specification, the max range of the devices is 2 miles ca 3.2 km which is perfecf for your application.

The maximum communication speed for them is between 100-200kbaud.

They have modules in case you just want to test the idea before designing your own module.

Ther are other companies selling similar components, but most of them are for shorter range (up to 300m) or following the ZigBee standard.

BR,
/Farhad

it's a sensor.I think it'll not be complex.

Hello 001

I think that you are designing your own project .. so you have to design

1 - the the sensors scanner
2 - convert the analog values into digital
3 - send the data you got and the address of the sensor serially
(UARTmode)
4 - modulate the data using FSK modulation (such as in PC modem)
5 - so you can send this modulated signal using simple FM transmitter
6 - now receive the signal by FM receiver (Radio for Example)
7 - demodulate the FSK signal using FSK decoder (available as chip
XR-2211) and then you'll obtain the serial data again .
8 - enter this serial data into MAX232 and then the data will be ready to
enter the PC which will read the data of each sensor and send the
control command to the other circuits

note : steps 1,2 and 3 can be made by AVR micro controller

is this your what you want ?

Hello,

farhada wrote

Ther are other companies selling similar components, but most of them are for shorter range (up to 300m) or following the ZigBee standard.

Click to expand...

i think i would rather use a transmission distance of about 300m. Which you suggested.

Baslan wrote

modulate the data using FSK modulation (such as in PC modem)
5 - so you can send this modulated signal using simple FM transmitter
6 - now receive the signal by FM receiver (Radio for Example)
7 - demodulate the FSK signal using FSK decoder (available as chip
XR-2211) and then you'll obtain the serial data again .

Click to expand...

Yes, your close to what i want. i actually wish you could help me with the transmitter/receiver circuit (easy designs), and also the interfacing to the Pc. I actually would like to send it through a parallel port as the data would be in that form. But how to go about that is really the problem.


Thanks

001

Hi

You may want to build a 8255 interface card, and use a couple of holtek Encoder/Decoder pairs for the wireless stuff.

Regards

HI,
i can just help u by giving site to get some help from
www.discovercircuits.com/A/alarms.htm