Cytron Technical Forum

hello,

May i know how many input can install for pic16f876A? as i knew, it is 5 channel...
This is because that i'm going to do a WIRELESS SMOKE DETECTOR.
An instance, i want install 3 sensors(transmitter) in 3 room respectively.
But i want it sent a signal to a room(security room)/receiver, the receiver will show in LCD while sensor detect and shows which room are detected smoke in the SAME LCD also~

please do not hesitate to comment or answer it. ASAP. THANKS ALL!!!
IF U DON'T UNDERSTAND MY BROKEN ENGLISH, PLEASE LOOK AT MY ATTACHMENT(PICTURE), TQ!

What is the output of the wireless receiver when smoke is detected? If it is a logic level H or L, you may connect them to 3 of the Port C pins say RC0-RC2 configured as digital. The LCD display can be connected to Port B (7 pins used). That will leave 5 pins on port C & 6 on port A for your buttons and LED.

Allen

The output of the wireless receiver should be:-
1) LCD,"will showing which detector sense smoke"
2) BUZZER, AND
3) incoming call/CELLPHONE(PIC16f84a).
''When get a signal from receiver circuit, cellphone will automatically call to the person who set in phone system(contact)''.

But back to the topic,
1)how is the connection for 3 smoke detector to PIC? still need 3 transmitter and receiver? or just direct install smoke detector?
2)how is the connection for LCD (is applying another PIC circuit or direct connect to PIC16F876A?)?

THANK YOU~

If you look at the wireless smoke detector sold by cytron..

http://www.cytron.com.my/viewProduct.ph ... ke%20Alarm

It came with a 315MHz RF Transmitter and uses 9V battery. The problem is you have to ID the Tx to see which room the alarm was from. To do that, you need to add an encoder on the RF Tx module and a decoder on the RF Rx Module. The encoder/decoder can be PT2262 and PT2272. Google on these 2 chips to see how to use them. So you need 3 RF Rx with PT2272 so each will receive alarm from each detector.

But if you are good in programming and knows exactly how the decoder works, one RF receiver would be enough. Once an alarm is received from 1 of 3 rooms, the signal is decoded by PIC software to identify the ID of the Tx and you'll know the signal is from which room.

Buzzer is easy. Just drive it with one of the port pin through a transistor or MOSFET. The LCD can be connected directly to the 876A. As for the H/P interface, it looks like you already know how to do it through another 16F84A PIC.

You may download the PR13 documents to see how cytron do the project.
Allen

But refer back to cytron circuit PR13,
- port B(RB0,1,2) = 3 switch's(PB)
- port C(RC1,2,3) = 3 LED's,(RC0=BUZZER)
- RA0 connect to one PT2272 decoder~
Or it doesn't matter that what pin figure(port a/b/c) between these connection?

Can i install 3 decoder & 3 encoder(with 3 smoke detectors respectively) to 876A? but is it using the same frequency(315MHz) between these 3 encoder & decoder?
And where i can connect the other 2 decoders to 876A? is it Port A (RA0,1,2)?

Let's say that LCD is direct connect to 876A;
- which terminal i should connect with LCD between 876A(both terminal connection)?
- did the LCD sell in cytron?
- did i need to add the program on 876A if LCD installed(show the room no. if sensor detected)?

Thanks a lot~~

In addition, can i ask that how to get the circuit diagram/connection(schematics) for encoder(pt2262 only) in we suggestion?
this is because that i am going to draw & produce the circuit ourself~

thank you guys~~~

sse WROTE:In addition, can i ask that how to get the circuit diagram/connection(schematics) for encoder(pt2262 only) in we suggestion?
this is because that i am going to draw & produce the circuit ourself~

thank you guys~~~

The example circuit is here:

http://www.escol.com.my/Datasheets_specs/RF%20Modules%20AppNote.pdf

http://postimage.org/image/jvdbztai5/full/

Allen

sse WROTE:Or it doesn't matter that what pin figure(port a/b/c) between these connection?

No it doesnt matter.

sse WROTE:Can i install 3 decoder & 3 encoder(with 3 smoke detectors respectively) to 876A? but is it using the same frequency(315MHz) between these 3 encoder & decoder?
And where i can connect the other 2 decoders to 876A? is it Port A (RA0,1,2)?

Yes you can. Even though the freq is the same, how you set the addresses would make the difference. Room 1 = 00001010, Room 2 = 00000101, Room 3 may be 10100000 etc.

sse WROTE:Let's say that LCD is direct connect to 876A;
- which terminal i should connect with LCD between 876A(both terminal connection)?
- did the LCD sell in cytron?
- did i need to add the program on 876A if LCD installed(show the room no. if sensor detected)?

I would use Port B for LCD. Refer to PR3.
Yes, they did and they still do.
Of course, the PIC is very dumb without a program.

Allen

hello,

As ur comment;

I followed these pin connection from circuit PR13, where =(PIN 1,8,9,10,19.20,24,27 & 28).

1)how many terminal of LCD I should connect to 876A?
2)actually, did i need to buy circuit PR3 to connect with 876A?
3)If i want add the incoming circuit(h/p interface), where i can connect the 84A(is it using 2 connection from 84A) to 876A?
Im totally confusing with the circuit~
Thanks for reply~

sse WROTE:1)how many terminal of LCD I should connect to 876A?
2)actually, did i need to buy circuit PR3 to connect with 876A?
3)If i want add the incoming circuit(h/p interface), where i can connect the 84A(is it using 2 connection from 84A) to 876A?
Im totally confusing with the circuit~

1. That depends. You can have RS, Enable, R/W + 8 data bits OR RS, Enable, R/W + 4 data bits.
[edit] If you use SK40C the LCD interface is using RB4 & RB5 plus RD0-RD7 in 8 bit mode.

I'd suggest to use 16F877a or 16F887 to replace the '876A. The price is not much different but they are 40 pin PDIP and have more ports to manipulate if you're getting short of them.

2. Buying PR3 is a good idea. It comes with SK40C and the LCD and the PIC as well. Then you can start your project with a breadboard next to the SK40C to connect your PT2272. Dont forget to get the UIC00B programmer too. You'll need it to program the PIC.

3. How to interface to the HP have been replied on another of your post....

Allen