Req. PT2264 based RF 12 Button Transmitter Schematic

[localcrack]

Is anybody has PT2264 RF encoder chip based 12 button remote transmitter schematic ?
Please share

[Parmin]

I believe it is a simple matter of doing a binary coding for the transmitter.
You have 1 nibble of data to work with and thus can use it to go 16 channel, theoretically.

[localcrack]

Yes Parmin it's 4 Bit data only but I am confused how to wire it with push button to generate 2^4 (16) code
If you have any idea please share

[titi]

Hi localcrak,

This is how to generate a four binary code with diodes matrix, this example is for 8 keys, but once you understand for 8 keys, it is not complex to add the last four keys.
Sorry for the poor quality of the drawing...


The top diodes (vd14 to vd17) is a trick to power the IC when you push a key.

Some complements at this address : http://www.seekic.com/circuit_diagram/Remote_Control_Circuit/The_8_line_remote_control_emitterCS901_circuit.html

Best regards.

[pickit2]

I see you still don't read data sheets.
you still working on your fan?

[localcrack]

Hello Pickit2 I have read complete datasheet and I find same circuit that you have posted that I don't require.
Kindly suggest me how do I implement 12 button according to datasheet

[pickit2]

so you don't require the data sheet? how are you going to learn?
so make it easy, on yourself, and split it down a bit.

Ask do you rarely need the full 16 bit address and the 4 bit data?
it would be easy to use A0-A7 as address and (A8-A11 - also used as D3-D0)

[LabVIEWguru]

Localcrack:
The point of my friends here is they want you to make the attempt - try to understand. There are many things that I do not understand, but that is when you get the documentation and try to learn. After you make the genuine attempt to figure it out for yourself then it is okay to ask for help. They are not being difficult, they are trying to equip you with tools.

From Pickit2 data sheet:
A0 ~ A7 I
Code Address Pin No.0 ~ 7
These ten tri-state pins are detected by PT2264 to determine the encoded waveform bit 0 ~ bit 9. Each pin can be set to “0”, “1” or “f”

A8/D3 ~ A11/D0 I
Code Address Pin Nos.8 ~ 11/Data Pin No.0 ~ 3.
These four tri-state pins are detected by PT2264 to determine the encoded waveform bit 10, bit 11. When these pins are used as address pins, they can be set to “0”, “1”, or “f” (floating). When these pins are used as data pins, they can be set only to “0” or “1”.


Now, from page 6 of the data sheet:

PT2264/PT2294 have a maximum of twelve (12) Address Bits, four (4) Address/Data bits. The following diagram shows the code bits with their corresponding pins.

First bit transmitted
↓
A0 A1 A2 A3 A4 A5 A6 A7 A8/D3 A9/D2 A10/D1 A11/D0 SYNC BIT

Now, if you look at the chart on page 6 you see that:

The Code Bits A0 ~ A7 and A8/D3 ~ A11/D0 are determined by the states of A0 ~ A7 and A8/D3 ~ A11/D0 pins. For example, when the A0 (Pin No. 1) is set to “1” (VCC), the Code Bit A0 is synthesized as “1” bit. In the same manner, when it (A0 Pin) is set to “0” (VSS) or left floating, the Code Bit A0 is
synthesized as a “0” or “f” bit respectively

What it is telling you is every message contains 8 address bits and four data bits. So, if you always leave the 8 address bits in some floating state you will only have 4 distinct messages. But, if you change the state of A0 (hint - see if the address bits are pulled up or down internally) + the 4 data bits, you will have 4 new messages! return A0 to the original state and change A1 + the 4 data bits, you will have 4 new messages.

Look at the circuit titi kindly provided - VD1 - VD13   Why are those diodes in the circuit? What happens if you reverse a diode?

Now, you get to do something else all engineers love to do, build it and experiment changing the address bits of the device, use pushbuttons on d0-d3 and see how the message changes.


I am not being insulting, you need to have data sheets for all these parts before you start building. The PT2264 has pin 1 marked. Diodes have a polarity. LEDs and Zener diodes have a polarity. All electronics have Magic Smoke in them that makes the device work. If you do something wrong the Magic Smoke comes out and the device doesn't work any more. Everyone has done this, too. (well, maybe not titi and Parmin - I think they are too smart to do such things)

[localcrack]

Sorry to all hero member, senior member & moderator as they feeling badly due to my this post.

I already built a 4 button remote by reading datasheet, as schematic already given in datasheet for 4 button remote. Now my thing is only that how to extend 4 button remote to 12 button remote so I try to search in datasheet and also googling but can't find proper information so I posted my question in this forum.

Not every people is genius. If so no one needs engineers.

Titi has forwarded perfect things how to generate binary code using diode matrix. I am planning to implement this thing and make 12 button remote.

[LabVIEWguru]

No one is feeling bad. You do not need to be a genius. I do not think you will find many people here that claim to be a genius.

We are attempting to "Open the Door" for people. I am sorry, I have failed miserably to do this for you.

[cadence]

Hi localcrack

It seems there comes a time in everyone's electronics journey that we need to encode keypads to binary.
My first time I approached it with diodes too, as per titi's proposed circuit.  It's a good way to do it and it works, but wiring the 22+4=26 diodes it requires for 12 buttons may prove to be a bit frustrating.

There are other solutions - one is a dedicated IC: the MM74C922 for example.  It's far easier to wire and it will operate up to +15V which will suit the 12V PT2264 voltage operating requirement but it's more expensive than 26 diodes.  There's an example of its use in the project 'Access-Control System' page 42 of Electronic Projects issue 22: http://www.sonsivri.to/forum/index.php?topic=53849.msg155032#msg155032

If you wanted to take it one step further you could implement the same functionality in a PIC micro (or other embedded chip).  It's fairly simple to do and quite satisfying.  Check out a related article: Google "Alternative of 74C922 16 Key encoder IC - embedded systems".  You'd need to select a PIC that would be happy operating at 12V though.

Also if you wanted to read up on some more obscure key-encoding techniques check out the microchip Compiled Tips & Tricks Guide.  It's free online as a pdf.

...every message contains 8 address bits and four data bits. So, if you always leave the 8 address bits in some floating state you will only have 4 distinct messages. But, if you change the state of A0 (hint - see if the address bits are pulled up or down internally) + the 4 data bits, you will have 4 new messages! return A0 to the original state and change A1 + the 4 data bits, you will have 4 new messages.

You could experiment with this but as the 8 address pins in a matching PT2294 receiver would be set to fixed, predetermined levels ( matching the 8 address pins in its partner PT2264 transmitter) changing the A0 or A1 address pins in the transmitter would indeed generate 8 new messages but those new messages would be ignored by the receiver because the transmitter and receiver addresses would no longer be matching.  However if you're not using a matching receiver chip then it would work.

If your requirement is for a one-off build then perhaps wiring 26 diodes is the best way to go, as per titi's encoder suggestion.

Best of luck!

[Parmin]

Localcrack

Forget about diode matrix.
Just pop in a binary to BCD, surely a microprocessor such as PIC16F876 is cheaper and MUCH NEATER than a bunch of diodes.

[pickit2]

Last topic went to 30 posts and this just smacks of a repeat, both topics should have been solved by reading a data sheet.

http://www.sonsivri.to/forum/index.php?topic=57649.msg165642#msg165642

[Parmin]

So here is an answer to localcrack

Ok I can help with your request,
provided that a (respectable amount of) payment is made to Sonsivri's fund.
For that I will draw full circuit diagram, complete with PCB board diagram if required.
Or if you require for me to design and program the solution with microprocessor this can also be achieved..