Hi every one,
I have a few questions about the board of this RF remote control.
1. First of all this board uses ev1527 encoder. Although this IC has just 4 pins for buttons, this remote control has 12 buttons. How they have done such thing?
2. The second question is about the usage of these diodes (or maybe zeners). I can not understand why the have used these amount of diodes which is around 20.
3. Can I increase the range of antenna by adding extra antenna (not the TE one the two wires one)? If so, how should I calculate turns and length of them.
4. In 4 channels remote control, when we press a button we send a 24 bit unique data. After 20 bit address we have 4 bit data for buttons. Now imaging one button data is 0010 and another is 0100. Now if I press two buttons which data will be sent. that would be 0110 or other thing?

 

1. First of all this board uses ev1527 encoder. Although this IC has just 4 pins for buttons, this remote control has 12 buttons. How they have done such thing?

4 bits can encode 16 different buttons in one channel or 1 button in each of 4 channels.
I would guess it is using the four bits to represent 16 unique commands in one channel, only 12 of which are used.

The diodes are probably used to set which bits are set for each button. I.e. they encode 12 commands (buttons) into 4 bits.

 

Welcome to AAC.

The datasheet answers your questions 1, 2, and 4.

The 12 buttons are connected through the diode matrix to select 12 of the sixteen possible combinations of 4 bits on the input. This table enumerates the combinations of input and output:

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Generally speaking, it is not legal to modify the antenna on such an unlicensed transmitter. This is true in all countries because the bands they operate in are the subject of international treaty. You are much better off trying to improve the receive antenna which doesn’t have such limitations so long as it is not a transceiver.

The datasheet is attached for convenience.

 

Th

4 bits can encode 16 different buttons in one channel or 1 button in each of 4 channels.
I would guess it is using the four bits to represent 16 unique commands in one channel, only 12 of which are used.

The diodes are probably used to set which bits are set for each button. I.e. they encode 12 commands (buttons) into 4 bits.

Thanks, so we can even use 16 buttons.

 

Tha

Welcome to AAC.

The datasheet answers your questions 1, 2, and 4.

The 12 buttons are connected through the diode matrix to select 12 of the sixteen possible combinations of 4 bits on the input. This table enumerates the combinations of input and output:

View attachment 326920
​

Generally speaking, it is not legal to modify the antenna on such an unlicensed transmitter. This is true in all countries because the bands they operate in are the subject of international treaty. You are much better off trying to improve the receive antenna which doesn’t have such limitations so long as it is not a transceiver.

The datasheet is attached for convenience.

Thanks a lot, so this table answer my 4th question.