[EE] About key fobs / transmitters / receivers

[enrique]

Hi there Community !

I would very much to read your opinions about current (purchasable) remote control transmitters (key fob like) and receivers.

I am finishing the design of a neighbor’s - community alarm and I need to give each neighbor a key fob which transmits a unique user ID, so I can identify him or her in my system.

As far as I could research, the “only” thing out there are keeloq based systems.

They transmit a 66 bits packet, which includes an encrypted portion (with the actual rolling code, and a copy of the unique ID) and an unencrypted portion including again, the unique ID, button(s) being pressed (up to four channels) and battery low bit.

I am focusing on listening for the unencrypted part, since I can do the users validation / erase, enrolling, etc. on my own system (I just need the unique ID).

Is there any other remote control transmitter / receiver protocol, newer, perhaps, with reasonable price per key fob, that may also transmit a unique ID per unit ? Or this is it ?

Any ideas, comments, or questions are welcome !

Regards,


Enrique

[Van Horn, David]

It's not hard to roll your own protocol.
I would recommend a preamble of some number of 1 and 0 bits, followed by the data you want to send.
Receiving it is a whole lot like decoding conventional barcodes, and is subject to the same sorts of distortions and errors.

RFDuino might be a place to look.
Link has some relatively inexpensive modules.


-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of enrique
Sent: Friday, July 13, 2018 9:26 AM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [EE] About key fobs / transmitters / receivers

Hi there Community !

I would very much to read your opinions about current (purchasable) remote control transmitters (key fob like) and receivers.

I am finishing the design of a neighbor’s - community alarm and I need to give each neighbor a key fob which transmits a unique user ID, so I can identify him or her in my system.

As far as I could research, the “only” thing out there are keeloq based systems.

They transmit a 66 bits packet, which includes an encrypted portion (with the actual rolling code, and a copy of the unique ID) and an unencrypted portion including again, the unique ID, button(s) being pressed (up to four channels) and battery low bit.

I am focusing on listening for the unencrypted part, since I can do the users validation / erase, enrolling, etc. on my own system (I just need the unique ID).

Is there any other remote control transmitter / receiver protocol, newer, perhaps, with reasonable price per key fob, that may also transmit a unique ID per unit ? Or this is it ?

Any ideas, comments, or questions are welcome !

Regards,


Enrique

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist

[Van Horn, David]

You could do worse than emulate UPC with a slightly extended preamble. The encoding of this symbology is pure genius.
http://www.barcodeisland.com/upca.phtml

I've written a decoder for all UPC variants in an AVR2343, which will deal with noise and distortion right up to the theoretical limit.
All the issues of barcodes, including what they call "inkspread" which is "Mark-Space distortion" in RF land, are present and are solved the same way.

I took the tricks I learned in writing that barcode decoder, and wrote new code for the ESI 433 MHz radios:
http://elec-solutions.com/products/input-devices/wireless-radio-controls-rf/rr433.html

The version before me had data errors at ranges as short as two feet.
My version was error free at 1000 feet. Same processor, better code.



-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of Van Horn, David
Sent: Friday, July 13, 2018 9:59 AM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: RE: [EE] About key fobs / transmitters / receivers

It's not hard to roll your own protocol.
I would recommend a preamble of some number of 1 and 0 bits, followed by the data you want to send.
Receiving it is a whole lot like decoding conventional barcodes, and is subject to the same sorts of distortions and errors.

RFDuino might be a place to look.
Link has some relatively inexpensive modules.


-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of enrique
Sent: Friday, July 13, 2018 9:26 AM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [EE] About key fobs / transmitters / receivers

Hi there Community !

I would very much to read your opinions about current (purchasable) remote control transmitters (key fob like) and receivers.

I am finishing the design of a neighbor’s - community alarm and I need to give each neighbor a key fob which transmits a unique user ID, so I can identify him or her in my system.

As far as I could research, the “only” thing out there are keeloq based systems.

They transmit a 66 bits packet, which includes an encrypted portion (with the actual rolling code, and a copy of the unique ID) and an unencrypted portion including again, the unique ID, button(s) being pressed (up to four channels) and battery low bit.

I am focusing on listening for the unencrypted part, since I can do the users validation / erase, enrolling, etc. on my own system (I just need the unique ID).

Is there any other remote control transmitter / receiver protocol, newer, perhaps, with reasonable price per key fob, that may also transmit a unique ID per unit ? Or this is it ?

Any ideas, comments, or questions are welcome !

Regards,


Enrique

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist

--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist