Comments on: chronos.chschmid.com

By: CSK

CSK — Fri, 13 Apr 2012 05:52:21 +0000

hello again… okay i think i am too close to what i want just that… i am missing just one key… i just wanted to know how you arrived[calculated] the Data Rate 1.599312 kBaud and what was the Resistor (Rosc) used in the HT12E / Decoder.

By: CSK

CSK — Thu, 12 Apr 2012 02:46:04 +0000

firstly sorry to flood your blog with my comments ur the only person who can save me
hey based on the graph in datasheet of the decoder HT648L i figured out Fosc == 200kHz for resistor i had used earlier 150kOhm, also there is a frequency division happening internally Fosc / 33 and 1 address/data bit uses 3 cycles of Fosc / 33
now i have data but i really donot know how to proceed further… as it looks quite different from HT12E.. so i think now i have to determine how can i replicate the modulation frequency using acuurate number of bits /cycles to represent data

By: CSK

CSK — Thu, 12 Apr 2012 00:56:10 +0000

Thank you for replying.. after researching on various datasheets / RF studio realized that really what you have provided should actually suffice all the needs.

btw there is another discovery i have made to add more trouble to my chronos research life.. i had actually replaced all HT12E encoders i used few years ago for “complete home automation project via bluetooth / sms” with HT640 as it has 8 bit data unlike ht12e which has only 4 bit data.

so it all starts again… wish i had an oscilloscope.. by looking at the ht12E and ht640 datasheets i have figured out what data i should send, but modulation frequency is the tricky part, as there is no formula provided for “fosc” based on resistor used and i dont have an oscilloscope

so either i ll have to replicate standard values of resistor / VDD as mentioned in HT640 datasheet or i need to switch back to low data bits HT12E currently sticking on to HT640 lets see..

just in case if u manage to have a look at HT640 datasheet and have spare time to discuss please drop a mail

btw based on ht12E datasheet findings:
i think the pcb soldered values you provided are inverted or am i missing something here..

SYN == first bit always 1 for sync purpose
ADD == Adddress bits 12 for HT12E
DAT == Data bits 4 for HT12E
001 001 011 011 001 001 011 011 001 001 001 001 001 (from oscilloscope data)
SYN ADD ADD ADD ADD ADD ADD ADD ADD DAT DAT DAT DAT (HT12E datasheet)
1 1 0 0 1 1 0 0 1 1 1 1 1 actual values (HT12E datasheet)
0 0 1 1 0 0 1 1 0 0 0 0 0 Christian

By: Christian M. Schmid

Christian M. Schmid — Wed, 11 Apr 2012 13:39:55 +0000

Enlarge the TI SmartRF Studio screen shot above, make sure all settings in the “RF parameter” area are the same as in the screen shot (apart from the base frequency, which is somewhere around 433 MHz for you, depending on the RF module)

That should give you the correct seetings for the emulating an HT12E encoder with a 433 MHz ASK/OOK RF module.

By: Christian M. Schmid

Christian M. Schmid — Wed, 11 Apr 2012 13:35:25 +0000

Thanks for your comment.
I think that “writing some library for easy RF” is neither a good idea nor necessary. To be frank, with the integrated MSP430 + transceiver + the TI’s RF studio + the source code it is as easy as it gets

The thing is the transceiver is so highly configurable that you can do almost everything that is using 868 or 433 MHz in your case. Because of the many parameters that you can choose the library approach, you would need a really really large library to cover all possible cases of use (ASK, PSK, packet mode, zigbee, …)

Using TI’s SmartRF Studio for testing and for generating the register settings + using the C libraries that come with the watch works fine.

By: CSK

CSK — Tue, 10 Apr 2012 15:23:49 +0000

Also can you please suggest what changes should i make in RF parameters for my watch 433 Mhz
{to replicate a 433MHz RF transmitter with HT12E encoder}

By: CSK

CSK — Tue, 10 Apr 2012 02:07:09 +0000

Hey Awesome work!!
so far the best chronos reverse engineering stuff.

i really dont like the idea of having an intermediate “PC” in projects, ur idea of watch talking to devices directly is what i was looking for. infact before buying the watch i assumed this could be done very easily.

i bought a 433 MHz as in India i get a lot of RF transmitters and recievers using that RF range. but i am lost as its not so easy for me to understand the Rf communication ez430 is using, just wish if experts like you can write some library for easily sending RF commands using ez430 {prefrebly 433Mhz}

btw thanks again cool idea

By: Fischbeck

Fischbeck — Sat, 07 Jan 2012 17:45:11 +0000

Thank you very much If I had read the documentation for the HT12E better, than I had seen this info earlier

greetings Fischbeck

By: Christian M. Schmid

Christian M. Schmid — Sat, 07 Jan 2012 10:58:56 +0000

I have added additional information on how to extract the code from the remote PCB soldering. Hope you enjoy playing around with your chronos!

Greetings Christian

By: Fischbeck

Fischbeck — Fri, 30 Dec 2011 06:04:14 +0000

Good morning
Dear Mr. Schmid,
in Part 2 you wrote: …I now even have two dimmers in my apartment, no measurements were required for the second dimmer, as the code can be read from the soldering.

Now my question:
Is it a hex-value, a bit-value or a decimal value which is on the soldering?

for example your bitcode in sample 1. Is there a decimal Code like 80953053769 on the soldering-board or a hex Code like 12D92D9249 ?

Greetings Mr. Fischbeck