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General Category => Your projects => Topic started by: LoneWolf on December 05, 2013, 00:42:36 AM

Title: [HELP] Air Conditioner remote checksum
Post by: LoneWolf on December 05, 2013, 00:42:36 AM
Hi, I am trying to make a programable remote for my Air Conditioner I have managed to figure all the info I need about the protocol except how the checksum at the end is calculated.

An article that helped me a lot was this one: http://www.pcbheaven.com/userpages/Reverse_Engineering_Fidji_Air_Condition_IR_Protocol/index.php?topic=worklog&p=1

I have uploaded a file with my data and some analysis I already did.
https://www.dropbox.com/s/mjgvmhnr1otxin2/data.xlsx

There seems to be some sort of pattern in there but I haven't been able to figure it out yet.
Anyone willing to help me please?
Title: Re: [HELP] Air Conditioner remote checksum
Post by: kam on December 05, 2013, 11:37:01 AM
hello lonewolf.
Indeed there seems to be some sort of a pattern. But i need more data to help.
First of all, i need all data in binary form before your analysis. And what is the "checksum" and "sum" fields?
Most important: I need to know all bits for each command.
Title: Re: [HELP] Air Conditioner remote checksum
Post by: LoneWolf on December 05, 2013, 16:48:47 PM
Unless I made a mistake, there should be 2 sheets in that XLSX file, the sheet called data has the binary form.

I should have provided more information, the commands have 17 bytes each, each column in the data sheet is a byte, (excel eats the first bytes if they are zero) checksum is the last byte and the one that I believe to be the checksum.

Here is another file: https://www.dropbox.com/s/4eytexnsst1d0jg/codes.log the one that has the collection of data I used to find what bits control what.

If you need any more information just ask :)
Title: Re: [HELP] Air Conditioner remote checksum
Post by: kam on December 07, 2013, 01:08:25 AM
I tested several ways, cant find a solution. Are you sure about the 7th byte? I mean, it makes no sense. It should be something like 1,2,3,4, etc.... Or another row...
Title: Re: [HELP] Air Conditioner remote checksum
Post by: LoneWolf on December 09, 2013, 21:39:20 PM
If you mean the temperature one, seems to be calculated like this (temperature-4)*2 and them the bit order is reversed, seems to make sense to me.

Here follow my notes about the bits

1-5 CONSTANT
00000010 00000000 00101000 00000001 11000010


6 FAN+MODE
4Bits
0100 AUT
0101 MIN
0110 MAX
0111 MED
4Bits
0000 AUTO
0001 DEHU
0010 HEAT
0011 COLD

7 Temperature  (TEMP-4)*2 AND REVERSE ORDER

8-13 Related to timer, can be constant like this
00000010 11000100 00000000 00010110 00000000 00000000

14 FLAP 4bits+4bits
0000 ALL
1000 AUTO
0100 1
1100 2
0010 3
1010 4
0110 5
1110 6

4bits
normally 0000
0100 when setting timer


15-16 Constant
00000000 00000000

17 CHECKSUM

Sorry for not posting this before, the other posts were done with limited time.
Title: Re: [HELP] Air Conditioner remote checksum
Post by: kam on December 22, 2013, 08:52:01 AM
Any news from the front? I haven't managed to find enough time to work on this thing :/