Kenwood Stereo Remote Interface

[rjandsam]

Hi, I have a Kenwood double din stereo in my car, I also have a stalk control adaptor that converts the steering wheel buttons from IBUS to a pulse out, this means I can control the Kenwood from the steering wheel no problem. What I now want to do is use a Picaxe to count the pulses from the stalk adaptor going to the Kenwood so that I can control something else.
I have found that the Kenwood is expecting a 9ms pulse followed by a 4.5ms pulse as the lead in then the device data pulses are sent E.g.:


lead in
9ms high
4.5ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
1.0ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
0.5ms high
0.5ms low
1.0ms low

after the device data comes the key data same sort of thing just 9 separate pulses long, the device data is always the same, it’s the key data I need to read and turn into controls.
I don’t know if this is possible with Picaxe as I have never dealt with pulses and counts to this length. I’m really just after some advice from you guys as when I’m stuck you guys always seem to point me in the right direction and I really appreciate it.

Thanks again Rich

 

[westaust55]

Forum member InglewoodPete has done some work successfully to work with the NEC 32 bit codes.
Try a search for the information IWP has previously posted - it may be useful for kenwood systems as well.
(too slow to search from my iPhone hence leaving a search to you)

 

[nick12ab]

IWP's thread or... http://www.picaxeforum.co.uk/showthread.php?18431-Generating-non-Sony-Infra-Red-signals

 

[rjandsam]

Thanks for the replies, it looks like that project is about transmitting the data already collected I need to read the pulses into the Picaxe.
I have found a work around using serin at n4800_8 and it gives me constant unique data for each button so this does not stop me finishing it I am just curious if it can be done the pulse counting way.

Thanks again

 

[inglewoodpete]

...you can lead a horse to water but you can't make it drink...

Have a look at the link for the first thread that nick posted (above). It is definitely written to receive IR signals.

 

[hippy]

Looking at the bit timing it seems it's based upon a 500us bit time ( 2000 baud ) so 2400 baud should be able to read a fair bit of that. At 4800 baud you may be on the edge of missing data but if it works reliably enough then it might be okay.

 

[rjandsam]

Thanks for pointing that out inglewoodpete, i must have selective sight. Thanks nick12ab for posting a link to the relevant thread.
Hi hippy, just tested with 2400 baud and it is unique for each button press so must be grabbing most of the data as you suspected.

please forgive my poor reading skills for missing the link earlier I suppose I just glanced and saw a single link, let that be a reminder to me to always read an entire post not just what I picture.

Thanks all.
Rich