USB-UIRT Codes for Canon EOS 350D

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USB-UIRT Codes for Canon EOS 350D

Postby Tal Aloni » Sun Jul 10, 2016 7:41 pm

After a few hours of research, I was able to remotely control a Canon EOS 350D (Digital Rebel XT) using USB-UIRT.
The Canon RC-1 has been reverse engineered, and the protocol is detailed in this very helpful post.
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Parameter                     Original RC-1      Tolerance
Num. of pulses                16                 9 - 22
Burst frequency               32700 Hz           29800 - 35500 Hz
Delay for immediate trigger   7.33 ms            7.0 - 7.7 ms
Delay for 2 s delayed trigger 5.36 ms            5.1 - 5.7 ms


Based on this protocol, I was able to manually craft RAW UIRT codes that worked :)

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Immediate      (@35KHz): R4E2010810110
2 Sec. Delayed (@35KHz): R4E201080BC10


Notes:
- When the IR emitter is said to be "on" it is actually turning itself on and off at the carrier frequency.
- At 35000Hz each cycle is ~28.57 uS, so 7.33 ms are 257 cycles (0x101).
- At 35000Hz each cycle is ~28.57 uS, so 5.36 ms are 188 cycles (0xBC).
- An inter-code delay of 1.024 seconds (20000 x 51.2uS ) was chosen arbitrarily.

References:
UIRT RAW format: http://www.usbuirt.com/phpBB3/viewtopic.php?f=4&t=76
Tal Aloni
 
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Joined: Tue Jul 05, 2016 10:12 am

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