Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

Why does the "generated" signal fail to work?

 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Accessories
View previous topic :: View next topic  
Author Message
Rhye



Joined: 23 Feb 2018
Posts: 1



PostLink    Posted: Mon Feb 26, 2018 7:25 am    Post subject: Why does the "generated" signal fail to work? Reply with quote


        Register to remove this ad. It's free!
I am trying to replicate the remote control for my Sony home theater system. I started with anaylzing the demodulated signal of power on button using a TSOP1738 IR demodulator(http://www.kynix.com/Detail/840529/TSOP1738.html). It looks like this:



You can see the signal (along with the decoded command). Next I replicated the signal using the Arduino (and as per SIRC protocol, chose 1/4 duty @ 38Khz). Below is the signal of a complete one to show the code sent and a zoomed one to show the 38Khz 25% duty burst within the signal.





Now to drive an IR LED using this signal, I fed this into a 2N2222 NPN BJT transistor's base with its collector connected to +5V and base to IR LED -> Series Resistance -> GND. And to test the signal I fed this "generated" signal through the TSOP1738 again and probed the output.



The signal I get looks like an IR signal except for the 1's (when TSOP1738 goes LOW) instead of being LOW for a duration, as in the first image. I see a lot of toggling going on:



The "generated" signal, of course, does not work. Any idea what's going in here ?
Back to top
barclay66



Joined: 27 Jun 2011
Posts: 1241
Location: Germany

TV/Projector: Marquee 9500 Ultra


PostLink    Posted: Mon Feb 26, 2018 10:28 am    Post subject: Reply with quote

Hi,

The series resistor to the tranistor's base should be much lower, between 1K to 4.7K. Otherwise, the transistor isn't switched off reliably when the arduino's output goes low...

Check this out: http://forum.arduino.cc/index.php?topic=147852.0

Regards,
barclay66
Back to top
View user's photo album (25 photos)
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Accessories All times are GMT
Page 1 of 1
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum