Author Topic: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial  (Read 22049 times)

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Offline open loop

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #25 on: August 16, 2013, 04:30:43 am »
Excellent video and came at the pefect time.

I was messing about with an IR based project where I wanted to time 100 IR beam breaks. The LEDs arrived in the post but not the photo transistor. So I thought, "I know... I tore down an old sky HD box a while ago for the HDD I'll use that IR receiver". Worked out the connections but it didn't work with anything except the stero remote checked the LED with my phone camera and it worked!

What was happening? - now I know my LED did not generate the required 38kHz carrier! .... As David says "I hope your project doesn't work"!. I have noticed that newer phone cameras now have an IR filter so you can't see the IR LEDs working anymore.




 

Offline Legit-Design

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #26 on: August 16, 2013, 04:56:27 am »
I have noticed that newer phone cameras now have an IR filter so you can't see the IR LEDs working anymore.
This smells like bullshit.
All digital cameras still have IR cut filter, it just doesn't block IR remote signals too well. I find it more plausible that your project isn't sending IR signals, than they have included ir cut filters that completely cut all IR, even remote signals. What phone are you using?
 

Offline open loop

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #27 on: August 16, 2013, 07:32:45 am »
I do agree with you that digital cameras have an IR and that the average remote would be seen due to it not blocking these particularly well.

I often used my iPhone 3GS to test remotes to see if the problem was with the remote or the appliance. When our cable box played up I tried this trick on my wife's iPhone 4S and my iPad 3 and I could not see the tell tale flashing you normally see so there must be something going on with the newer cameras, why I am not sure...

The reason my project did not work was because I was trying to use a constantly lit IR LED with a IR receiver not a photo transistor. Which Dave's video explained perfectly.



 

Offline Legit-Design

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #28 on: August 16, 2013, 07:42:35 am »
I do agree with you that digital cameras have an IR and that the average remote would be seen due to it not blocking these particularly well.

I often used my iPhone 3GS to test remotes to see if the problem was with the remote or the appliance. When our cable box played up I tried this trick on my wife's iPhone 4S and my iPad 3 and I could not see the tell tale flashing you normally see so there must be something going on with the newer cameras, why I am not sure...

The reason my project did not work was because I was trying to use a constantly lit IR LED with a IR receiver not a photo transistor. Which Dave's video explained perfectly.

http://www.instructables.com/id/See-Infrared-LED-Light-with-an-iPhone-4/?ALLSTEPS
Use the front facepalm camera on your iDevices. I understand you like to use the simple iDevices, but occasionally you have to press a button.  :-/O
 

Offline HeyTom

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #29 on: August 17, 2013, 12:03:44 am »
Hardware PWM would be better.

For hardware PWM, I have a Pic PWM Calculator you might find handy at http://micro.alleypress.org/  It also works in a browser on a smart phone.

It let's you find stuff like
  • min/max frequencies
  • periods and "On Times"
  • how many bits of resolution
  • number of steps


I'm open to any feedback to make it better
-Tom
 

GalvanicResonse

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #30 on: August 18, 2013, 12:15:19 pm »
Re: IR receiver and phototransistor examination of carrier and stripped carrier :
"Traps For Young Players" file.

Hi - I am new to the blog and forum.
The video was very informative. I don't have the fancy pants equipment but I wanted to view the output of some of the remotes around the house on an analog scope. I scrounged up a photo tranny and an IR receiver from the junk box. This note is just to add to the "TFYP" file on this aspect of the subject.

There are two things that I bumped into while trying this out.

1) IR receivers - I was unaware of what these things do, so the video encouraged me to try one out. The trap here is that the pin-outs are not uniform across manufacturers. I had a few that had been removed from consumer gear but they have no part number to look up. My solution was to remove another one that was still in place on some junk board, but paying attention to the circuit traces as to which ones are the likely suspects ( example, an electro cap across two pins was good evidence that I had Vcc and ground). So my advice to a beginner on this is to pay attention when you remove it and store it away with a bit of documentation.

2) Detecting the carrier. My first circuit for this was a simple grounded emitter ( Vcc - 2k2 - photo-t collector , photo-t emitter grounded). This detected IR from a remote but I didn't see a carrier. I then tried 4 other remotes - same results. The output looked about the same as that from the IR recevier. I thought that I was unlucky and none of my remotes used modulation. But unlucky 5 times ?? I cranked up the volts/div on the scope and could see tiny sawtooth waves on the low going parts of the signal. I started to wonder if the lone photo-t was not fast enough to follow 38 khz. I googled 'phototransistor circuits' and got a few hits that were real app notes. When I built the circuit in the Sharp app note ( figure 11a ) the response was fast enough that I could see ( and measure the period of ) the  carrier (36 k in 5 out of 5) .   That made for a fun evening. Thanks. 

If the URLs don't work, google
 
'Photodiode/Phototransistor Application Circuit' for the Sharp app note and
'application note an-3005 design fundamentals' for the Fairchild one

Fairchild app note

http://www.fairchildsemi.com/an/AN/AN-3005.pdf?

Sharp app note ( this had the solution that I needed )

http://physlab.lums.edu.pk/images/1/10/Photodiode_circuit.pdf

GR
 

Offline westfw

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #31 on: August 18, 2013, 05:45:51 pm »
Quote
it's not (yet) 100% clear to me how much the user is allowed to mess outside of the official sandbox.
It *is* a microcontroller with no "protection."  "Arduino" is little more than an IDE, some initialization code, and some libraries.  Anything is "allowed"; you can reinitialize all the peripherals, ignore the libraries, and write code in assembler if you want.  (of course, once you start re-programming the peripherals, all bets are off WRT the official libraries continuing to work...)
 

Offline mrwildbob

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #32 on: June 29, 2015, 07:37:42 am »
Hello Everyone,  I'm slowly getting back into programming after watching Dave/EEVblog over the years.  Very inspiring.  I need a little help.  I would like to use this code for a different project but with out the 38KHz carrier frequency.  I've tried editing the code to work with my application but can not seem to get the desired results.  Can someone help me with this?  I just need to send out a 550 byte code out pin 2.  thanks
-boB
 

Offline ftonello

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Re: EEVblog #506 - IR Remote Control Arduino Protocol Tutorial
« Reply #33 on: February 29, 2016, 07:05:55 am »
Doing some tests here....Now i understand what Dave said about capturing these waveforms in a 2.5K oscilloscope (a TBS 1072B-EDU).
Do the job,but with small resollution and losing some carrier freq.





Any ideas to improve the signal capturing?

Capturing the data from a Samsung DVD remote controler, with a ZILOG Crimzon  ZLR2802GR54WL controller on board.





Att
« Last Edit: February 29, 2016, 07:07:32 am by ftonello »
Hi from Brazil!!!
 


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