IR TV Remote Jammer

S

SampleBandit

Guest
Howdy all,

I am building a simple tv remote jammer using the simple 555 timer
chip. I don't want to get as extreme as a microcontroller. I have done
various testing with duty cycles and frequencies. I can easily make it
tunable within the 36-40khz range. The particular tv target I am after
is a magnavox using RC5 at 36khz. I went to RadioShaft and got 2 of
the following IR Led: Specifications for the 276-143C are as follows:

• Radiant Intensity (mw) 7.368
• Peak Wavelength (nm) 940
• Forward Voltage (V) 1.28
• Half View Angle (Degrees) 36.36

I have sucessfully jammed the tv as long as my circuit is 6 foot away
from the tv. My present circuit setup uses 2 individual 2n2222a NPNs
each driving 1 IR Led on the collector side. I have experimented with
current limit resistor down to 47 ohms and the IR Leds were just
slighly warm. I am sure that this is not necessary and there is a more
effieicnt way.

Now, the age old problem. How to make the range as efficient as the tv
remote itself. I find it hard to believe that my circuit powered by a
9 volt battery cannot overcome the signal from the 3 volt powered tv
remote. I have experimented with shorter pulse duty cycle as well as
50% (or as close as the 555 can do), PNP vs. NPN transistors, IR Leds
in series on 1 transistor, collecor and emmiter led connections.
So what can one do to increase jamming range? I have read that making
the duty cycle of the pulse shorter makes the IR led transmit further.
I didnt have any luck. lso this make me wonder how the receiver calcs
the frequency. From rising edge trising edge? The newer tv remote
circuits may be much better at rejecting noise but if I have been
successful at 6 feet then I should be at a longer range.
I have thought of the issue of IR Led transmission scope. The ones I
bought from RadioShaft are 36 degrees. I am using 2 of them and should
be able to cover some ground without a focusing lens. My tv remote has
2 and no focus lens. How do they do it? :) Is a 50% duty cycle
necessary? Do I need to be more precise then a 555 timer? I have been
to many web sites and read many newgroup postings but this
issue seems to be the search for the IR Holy Grail! I would like to
keep it simple.

I now call upon you IR wizards for help :)
Thanks,
Bob
 
An improvement would be to on-off modulate your carrier at something like 1KHz. This will corrupt
the signal much better - with an unmodulated carrier, much of your signal will be filtered out due
to the receiver's AGC.



On 20 May 2004 05:37:18 -0700, bschumann@thompsonpump.com (SampleBandit) wrote:

Howdy all,

I am building a simple tv remote jammer using the simple 555 timer
chip. I don't want to get as extreme as a microcontroller. I have done
various testing with duty cycles and frequencies. I can easily make it
tunable within the 36-40khz range. The particular tv target I am after
is a magnavox using RC5 at 36khz. I went to RadioShaft and got 2 of
the following IR Led: Specifications for the 276-143C are as follows:

• Radiant Intensity (mw) 7.368
• Peak Wavelength (nm) 940
• Forward Voltage (V) 1.28
• Half View Angle (Degrees) 36.36

I have sucessfully jammed the tv as long as my circuit is 6 foot away
from the tv. My present circuit setup uses 2 individual 2n2222a NPNs
each driving 1 IR Led on the collector side. I have experimented with
current limit resistor down to 47 ohms and the IR Leds were just
slighly warm. I am sure that this is not necessary and there is a more
effieicnt way.

Now, the age old problem. How to make the range as efficient as the tv
remote itself. I find it hard to believe that my circuit powered by a
9 volt battery cannot overcome the signal from the 3 volt powered tv
remote. I have experimented with shorter pulse duty cycle as well as
50% (or as close as the 555 can do), PNP vs. NPN transistors, IR Leds
in series on 1 transistor, collecor and emmiter led connections.
So what can one do to increase jamming range? I have read that making
the duty cycle of the pulse shorter makes the IR led transmit further.
I didnt have any luck. lso this make me wonder how the receiver calcs
the frequency. From rising edge trising edge? The newer tv remote
circuits may be much better at rejecting noise but if I have been
successful at 6 feet then I should be at a longer range.
I have thought of the issue of IR Led transmission scope. The ones I
bought from RadioShaft are 36 degrees. I am using 2 of them and should
be able to cover some ground without a focusing lens. My tv remote has
2 and no focus lens. How do they do it? :) Is a 50% duty cycle
necessary? Do I need to be more precise then a 555 timer? I have been
to many web sites and read many newgroup postings but this
issue seems to be the search for the IR Holy Grail! I would like to
keep it simple.

I now call upon you IR wizards for help :)
Thanks,
Bob
Click to expand...
 
SampleBandit wrote:

Howdy all,

I am building a simple tv remote jammer
Click to expand...
You nasty mean little punk. Don't you have anything better to do ;)

using the simple 555 timer
chip. I don't want to get as extreme as a microcontroller.
Click to expand...
Lazy-ass. Learn how to program PIC's. They are delicious and nutritious.

• Radiant Intensity (mw) 7.368
• Peak Wavelength (nm) 940
• Forward Voltage (V) 1.28
• Half View Angle (Degrees) 36.36
Click to expand...
You may want to try an 880nm IR LED. You can probably find a better IR
LED in the Digikey catalog.

I find it hard to believe that my circuit powered by a
9 volt battery cannot overcome the signal from the 3 volt powered tv
remote.
Click to expand...
It could be that your not using a really annoying modulation signal. Try
modulating the 36 KHz carrier with a signal that jams the bit-rate of
the remote, something like 100 Hz. Use a variable resistor to control a
10Hz - 1000Hz square wave osc, and feed it and the 36 KHz carrier into a
NAND gate.

Better yet, rip-off somebodys code for a PIC. Program the PIC to be
REALLY mean and obnoxious, making the TV randomly change channels and
turn on and off every three or four minutes. Better yet, make the
channel-change interval random too.

I hear you can jam human brain waves by transmitting 50uS bursts of
pulsed microwaves at the 10 Hz alpha freq.

--
Scott

**********************************

DIY Piezo-Gyro, PCB Drill Bot & More Soon!

http://home.comcast.net/~scottxs/

**********************************
 
Ian Stirling wrote:

All you need to do is to find a list of service modes for TVs...
Click to expand...
TV's have service-modes? I should have checked. What kind of stuff can
you do? Shouldn't ask. I hear it was once possible to get a CGA monitor
to self-destruct by switching the scan rate to a frequency the flyback
power system couldn't handle.

--
Scott

**********************************

DIY Piezo-Gyro, PCB Drill Bot & More Soon!

http://home.comcast.net/~scottxs/

**********************************
 
Scott Stephens <scottxs@comcast.net> wrote:
Ian Stirling wrote:

All you need to do is to find a list of service modes for TVs...

TV's have service-modes? I should have checked. What kind of stuff can
you do? Shouldn't ask. I hear it was once possible to get a CGA monitor
to self-destruct by switching the scan rate to a frequency the flyback
power system couldn't handle.
Click to expand...
Many do, yes.
It's become cheaper to put many of the controls in software, rather
than as little twiddles on the board, especially as you have to
pay someone to twiddle them, but you can do some of the alterations
automatically.
Some TVs are probably self-destructable, and some are effectively so,
as they can be made to not work, even though if someone knew how
to fix it, they could.
 
Scott Stephens <scottxs@comcast.net> wrote:
SampleBandit wrote:

Howdy all,

I am building a simple tv remote jammer

You nasty mean little punk. Don't you have anything better to do ;)

using the simple 555 timer
chip. I don't want to get as extreme as a microcontroller.

Lazy-ass. Learn how to program PIC's. They are delicious and nutritious.
snip
Better yet, rip-off somebodys code for a PIC. Program the PIC to be
REALLY mean and obnoxious, making the TV randomly change channels and
turn on and off every three or four minutes. Better yet, make the
channel-change interval random too.
Click to expand...
All you need to do is to find a list of service modes for TVs...
 
Okay look.

I have no intentions of destroying the TV, I just want to keep one
person from using the remote as they are abnoxious and turn the volume
up loud and continously flipping channels. I just wanted something
simple. Lazy? Program PICS? Nah... I'm
an AVR guy. Got a stockpile of them and an STK-500. I have made
circuits that not
only create the individual IR codes but that have also recieved the
signal through a module and had enough intelligence to determine tv
remote brand and ir transmit scheme. Again, I just wanted ro be
simple. Since a couple of people here have suggested the modulation of
the IR carirer frequency, I will try that this weekend by adding an
additional 555 (or maybe 1 556) and AND both signals together. Of
course this method would not create random modulation duty cycles but
it is worth a try. If it comes down to it, I will stick an AVR on the
board and flash it with some code I have already written. An AT90S2313
would be a perfect AVR for the job.
I could not only create random modulated duty cycles then but also
random carriers between the 36-40khz range and then have it work for
most all TVs. I would hate to do all of this just to find out that I
am back to distance range problem again.

The most simplist thing that could be done is to stop the one
abmoxious person but its not my TV which has led to this project.
Simply asking the person not to do it has no results either. I am not
doing this to be a prankster but for peace of mind. I know that if the
remote doesnt work for him, there is no way he going to get up off his
fat ass to walk over to the tv and change the channels manually.

Anyway from what it sounds like so far, maybe my range is fine but my
signal need to be more sporatic and random. Thanks all for the
comments so far.

Bob
 
SampleBandit <bschumann@thompsonpump.com> wrote:
Okay look.

I have no intentions of destroying the TV, I just want to keep one
person from using the remote as they are abnoxious and turn the volume
up loud and continously flipping channels. I just wanted something
simple. Lazy? Program PICS? Nah... I'm
Click to expand...
Earplugs.
 
"SampleBandit" <bschumann@thompsonpump.com> wrote in message
news:c274917c.0405210327.32be5ef5@posting.google.com...
Okay look.

I have no intentions of destroying the TV, I just want to keep one
person from using the remote as they are abnoxious and turn the volume
up loud and continously flipping channels. I just wanted something
simple. Lazy? Program PICS? Nah... I'm
an AVR guy. Got a stockpile of them and an STK-500. I have made
circuits that not
only create the individual IR codes but that have also recieved the
signal through a module and had enough intelligence to determine tv
remote brand and ir transmit scheme. Again, I just wanted ro be
simple. Since a couple of people here have suggested the modulation of
the IR carirer frequency, I will try that this weekend by adding an
additional 555 (or maybe 1 556) and AND both signals together. Of
course this method would not create random modulation duty cycles but
it is worth a try. If it comes down to it, I will stick an AVR on the
board and flash it with some code I have already written. An AT90S2313
would be a perfect AVR for the job.
I could not only create random modulated duty cycles then but also
random carriers between the 36-40khz range and then have it work for
most all TVs. I would hate to do all of this just to find out that I
am back to distance range problem again.

The most simplist thing that could be done is to stop the one
abmoxious person but its not my TV which has led to this project.
Simply asking the person not to do it has no results either. I am not
doing this to be a prankster but for peace of mind. I know that if the
remote doesnt work for him, there is no way he going to get up off his
fat ass to walk over to the tv and change the channels manually.

Anyway from what it sounds like so far, maybe my range is fine but my
signal need to be more sporatic and random. Thanks all for the
comments so far.

Bob
Click to expand...
Hi Bob,

look at the data sheet of IR receiver devices like the TSOP2238 (I just
designed one into a product) - it will show you why Mike and Scott
suggestions will help (agc etc). As Scott mentioned, find an emitter that is
the exact right wavelength. You can beat the hell out of leds, and yes they
get hot, but so what - just look at Tjmax and dont exceed it. Make sure your
driver has fairly square edges too - perhaps it cant really handle the
36kHz - T=28us so for a decent edge, you want to switch in around 1us, which
should be achievable - I do 600ns switching at 50mA with a BC847....

Cheers
Terry
 
mv /var/posts/Scott Stephens/scottxs@comcast.net /dev/null:
Ian Stirling wrote:

All you need to do is to find a list of service modes for TVs...

TV's have service-modes? I should have checked. What kind of stuff can
you do? Shouldn't ask. I hear it was once possible to get a CGA monitor
to self-destruct by switching the scan rate to a frequency the flyback
power system couldn't handle.
Click to expand...
You can change a lot of settings and the TV *may* work [1] - read this as "You
can f*ck the TV so badly".

[1] Some TV's go "suicidal" when you change certain settings in the service
menu.

Do not try this at home, kids! :) <g>

[]s
--
Chaos MasterŽ | "I'm going under,
Posting from Brazil! | drowning in you
ICQ: 126375906 | I'm falling forever,
ask for e-mail/MSN | I've got to break through"
---------------------. -- Evanescence, "Going Under"
 
SampleBandit wrote:

Okay look.

I have no intentions of destroying the TV, I just want to keep one
person from using the remote as they are abnoxious and turn the volume
up loud and continously flipping channels.
Click to expand...
You might be able to "condition" this person to behave, Skinner or
Pavlov style, in an indirect "passive aggressive" mode.

The idea is to manipulate the target suppress his behavior with his
awareness of being controlled.

1. Make a "signal" behavior, such a a strange cough, a phrase, a sound.
Something new, but not too noticeable. A stretch, cracking your
knuckles, et.

2. Link the signal behavior to the offenders behavior - changing
channels in this case.

3. Create a punishment response - Leaving the dishes unwashed, being
crabby, trigger a 400 watt concealed ultrasound generator, et.

4. Link the punishment response to the signal behavior.

I don't advocate mental cruelty. A short time after your "lessons" sink
in to the target, they will probably become passive-aggressive in turn.
But some people and institutions are too self-centered to be reasoned with.

--
Scott

**********************************

DIY Piezo-Gyro, PCB Drill Bot & More Soon!

http://home.comcast.net/~scottxs/

**********************************
 
On Sat, 22 May 2004 08:42:32 GMT, Scott Stephens wrote:

SampleBandit wrote:

Okay look.

I have no intentions of destroying the TV, I just want to keep one
person from using the remote as they are abnoxious and turn the volume
up loud and continously flipping channels.

You might be able to "condition" this person to behave, Skinner or
Pavlov style, in an indirect "passive aggressive" mode.

The idea is to manipulate the target suppress his behavior with his
awareness of being controlled.

1. Make a "signal" behavior, such a a strange cough, a phrase, a sound.
Something new, but not too noticeable. A stretch, cracking your
knuckles, et.

2. Link the signal behavior to the offenders behavior - changing
channels in this case.

3. Create a punishment response - Leaving the dishes unwashed, being
crabby, trigger a 400 watt concealed ultrasound generator, et.

4. Link the punishment response to the signal behavior.

I don't advocate mental cruelty. A short time after your "lessons" sink
in to the target, they will probably become passive-aggressive in turn.
But some people and institutions are too self-centered to be reasoned with.
Click to expand...
And god saw that the shotguns were good...
--
Best Regards,
Mike
 
Activ8 wrote:

I don't advocate mental cruelty. A short time after your "lessons" sink
in to the target, they will probably become passive-aggressive in turn.
But some people and institutions are too self-centered to be reasoned with.


And god saw that the shotguns were good...
Click to expand...
LOL - machetes & rolling pins too! I've heard there's nothing like
inflicting blunt-force trauma to relieve your pent-up frustration and
rage :)



--
Scott

**********************************

DIY Piezo-Gyro, PCB Drill Bot & More Soon!

http://home.comcast.net/~scottxs/

**********************************
 
On Mon, 24 May 2004 22:47:20 GMT, Scott Stephens wrote:

Activ8 wrote:

I don't advocate mental cruelty. A short time after your "lessons" sink
in to the target, they will probably become passive-aggressive in turn.
But some people and institutions are too self-centered to be reasoned with.

And god saw that the shotguns were good...

LOL - machetes & rolling pins too! I've heard there's nothing like
inflicting blunt-force trauma to relieve your pent-up frustration and
rage :)
Click to expand...
Yes, but no weapon at all can be quite satisfying, also :) Try it
some time. No. Hey. If you can't get off on a punching bag, try a
good martial arts school. Rigorous sex with a female works too, and
sex after dojang is even better.
--
Best Regards,
Mike
 
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