The TV-B-Gone flashlight build

Flashlight Modding and DIY Parts
22

Update:

Software’s 100% done/tested on my AVR Dragon. Using an ordinary through-hole IR LED, it’s happily turning off my living room TV.

So I put the flashlight together, and it turns out the LED’s cathode is connected to the heatsink pad on the bottom… probably should have made sure first that it was isolated. End result was a direct driven LED with a 1.3V forward voltage. LED’s blown.

I have PCBs I can mount the LED on, but the LED+PCB combo is too thick for the pill/reflector to thread together. I’m starting to think that P60 wasn’t the ideal form factor for this project.

23

Use just one layer kapton as insulating.
Or use thermal compound glue this insulate too.
I have often seen that some guys glue the LED with a small amount of thermal glue on a piece of hampackage or with similiar clean smooth surface. After that it is totally covered with non insulating material…

I had a p60 p7 dropin and there was the Pill than kapton than big drop of thermal grease…

Have you spare LEDs or do you have to wait 5 weeks for another package?

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I’ve got two spare LEDs. Bought the parts to build 3 of these things, knowing full well I’d mess one up somehow :slight_smile:

I’ll probably do the kapton thing. The LED doesn’t dissipate that much power - it’s getting driven by 2.8A at about 1.3V, and the duty cycle’s only about 20% outputting codes. So less than a watt of dissipation.

Once I get this design tested/perfected, I might try and find a LED star capable of holding an Osram SFH4725S. More expensive but the IR output power is about the same, and it’s in a better package for flashlights than the 5 chinawatt DX special.

25

I wonder if the arrival/departure screens at air ports work on remotes.

That could cause a lot of problems.

26

Alright Tyler Durden…don’t give TSA any reason to target us :stuck_out_tongue:

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Not the intended use of this thing, and hopefully they’ve thought of that.

Most recent TV I turned off was in a department store, playing an “eggies” ad.

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GMarsh - Don’t spend your spare time hanging with the Giz Giz crew do you? :wink:

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Action shot! The video looks purple because I’m using a camera with the IR filter yanked.

I decided to omit the kapton tape and just glue the IR emitter directly to the pill with Arctic Alumina. I used a thick layer and managed to keep the base isolated. I’m cleaning up the AVR code now to share it.

30

Nice work, so is there any visible light at all when it is on? It seems like I would accidentally leave it on all the time...

31

Adding a constant mode for saturating IR motion detectors could also be fun…

32

When TV codes are finished sending, the microcontroller powers down and current draw is about 250uA. You’re safe for a while if you leave it on.

The flashlight ‘chirps’ very quietly when it’s sending codes - if you hold it up to your ear and click the switch, you can tell whether you turned it on or off by listening for it. Or you can check it by looking at the light with a cellphone camera.

33

This is cool.

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It won’t affect them in any way. Motion detectors work on a much longer wavelength/different principle.

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Passive IR motion detectors primarily see at much higher wavelengths, over 5µm (5000nm). Other wavelengths are cut out by a filter window but perhaps enough can still get through. Some datasheet show 0% below 4µm but I’ve also read a report of a high power IR 940nm illuminator reducing the sensitivity of a PIR detector.
Always worth a shot.

36

gmarsh, I like this (and not for anything malicious or illegal!)

Any thought given to selling a finished dropin for P60s? Or is there so much hand-assembly and fiddling that you couldn’t make it at a decent price point?

37

Materials used to make the P60 pill:

- Nanjg 105C ($3.50 at DX)

- P60 pill/reflector set ($2.20 at DX)

- DX “5 watt” 940nm IR LED ($6.03 at DX)

- Microcontroller/ceramic resonator ($2.37 + $0.44 + 15% tax)

  • Solder/wire/Arctic Alumina/etc, say $2 worth

Or about 17 bucks. There wasn’t much work involved, probably 1/2 hour total, to finish the construction of one so I’ll say I’ll sell one for about 30 bucks. I ordered the bits to build 3 - I blew 1 led, I’ll keep 1 myself and I’ll sell one.

I’m now looking at a different LED (Osram SFH4725S) which is better than the 5W LED in pretty much every imaginable way except continuous current handling. If I actually make a “sell a few of these to people” product for people, I’ll go with that LED - just need to find a 16mm MCPCB for it.

38

Interesting build.

I beg to differ on the psychological aspect, though. Turning off the TV is probably not the best way to calm down a bunch of drunken sports enthusiasts

39

I’m possibly interested in buying one if you go through with it.

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Agreed, but I think it’s an effective means of getting even with them :wink:

I’m building my second TVBG P60 module this afternoon. Assuming it works, I’m selling it in a blue WF-501B body for $35 CAD, shipping not included.

41

Second P60 module built/tested/working. Not tested on an actual TV (yet…), but the IR LED’s flashing away as it should.

I’ve got a PM from someone who wants just the P60, I’d rather flog it with the WF-501B. Reason being I changed the spring from the stock Nanjg one to a different one so it would work with the stupid black “rivet insert” that’s in the 501. If the P60 faces a cell directly, the new spring could step sideways and touch something it shouldn’t, causing a shorted cell or damaged driver - the ‘rivet insert’ has a ridge that prevents this from happening. I’m also not the greatest fan of the 501, so this is a dumb attempt to get rid of it :wink:

Also got a PM from someone who wants a reprogrammed driver and nothing else. I’ve got a single spare one, I’ll PM you back.

After this, it’ll be a few weeks at least - I’m starting work on the Osram LED version. It’ll have at least 2x more optical output power, much better throw, and be much easier to build. I have to design/order PCBs and get LEDs, a couple new hosts to try, batteries, more drivers, etc. I’ll make a new thread when things are up and running again.