Sadly, I have done this. I tore apart a perfectly good LuxPro 1 watt flashlight and crammed 3 different test LED's into it. Granted they were not 940 but they were 850nm. first test was 1 watt, kept frying it because 1 watt white is 3 volt where 1 watt infrared is 1.8, so I moved on to 3 and 5 watt versions. the 5 watt provided less range than the 3 watt because of the limitations of 3 AAA batteries. But in the end I found that older TV's were more responsive to 850, I could actually point the thing anywhere in the room and the TV reacted, but a lot of newer ones you must point right at as they have much better IR filters on them now, my weak little samsung remote with its 940nm LED could be pointed anywhere in the room but my MEGA ULTRA TV-B-GONE had to be pointed straight at it?... anyway to the point. The parts I used were actually less in numbers than any tv-b-gone schematic found online.
1 - luxpro flashlight
1 - attiny 85v (with lots of modified code for TV-B-GONE and steady-burn to use as IR flashlight)
1 - mosfet, key here is MOSFET, not transistor, much heavier capacity and no linear effect, just on or off more like a switch.
1 - ceramic oscilator
1 - mini dip switch
1 - current limiting resistor between the attiny and the mosfet.
Cram it all into the flashlight between the 2 circuit boards.
Final unit does NOT work through low-e tinted glass but DOES banned off lots of people in bars.
I just ordered the 940nm to try and beef up the effectiveness.
Oh, and it looks like i'm not the only one to try this, even this guy used a lux-pro style flashlight. and he has an actual circuit board where mine looks like a bad prototype.http://diy.elektroda.eu/latarkowy-tv-b- ... y/?lang=en