9v IR Tester

Whenever you are working with infrared, you sometimes need to see it, and thats kind of hard. Most people would jump up and say “camera”, but that is not always the best solution. For instance my phone camera is so filtered its near useless for IR, and my DSLR will only take a full blast source and present a dim glow. Wanting something a bit easier [Candymanproducitons] whipped up a little IR tester that fits on top of a standard rectangle 9V battery.

A simple circuit containing nothing more than a LED, resistor, and a IR photo-transistor was assembled on some perforated circuit board, then mounted on top of a battery clip with some epoxy. The end result is a compact and robust tool that will be very handy in the shop, though we think a little spot for your scope probe would be super.

9 volt batteries, with their internal design and locking / polarized terminals are usually a mainstay of electronic tinkerers, and often pop up in cool and compact projects like my lm386 amp in a battery shell from last year. So what can you do with them?

Comments

  1. Hitek146 says:

    Wow. I’ve never done this before, but this is just too much…

    “its near useless” = “it’s near useless”
    “a LED” = “an LED”
    “a IR” = “an IR”
    “rectangle 9V” = “rectangular 9V”

    Cool project, though. I did something similar back in ’95 to detect the presence of light on fiber optic cables feeding CATV nodes. This is a very useful tool in the proper situation. Well done…

  2. Dave says:

    @Hitek146, actually “a LED” is correct.

    Good thing this is the first time you’re doing it.

    Let’s hope it’s also the last time.

  3. Till says:

    Nice simple tool but there are also little plastic cards called “IR Detection Cards” glowing green if hit by an IR-source.

  4. Cricri says:

    “a LED” = “an LED”
    Erm, that’s just you then. And if you’re going to be anal, it should be a parallelepipedic 9V battery and not a rectangular one.

    Now that we’ve pointlessly, yet pedantically, argued semantics, my opinion: I’m not into IR myself, but neato anyway. Could it be done with a AA clip since 9V batteries are not cheap?

  5. don't care says:

    If you’re going to be shallow and pedantic, be correct.
    LED has an “ell” sound at the beginning.

    Otherwise, cool project.

  6. Bacchus says:

    Or just use the rubbish camera on your phone – They always seem to work.

  7. krylenko says:

    Actually, the choice of “a” vs. “an” is determined by the sound of the first syllable, not the actual letter.

    “LED” = “el ee dee” and since that begins with a vowel sound, “an LED” is correct.

  8. CrashSerious says:

    Holy grammar police hijacking batman!

    Lets get back on topic here… This is a really handy hack.

  9. K!P says:

    but led is short for Light Emitting Diode that would make a LED correct…

  10. Elias says:

    But the abbreviation is Light Emitting Diode, so which one to use, the letters or the full version :)

  11. Smokingman says:

    Technically, LED is an initialization not an abbreviation because it’s not pronounceable.

    i.e.
    SCUBA = abbreviation
    LED = initialization

  12. alan says:

    I say it as L.E.D. (individual letters) so in normal conversation I would say ‘an’ L.E.D. because, obviously, this sounds correct. Saying “a L.E.D.” makes you sound like a 5 year old.

    However, I work for an electronics company where most people pronounce it “led” as in “Ted” or “bed”. In these cases, they say “a led” because the other way sounds stupid, obviously. (anled?).

    So I guess it depends how you pronounce LED.

  13. Ren says:

    nice hack, but since a[n] LED can also be used as a photo-transistor, maybe…
    B^)

  14. Olivier says:

    Ouch! 9V battery aren’t rectangular nor parallelepipedic, they have “rounded edges”. So, well, let’s say it’s a 9V battery with a weird shape.

    Oh, and for the LED, let’s write it in french : “une DEL”.

    @Bacchus: nope, the author has a crappy phone camera which filter IR.

  15. NatureTM says:

    Beautifully simple. Nice hack.

  16. Patrick Dent says:

    @Olivier So it’s a rounded-rectangular prism 9v battery?

  17. James says:

    Not really a hack. And I’ve never met a phone camera that didn’t work, but it’s nice and simple and works, so thumbs up anyway.

  18. sh0cked says:

    I have never met anyone who uses the separate letters L E D when spoken. Its usually led (like ted bed fed red). Whoever said it is not pronouncable doesnt speak english.

  19. Alan Yates says:

    Nice simple and useful hack, I love 9 volt battery-topper projects for quick hacks.

    I use a solar cell and a piezo sounder myself, but that only works with modulated sources; fine for IR remote controls. This phototransistor based device can in principle detect CW IR sources and those modulated at high frequencies.

  20. Hirudinea says:

    I don’t know the range of this thing, but refering to what Alan said, if you replace the LED (a, an, um, ah f–k it) with a piezo buzzer and hide it somewhere in a persons desk where they can’t see it but you can shine a remote control at this could be a fun little prank.

  21. wernicke says:

    actually, SCUBA is an acronym (Self Contained Underwater Breathing Apparatus). ‘Abbr.’ is an abbreviation.
    Nice project.

  22. DarwinSurvivor says:

    @sh0cked And I have never (until now apparently) met anyone that DOESN’T pronounce each letter individually. I guess it all depends on where you live.

  23. aad453 says:

    If one were to replace the led with an ir diode, could this be used to “bounce” a remotes signal around a corner?
    Im guesing it would work but the ir emmiter might cause feedback from the beam reflecting around the room and coming back into the sensor. what do yall think?

  24. Drone says:

    “…fits on top of a standard rectangle 9V battery.”

    Man, what planet are you from? One that presumably has mainly cylindrical 9V batteries?

  25. D_ says:

    I’m going to go to the local hardware store and ask them for a prismatic nine volt battery. That place is so old they just may drag out a battery of the strange kind that where used in the first transistor radios, or used in the old tube type portable radios. I do remember some of my older cousins using those tube radios.

  26. vtl says:

    If youre working with IR you can get a cheapo Canon compact camera and remove the IR filter. Being able to see the actual IR light beam pattern and distance would be more useful than just this repeater thing.

  27. Grovenstien says:

    9v batteries come in a myriad of different shapes and sizes, i think that this article refers to the PP9 type!

    Man i love to lick those little terminals until my tongue tickles.

    Also plug two PP9 together! KABLAMO!

  28. Hitek146 says:

    “@Hitek146, actually “a LED” is correct.

    Good thing this is the first time you’re doing it.

    Let’s hope it’s also the last time.”

    If by “doing it”, you’re referring to my pronunciation of L.E.D., then I have been “doing it” since the ’70s. Only younger generations say “lead”. I guess the DSLR referred to in the article should be pronounced “disler”???? :)

  29. rlachenal says:

    IR is also visible on your mobile-phone/video camera so you can also use that for detection.

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