infrared sensors / detectors

Discussion in 'General Electronics Chat' started by ezzo, Feb 13, 2016.

  1. ezzo

    Thread Starter New Member

    Feb 13, 2016
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    Hi, I need help by someone who is very knowledgeable with infrared sensors / detectors etc. I have bought a sleep mask that can detect when a person is in REM sleep (dreaming) The sleep mask has a small circuit board inside with an infrared detector that detects eye movementthroughout the night.

    When the infrared detector picks up a lot of eyeball movement it then knows the person is dreaming and will flash 2 bright LED lights at the closed eyes allowing the dreamer to know when they are dreaming. The device is acurate and does what it says 'on the tin' Anyway, my issues are as follows. I am concerned that all night i have a electronic sensor constantly monitoring my eye for movement.

    The reason this is a concern is that it could damage the eye / long term problems etc. Im no expert but having infrared detector / device 1mm from the eye all night could be dangerous?

    This is a passage from their website ........... "The REM-Dreamer uses infrared sensors to detect when you are in REM (dreaming) sleep. At that point the REM-Dreamer gives you sound and light cues (beeps and flashing lights) to remind you that you are dreaming. Thus, external world stimuli are transferred to the world of your dreams, and it becomes easy to achieve lucidity"

    Please take a look at their website to get full details on this device, thanks you

    RemDreamer description - http://remdreamer.com/index.php
    Rem dreamer photos - http://remdreamer.com/rem-dreamer_pro.php Thank you Terry
     
  2. Alec_t

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    Sep 17, 2013
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    I can't tell from the info in that desription, and the pics, whether the IR sensors are active or passive. If passive then there would be zero risk of damage from IR irradiation. Personally, I'd be more concerned that the gizmo would be mucking about with Mother Nature's way of organising/refreshing the brain during sleep. Could that have long-term consequences for memory?
     
  3. ezzo

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    Feb 13, 2016
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    Hi. when dreaming, retrospective memory is largely switched off, this is why when you are dreaming of riding a green dragon whilst the small bushes are firing apple at you, it all makes sense within the dream (because when dreaming you dont actually remember enough waking life details to realize that dragons and apple firing bushes dont actually exist - this is why dreams make sense however bizzare) This is why there is no risk to waking life memory ... anyways :) - How can I find out if the sensors are active or passive. Is there something I can view on the device to help? Thanks
     
  4. tracecom

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    Apr 16, 2010
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    That is a very interesting gizmo...and more than a little pricey.

    In looking at the photo of the PCB, I see the LEDs that presumably flash during REM (although I suppose they could be IR LEDs), but I don't see any other sign of LEDs. If you can get the PCB out of the mask and power it up, you can look at the face side through a digital camera and see if there are IR LEDs shining.

    ETA: I would worry about the visible LEDs being that close to my eyes.
     
  5. tracecom

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    I just now looked at the photos you attached. It looks like there is an IR emitter in addition to the IR sensor and the visible LED. I think you are right to be cautious.
     
  6. ezzo

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    Feb 13, 2016
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    Hi again, do you think LED's that close to closed eyes would be a problem then? What would the risks be? I can take the whole circuit board out of the mask to check, would my iphone camera be sufficient to check?
     
  7. tracecom

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    You don't have to take the PCB out. Look at the photo you posted. Just above the visible LED is the smaller IR emitter. Yes, you should be able to see that with your I-phone.

    LEDs can be far too bright to even look directly into for any period of time. Personally, I would not want any light sources directly in front of my eyes for hours at a time...at least not without knowing a lot more about their intensity.
     
  8. DNA Robotics

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    Jun 13, 2014
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    Assuming you don't sleep with your eyes open, I don't think much light would get through your eye lids.
     
  9. ezzo

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    Feb 13, 2016
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    Hi, when the lights go on, they very quickly flash for just a quarter of a second spaced over 2 seconds total and then they circuit switched off, so they, in total flash quickly 4 times spaced over 2 seconds and this happens maybe 4 times per night so the total time that the LED would be lit up over the course of a night would be 4 seconds ish. The eyes would also be closed during this time.

    Its the IR emitter that concerns me. Any furthur advice would be very welcome guys :)
    Also i looked at the sensor via my iphone and it just looked the same, no lights or anything
     
  10. tracecom

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    I am just guessing, so don't think I have any expertise. It's possible that the IR emitter is just pulsed briefly and the IR sensor turned on at the same time, and the pulse is too short for you to see. Perhaps the manufacturer would supply some information if you asked regarding light intensity and frequency from both the IR emitter and the visible LED.

    I watched a you-tube video that showed a couple of guys that had a circuit that detected eye movement via three sensors on the forehead. That seems a lot less intrusive than IR in the eyes.
     
  11. ezzo

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    Feb 13, 2016
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    Yes that sounds like the upcoming Aurora https://iwinks.org/
    They use EEG to detect rem sleep brainwaves and eye movement. They will not be using IR emmiters but EEG to alert someone when they are dreaming. I hope EEG strapped to the head all night is safe
     
  12. AnalogKid

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    Since those are not thermo-voltaic piles, such as a bimetal thermocouple, those are active IR sensors. Probably photo diodes or photo transistors. These usually are biased with DC, so there are no radiated RF fields. The only potential for eye damage comes from the LEDs, assuming the LEDs are not stupidly-bright...

    ak
     
  13. tracecom

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    You did notice the smaller device just above the LED in the photo in post 1, right? And don't you think it's an IR emitter?
     
  14. tracecom

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  15. ezzo

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    Feb 13, 2016
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    If it helps, when i put the mask on in test mode, i can lay there and whenever i look left right up or down the mask lets out a little beep to let me know the device is working properly.

    AnalogueKid: You answer is way above my understanding of terminology, can you rephrase what you are saying in more laymans terms please. Also the LED have 10 brightness settings and dont seem that bright with eyes closed, more 'just comfortable'
     
  16. AnalogKid

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    There are two kinds of IR sensors, a) ones that generate a small current like a tiny battery, and b) ones that alter current flowing through it from an external source. In general terms these are thermocouples, photodiodes, and phototransistors. In all cases there is no radiated radio-frequency energy, something that could damage the delicate tissues of the eye.

    ak
     
  17. ezzo

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    Feb 13, 2016
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    Hi again Guys. So would you say this device is safe to use. The LEDs that flash look like normal yellow LEDS, they are not too bright and only flash for less that half a second twice so Im not concerned about the LED's

    What concerns me (as a non technical) person is the emitter and sensor. What happens is that the mask detects my eye movement so if i look left or right, up or down then it records that movement and if i make lots of eye movements within a period of 30 seconds then the mask determines that im dreaming and will flash the leds very quickly

    From my perspective (and this may sound a bit stupid) I know that i have something that is constantly monitoring my eye movement and im worried that whatever is doing that monitoring (the ir sensor / emitter) may cause damage via radiation or something. I dont want to damage my eye.

    Any advice would be very welcome and thanks in advance
    Ezzo
     
  18. ezzo

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    Feb 13, 2016
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    This is the reply from the manufacturer when i asked if the ir was passive or active

    "It is active. Infrared which we use is very close to red light. Red light is safe and infrared is even more safe than red light becouse eye doesn’t see infrared. Pupil doesn’t react with infrared. So that’s why it is 100% safe.
    We have been selling REM-Dreamer for 12 years and we didn’t have even one customer who said that it did damage to his eye."
     
  19. tracecom

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    I agree with part of what the manufacturer told you: it is active. That small LED that I circled in the photo above is almost certainly an IR LED.

    The human eye does not react to IR, but that does not mean IR is safe. IR has a higher heat component than visible light. So, logic would indicate that IR is potentially more dangerous than visible light for the following reason. If the human eye doesn't see and doesn't react to IR light and if IR light has significant heat, then the human eye (retina) could be burned without the eye reacting by blinking or contracting the pupil.

    However, they probably wouldn't stay in business long if the product was damaging people's eyes. Personally, I wouldn't use it, but that's just my cynical nature. I wash my hands after I shake hands whenever possible.
     
  20. Dodgydave

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    If your dreaming of riding dragons and having apples thrown at you, i suggest you get back to doctors and get some stronger sleeping tables...o_O
     
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