Making Sure A Baby Is Still Breathing With Lasers And A Wiimote

[Gjoci] just became a father, and to make up for not having to carry a baby to term he decided to make himself useful in another way. He developed a sensor to detect a baby’s breathing, allaying the fears of nervous parents who are wondering why their child is so quiet.

Unlike similar builds and products that rely on microphones or capacitive sensors, [Gjoci]’s build uses the camera from a wiimote to triangulate points of light and detect motion.

The build started off with infrared LEDs, but the batteries were big and there is always the possibility of the baby swallowing electrical components. [Gjoci] finally hit upon the idea of using small 1mW laser diodes to project points of light. This worked beautifully, and since newborns don’t move much there’s no danger of shining a laser into a baby’s eye.

The rest of the build is just querying the camera every few milliseconds and seeing if the position of the reflections captured by the wiimote camera have changed. In two weeks of operation, [Gjoci] only had to respond to a few false alarms, and the hardware hasn’t crashed at all.

After the break are three videos [Gjoci] put up for us that show a test of the breathing detection system, a demo of the alarm, and an example of the build in full operation. A very awesome build, and we look forward to this post being used as evidence of prior art in a patent dispute a few years down the line.




66 thoughts on “Making Sure A Baby Is Still Breathing With Lasers And A Wiimote

  1. “since newborns don’t move much there’s no danger of shining a laser into a baby’s eye”

    Let me correct that for you… “Since newborns don’t move much there’s only a relatively small chance of shining a laser into a baby’s eye. And your one-eyed child will probably forgive you one day.”

    1. Between your comment and the “Baby, Laser” tags, I laughed. I know is mean, but I agree with you.

      Furthermore, when would you know your baby is not a baby anymore? When he had eye surgery (I’m guessing he started moving too much).

  2. Wasn’t there a post on hackaday that used an algorithm that enhanced differences between two images. They managed to detect breathing/heartbeats et cetera using that method. Would alleviate the laser concerns I guess.

    Doesn’t negate that this is still a nice solution.

  3. Usually I am against any kind of negative criticism of anything that shows up on this site as I believe everyone needs encouragement to keep exploring their ideas. Unfortunately I must say that the use of lasers in this case is an awful idea. As a parent of two I can tell you that you never know when they will suddenly start rolling and shifting in bed. Both of mine did a fair bit of belly shuffling around the crib before they started rolling over.

    I love the concept but I would never risk my child’s sight by using lasers.

  4. i don’t see what all the fuss about putting untested things near cribs is all about, the lasers allow the device to be placed as far from the crib as possible.

    the only real danger here is the lasers. lets push the melodrama to the side, has anyone tested the blink response of a baby? just because they are slow and clumsy at a young age doesn’t mean they don’t have the same natural reaction to intense blinding light. at least he didn’t use lasers from a blu-ray recorder or whatever.

    proabably what would be easier would be a breathing mask to put on the baby with a short length of hose and a flow sensor on the end.

    that way you could get information about how much air the baby is breathing and so on.

    nice idea just for a breathing/non breathing though.

    1. Problem with baby’s is that they don’t have all body protection functions working. For example body heat control (sweating) is not working properly, and hot car is more dangerous to baby than older kid. What comes to blink response, it may work or not, but when you statically point laser to baby’s eye, it may be that after blinking baby starts staring laser? you newer can be sure. So I must say laser and baby is horrible idea. Breathing mask is not much better, soon baby has some tube around neck, or mask comes bit off from face and baby cannot breath at all. There are baby’s that are choked by rag or cat that comes to sleep on face.
      For this hack, maybe a webcam and high contrast blanket? Something looking like chess board?

      1. I don’t suppose you would use a blinding light, just a bright light.

        One could easily imagine gradually increasing the brightness of a light source and testing the visual response, i.e following a finger.
        short term detrimental effects would come before long term.

  5. Does a Kinect have the necessary resolution to monitor a baby’s breathing?

    A Kinect and accompanying PC may be overkill for such an application, but may be less intrusive and far less harmful to an infant’s eyes.

  6. What is the risk of crib death? For argument sake, take 1%. What is the risk of laser damage? Somewhere in the ballpark of 1%? 0.5%? I fail to see the clear advantage here.

    Is wife/MOB (mother of baby) on board with this? You would be better off thanking her for her nine months of gestation by doing all or most of the night feedings. Trust me.

      1. Yes, luckily it is lower especially with the back to back campaigns and other safety things added. Unless it’s a sanctioned device, I wouldn’t trust anything in my child’s crib. Ask a doctor.. they’ll tell you this device is dangerous.

  7. Turn the power of the lasers way, way down and use a bandpass filter for the wavelength of the diode over the camera. Or use eye safe wavelengths, about 1.5 micron. The camera ought to still be sensitive at that wavelength though the IR filter will need to be removed from the sensor.

  8. Besides the danger of laser, seems like an overkill to me. Since Wiimote is mentioned, why not just tape the Wiimote to baby’s cloth and use the accelerometer to detect breathing movement? Much safer to me.

  9. Since sudden death of infants is a condition where the breathing motion continues while the blood oxygen levels drop to brain damaging levels, this invention will not help in those cases. It will however help in those rare (existing?) cases where the infant dies and stops to breathe.

    What you need, good sir, is a blood oxygen meter.

  10. Great idea, I think I’m going to do something similar if I ever have kids, there definitely seems to be a lot of negativity around the lasers, this is a class 1 laser product outputting half it’s rated power (measured). The Maximum permissible exposure is unable to be exceeded at 1mW let alone ~0.5mW. Read the definition of laser safety on wikipedia –

    “A Class 1 laser is safe under all conditions of normal use. This means the maximum permissible exposure (MPE) cannot be exceeded when viewing a laser with the naked eye or with the aid of typical magnifying optics (e.g. telescope or microscope)”

    it goes onto say if a telescope with sufficiently large aperture is used there is a remote chance of danger, so just make sure you don’t tuck your kid in with her favourite telescope.

    Wiki is correct in this instance as verified on many other sites. The chance of the child’s blinking reflex being impaired + the child being able to orient itself to view the lasers + the child intentionally staring at the laser + somehow the laser causing damage even though it’s at half capacity and at full capacity would not cause damage is remotely slim so I think this guy has done adequate research into protecting his child and that the chance of eye damage is order of magnitudes less likely than SIDS (sudden infant death syndrome) there fore I commend him for this project.

    Happy hacking :)

  11. I had heard a few years ago that most lasers in the class with commonly available laser pointers were completely safe for human eyes and that for the most part the warning labels that appeared on them were largely overblown. Here’s one of the few references I can find to what I believe the study was (same scenarios, at least, eyes were to be removed due to cancer, but were otherwise still functional at the time of the test, no lasting blindness and no structural defects found upon dissection and examination):

    “”*” The following except is from this site ( {} and explains the damage to the retina (or rather, the lack of any damage) caused by exposure to a 5 mw laser pointer. The patients were scheduled to have their eyes removed to combat uveal melenoma. (Yeah, cancer of the eye. Pretty lousy.) The bold emphasis is mine.

    Continuous exposure was directed to the fovea for 1 minute, to the retina 5° below fixation for 5 minutes, and to the retina 5° above fixation for 15 minutes. Ophthalmoscopic evaluation of the cornea, lens, and retina and fluorescein angiographic studies of the retina were conducted before, 24 hours after, and 11 days after laser exposure in the first case; before and 86 hours after exposure in the second case; and before, 96 hours after, and 15 days after exposure in the third case. Other than transient afterimages that lasted only a few minutes, we were unable to document any functional, ophthalmoscopic, fluorescein angiographic, or histologic evidence of damage to any structures of the eyes. Transmission electron microscopic studies of retinal sites targeted by the laser pointers in the second and third cases revealed ultrastructural abnormalities in the outer retina and the pigment epithelium that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites.”

    With all of that, I’d say this project is *probably* safe, though it could be made safer by including an infra-red camera attached to a facial recognition system that would either kill or reposition the lasers if the infant’s face moved too close to the beams.

    Also, as far as I am aware, in cases of crib death, the mechanism that causes a person to wake, breathe with greater depth, reposition, etc. when carbon dioxide levels in the blood increase due to either a failure to breathe or suffocation, is under-developed and respiratory arrest may either occur first, in which case a breathing monitor would be beneficial, or it may occur later, but in either case, rapid response will provide a good outcome. Humans, especially newborns can last several minutes in full arrest before permanent damage sets in, and often with infants, the cardiovascular and respiratory systems will spontaneously restart with even a tiny amount of external stimuli after arrest has occurred, where in older children and adults full CPR may be required.

  12. And, also, probably the best option, if one were to seek to build a better crib alarm would be a O2 sat monitor. One could conceivably build a wireless monitor that you could tape to your infant’s chest, with a short and securely taped lead going down to a finger for the monitor. Under clothing, there’d be virtually no chance for strangulation, there’d be no tether from the infant to the crib, and if something DID happen, like somehow, something, be it the monitor or anything else became wrapped around the neck, or if a cat tried to assassinate your progeny, or anything else, your monitor SHOULD alert you when SpO2 drops below, say 97%. You could still take a leisurely walk to the kid’s room, unwrap the cat, wiggle the kid a bit and the O2 sats would return to normal almost instantly, long before actual respiratory arrest would occur, long before anything but slight discomfort and maybe a little light headedness would happen.

    Now, if someone invents a way to do O2 saturation from across the room, with no sensors in direct contact with a patient, that would be awesome (if it used lasers you could potentially do the whole facial recognition thing to track movements and prevent laser-eye scenarios if one were worried about such things).

  13. But, you know what’s best – just don’t put blankets, toys, crib bumpers or other loose objects in the crib and keep the ceiling fan on. When we had infants in the SIDS age range, that’s what we did. We dressed them in snug fitting pajamas, or did baby-burrito wraps with blankets so they couldn’t get out (but this stopped when they started getting out) and otherwise just kept the room warm, and kept air circulating with the ceiling fan. My theory, and I think it’s a pretty good one, is that when the air is still, or there are obstructions in the crib (especially non-breathing crib bumpers) a sort of “pool” of CO2 can form near the child. This is worse when the kid sleeps face down (so face up, always), when the mattress isn’t as firm as it should be, that kind of thing. The kid might create a little crater, or the crib bumpers sortof dam up the area and if the air doesn’t circulate sufficiently, the CO2 concentration in that little region of the room just goes up and up until the kid dies. If he had a normal response to increasing CO2, he’d at least move his head a bit and cause an air current to mix regular air with his CO2 pool and the situation would resolve silently, but current research suggests that this response isn’t present in some children.

    So, face up, no blankets (they won’t freeze to death, if they’re cold, they’ll cry until you do something about it, or they warm themselves up from all that crying, unless your heat gets turned off or something), no bumpers, no cutesy comforters, stuffed animals, any of that shit. Newborns do not GAF about fluffy things with giraffes printed on them when they’re unconscious and they can handle knocking their noggins on a crib’s siderails or getting an arm out or something, no more force than they’re able to propel themselves with. And circulate the air. Best bets for avoiding SIDS.

  14. I dont see the point of this device, so baby stop breathing, alarm goes off and what next, what
    an you do next, by the time ambulance comes irreversible brain damage is guarantee

  15. Or……… Go buy an Angelcare baby monitor that is already proven to monitor breathing! Also it monitors sound ( thresholds are configurable so you aren’t waking up with small sounds) in addition to temperature monitoring with threshold alarming high and low configurable!

    This idea is so stupid, that baby will be moving around in under a month (mine is), the lasers are made of FAIL

  16. WOW. Bad idea. How about we use humans to parent instead? like I dunno, checking on baby from time to time? I bet with this thing you’ll be getting enough false positives of not breathing you’d be checking in often anyway… or like someone said, a baby monitor is a better choice than this blindness waiting to happen. I know playing with electronics and hobbys is fun and all, but put down the soldering iron and take care of your kid!!! Geeesshhhh!

  17. I love the idea.. that is something to check if they’re breathing, but the execution isn’t ideal IMHO.

    Now give me a simple tension sensor around their chest to monitor breathing & bluetooth/wifi access to it.

    You’ll get some false positives of course, esp. w/ new borns. Their breathing patterns can be erratic.

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