Electronic Candle Protects Sleeping Infant

[William] developed this temperature candle as a tool to help keep babies safe as they sleep. It seems that ambient temperature has an effect on Sudden Infant Death Syndrome (SIDS). This device is meant to alert you when room temperature is outside of the recommended envelope.

The board hosts an eight-pin PIC microcontroller (12F683P), a temperature sensor, RGB LED, and a push button. The round PCB is the same size as a votive candle, which is nice except that you’re going to have to drill a hole in your candle holder to accommodate that barrel jack.

The temperature sensor is read by the microcontroller and used to determine the color of the LED. Red is hot, blue is cold, and just right is somewhere in between. But if you’d rather know the exact current temperature you can press the button and it’ll blink out the Celsius reading using blue for 10 degree increments (three blinks is 30 degrees, etc.) and red for single degrees. Don’t miss the demo of the candle in the video after the break.


31 thoughts on “Electronic Candle Protects Sleeping Infant

  1. This is one of those perfect uses of open source hardware…something that is valuable and might be able to help save lives, but would never be marketed because the possible profit is not worth the liability.

    Awesome job!

  2. That is pretty cool. I have a four month old and might have to do a similar project… I am more versed in AVR’s so I might have to use that instead.

    As for liability, I think you can skirt it with a EULA, or make sure you aren’t marketing it as “Prevent SIDS” with this device. I think it would be ideal if marketed as a simple temperature monitor.

  3. So, what, will they have a camera trained on it at all times? Does it have an audible alarm if the temperature is too far off? Or are the parents supposed to watch this thing all night?

    1. Since the developer doesn’t say, I’ll assume there aren’t any major temperature gradients in the home, and the ‘candle’ stays with the caregiver. Since there’s no audible alert, someone has to be awake. I suppose a buzzer is left as an exercise for the hacker.

  4. So this is a visual indicator of the temperature?

    Why not just put a thermometer on the wall? No power, more reliable, extremely simple, cheap…

    To go a step further, why not just install a thermostat to automatically keep the temperature in the range? No need to be alerted and manually change the temperature.

    Am I missing something? This seems like a solution to a problem that doesn’t exist…

    1. I would think most people would have a thermostat. It’s assumed you have one actually… the temp range he talks about is only 4 degrees Celsius.

      Obviously this is only meant to give the parents peace of mind because SIDS is a pretty scary thing and a common worrying point of parents with infants.

  5. Why would you want to base it on the mcp9701 temperature sensor from the microchip? It has an accuracy of +-4 degrees. I would rather have chosen the DS18B20, then I would also save a voltage reference.
    And would it not be easier to read a 7-segment display?

    1. Agreed! The range he states for room temp is 16°C – 20°C (60.8°F – 68°F), which is only 4°C range! :)

      This is fairly practical indicator… and a nice reassurance.. but I wouldn’t bet my baby’s life on it. Obviously the code should be written in such a way that it is bullet proof. Brown-out reset voltage should be set just below nominal range of acceptable voltage for the clock speed you are running at. This will reset the uC if the power dips to a voltage that can cause RAM/FLASH corruption. I would also set a watchdog timer detect for improper code execution and one more software timer to hard reset the uC every 60 seconds or so just in case… if that PIC has the capability of invoking a software reset. Upon power up clear all RAM and reinitialize everything. The constant resets won’t hurt anything visually.. especially if you make it flicker off occasionally. I don’t know if it’s flickering because the camera or if that was intentional… but I would make it flicker on purpose to distinguish between locked up code and normally running code. You could put redundant temp sensors on the board and poll both to make sure one hasn’t failed. Just some ideas ;-)

    1. They do have a string of ‘share’ buttons, just after the YouTube video. But I agree. A ‘like’ button would be easier. :)

      That said, I really like this monitor design. So simple, but so damn effective, i.e. elegant. You’ve got a winner here, William. Tip of my hat to you, sir.

  6. There are wired/wireless thermometers that gives much more accurate readings and display on a LCD without the hazard of power cables.

    You can also repurpose a programmable thermostat for alarm purpose. Just saying…

  7. @macegr these units could be made and improved and sold for profit. just make sure you point to the llc part of your sign and say “sorry you are only getting $100 from me if you sue”

    actually nothing is a substitute for good parenting even a gun lock (for those with firearms and kids who may have access to the guns)

    i thought sids was caused by babies rolling over and smothering them self in the pillow or forgetting how to breath and hold their breath until sids kicks in.

  8. Overpopulation of the planet is a fairly reasonable point, but a tad insensitive and not really applicable to the individual with a child, more to society as a whole.

    Here’s a rather interesting series of lectures, if you have 90 mins to spare:

    However, these light indicators already exist for this purpose, though they are rather expensive for what they are!

  9. I rather thought these were an alternative to a thermometer. Thermometer requires you to know the safe range and go through an algo in your head. The coloured led is relatively intuitive and can be assessed at a glance. I do realise reading a thermometer isn’t exactly difficult, but still.

    I know, it had been so good for the last few months, but it would appear the trolls have found their way back. HAD needs to lay smackdown again.

    1. How about covering up all but the “good range” of temperatures on a thermometer with tape?

      If you can see the end of the indicator, all is good, otherwise the temp is out of range. That should take all the “guess work” out of reading a thermometer, but honestly if you can’t read a thermometer to begin with, SID is probably the least of that child’s worries.

      If you’re goal is to have a reliable gauge for a temperature range, there are many better/easier/cheaper/more reliable ways than building this contraption. Isn’t a hack supposed to improve something somehow? This seems like a downgrade in every way I can think of… not to mention the other comments saying the margin of error on the chosen temp sensor is larger than the safe range to begin with.

      With a couple glaring exceptions, I don’t think trolling is a problem in this thread. People are pointing out the problems with this “solution”.

  10. I think this might give people a false sense of security. Room temperature- as long as you don’t obviously feel that it’s way too hot- is not one of the prime correlates for SID. By puttin this up people will concentrate on it “showing the green light” and think everything is fine. But sleeping position, pillow use and especially the smoking habits of the parents are orders of magnitude more important. And in the end- sometimes you just can’t do anything. A friends baby died of SID even with a breathing monitor mattress. It stopped to breath and although everything was done to safe the child it died. A little room temperature monitor is snake oil and provides a false impression of security.

    1. I’m sorry to hear about your friend’s situation.

      I would suggest this device is just one more thing a parent can do to help ease their mind… but a parent’s mind is never without worry, especially with an infant. I’m pretty sure no parent would actually get one of these and think that’s ALL they had to worry about. Nope. Not in the least.

      Personally, if I had one of these… I would most definitely hold my finger on the temp sensor every time I checked it to see if it would warm up a bit and show RED… then settle back down into the WHITE.

      You try to do everything you can to protect your kids… this is a cool project.

      Lastly, I think it wouldn’t even get a second notice if it wasn’t associated with SIDS… it really IS just a temperature sensor. So no one should presume it’s supposed to be a life saver.

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