Pee-light Gives Guidance For Nocturnal Tinkles

This light is a rather dim LED module whose purpose is to give you a very small bit of illumination when using the restroom at night. If you rely on it instead of using the overhead lighting in the bathroom, you’ll be able to find your way back to bed with your night-vision undisturbed.

[Fred] built the project as a way to learn more about using MSP430 microcontrollers. The protoboard seen above has a pair of female pin headers designed to accept an MSP430-PIR board, which uses the low-power microcontroller to monitor a PIR motion sensor. The chip can be reprogrammed and [Fred] did just that, using the USB dongle side of the eZ430-F2013 dev stick. Now when the sensor detects motion the chip first checks the light-dependent resistor on the protoboard to see if it’s dark in the bathroom. If so, it switches on the LED and sets a timer to shut if off again.

The system runs on a 9V battery, which is a bit under-powered for the 12V-spec’ed LED module. But [Fred] says the light it produces is just the right intensity.

[Thanks Jeremy]

38 thoughts on “Pee-light Gives Guidance For Nocturnal Tinkles

  1. I just bought one of those 4″ dome lights that you can press to turn on and off from the dollar store. Put a different resistor in to dim the LEDs and it runs forever off 3 AAs. You get a nice big switch to slap when you are half asleep and it gives a nice diffused glow of light.

    1. couple it with a larger version of a joule theif and it will run much longer!

      more justification for the uc would be if the OP PWM’d the light to save energy rather than run them linearly. but really, the uc is so cheap and has much more capability regarding timing and special programming later on, pwm features, why not use it? kinda tired of this argument from the old guard.

    1. My thoughts exactly. You’d have to be pretty damn insecure if you feel like less of a man because you sit down while taking a piss. I’ve always wondered what these types of guys do when they’re taking a dump, do they stand up midway through and then sit back down again or what?

  2. Wow! I’m surprised to find my little project made it onto HaD. It’s not exactly complex as the PIR base is Olimex’s work. It is however really useful – especially as I’ve got a small baby waking me up frequently at night (and cramping my hacking time).

    I’ve had so many suggestions for improvements too!

  3. You should put either red leds or a red diffuser in that unit, it will protect your ‘night-vision’ much better. Night vision is probably the wrong term to use, it’s ‘dark-adjusted vision’ :)

  4. I know this guy wanted a project that got him into the MSP430, and credit to him for that, but a little bit of me dies each time I read about a project like this which can so easily be accomplished using discrete logic. I guess “real” electronics is probably dead, long live the uP.

  5. Am i the only person who just closes one eye before they turn the light on (and keep it closed) so it doesn’t adjust, then open it again when i turn the light off to maintain the proper vision in that eye.

  6. I agree with people who say discrete electronics would do the job. I also find it a bit irritating how everything seems to start with an Arduino and/or an Altoids tin.

    However the point of the project was to get me started with the MSP430 and get my head round low power modes, interrupts and ADC. It should use significantly less power as it spends most of its time powered down. It was a bonus that I found a use for some LED lights I had lying around that were a bit dim.

    Unlike most of my projects it’s finished and even gets wife-approval. The light is mounted neatly in the ceiling and goes OK with the mains spotlights.

  7. Am I the only one who just uses the sound of the stream hitting the water based on depth to aim? I just need a general idea where the bowl is in the first place and I’m good to go.

  8. I just can’t believe this many “guys” have this much of a problem peeing. What are you? 5 years old?
    If it’s that bad, close the door and turn on the light if you have somebody that is bothered by it.
    Man…. I mean, sheesh!

    (you should, know where it’s going by now)

  9. attaching electronics anywhere near to a direct fluid line into my bladder et all … well, that kinda worries me.
    i’m not saying i couldn’t do with a ‘pee-lite’ tho. next xmas hot gift item. bets on.

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