Milklicht - simple nightlight for new parents

A small red nightlight for late-night baby feeding that won't disturb the off-duty parent.

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This is meant to be a simple nightlight for midnight feedings. It's hoping to be easy-to-use, even if the user is mostly-asleep, and more considerate than an average flashlight to your sleeping partner.

The top puck-like shape is the light itself, which won't have a battery hanging off it - I'm going to get that in v3 (v2 is pictured). It sits on an inductive charging base and turns on as soon as it's lifted. It gets dim again when it is set back down.

The base and light are both milled out of wood I had lying around - I wish I was better at identifying kinds of wood. They're hardwood pieces from a Rockler assorment box.

The light is built around the smallest Arduino I could find that included LiPo charging circuitry. Luckily, I had a few Fios sitting around from back when I was enthusiastic about Xbee.

I modified the Fio slightly so it could know when it was charging (ie, when it was sat down on its base). I added a tiny greenwire between the "Charging" LED, ran it through a small resistor, and sent it to a digital input.

Note! Working with old Fios can be tricky because the microcontroller on the board changed several times. I ended up being able to flash mine by choosing "Arduino Pro Mini, 5V 8MHz" as the target board.

The animation when charging took a couple tries to get to a place I was at all satisfied with. I tried several methods to get a nice, even fade down to dark but was unable to avoid seeing really noticeable discrete steps most of the time. I haven't thought about it too much, but part of my smooth-birghtness-fading problem might be related to running the Neopixels off of a 3.7v LiPo rather than the specified 5v supply.

At any rate, a lone pixel orbiting slowly seems like it will be OK to live with. I'm hoping the people I'm making this for will be able to test it on their bedside soon, so I can work on other options before the baby comes. If I have time, I might work on making the pixel orbit in a consistent time interval that is useful, like 15 minutes, so it can be used as a timer.

  • Many more photos

    AKA10/31/2014 at 18:04 0 comments

    I just posted many photos of the production and prototyping process, link is here:

    I also delivered the final product (the non-silicone potted, 16-pixel one) to the new parents, who report it to be working well. (Phew!)

  • Fail / curing update

    AKA10/27/2014 at 19:57 0 comments

    So it's been about 24 hours since I poured the Smooth-On "Dragon Skin" platinum cure silicone to pot the electronics for one of the milklichts...and I have a lesson to report:

    *Don't* use gaffer tape as a mold enclosure! The silicone at the very edges of the piece appears to be fouled and will not, I fear, ever cure. This has happened to me a couple of times in the past, but I've never had the wisdom to reflect on exactly which part of the process was at fault (I'm also guilty of habitually trying to use years-old silicones, because I begrudge throwing out unused raw materials).

    I was able to rescue the piece in a pretty ugly, but usable way: I got a very sharp hobby blade and carefully cut away the outer ~2mm of each side, exposing a fully-cured area underneath.

    The downside to the silicone-potting approach (even if the edges _had_ cured properly) is that it more or less guarantees that the user will pick at it. If I had milled a mold into which I cast the silicone, I'd avoid rough/imperfect interface between silicone and wood, but that would have required a lot more time and planning and a lot less beer...

  • version 3 now curing

    AKA10/27/2014 at 02:02 0 comments

    Today I milled a third enclosure and mounted electronics inside it and made the second enclosure more ready for handoff. I am dictating this entry on mobile because my internet has been out but I just wanted to upload some more build photos (after encountering a 2mb upload limit, it seems I will have to post photos tomorrow from work)

    I potted one light in silicone, though as of the next morning the edges are still quite sticky. The silicone I used was open for several months, so there's a chance I've permanently ruined this one...

    The other light is somewhat inelegantly JB Welded in place so it sits flush with the wooden surface. I like this arrangement because, unlike the version potted in silicone, the master on/off switch is still accessible here (as are the 6 programming pins)

    I used another rare earth magnet in the light unit this time, rather than just using something ferrous (there's another magnet in the charging base). This way, you can affix the light to anything ferrous to hold it in place.

    Don't mind the weird tool marks on the edges! I was hurrying to get some prototypes to the new family, who had their baby a week ahead of the build schedule ;-)

    Here are both lights and the charger. I'll be milling another charging base sometime this week.

  • State as of mid-October

    AKA10/15/2014 at 00:06 0 comments

    Right now, I have a v2 prototype kicking around for testing with the parents-to-be.

    The v2 version is the first to have a CNC milled enclosure, so I'll be revising the CNC designs in the next round. The software is more or less done, at least until I can hear some feedback from the actual users. If you look at the repo, you can see comments (and earlier commits) that show an idea about allowing the brightness of the light to be controlled - I tested that a bit in v1 but took it out for simplicity while I test it.

    The v1 version was a gross affair molded out of shapelock. More like a Louise Bourgeois nub than a prototype. Its main purpose was to let me measure how much coaxial alignment the coils need (the answer: a lot).

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