World's Smallest Sand Castle

Background

I was looking for some fun, clean, April Fools pranks when I found a printable joke about the worlds smallest sand castle, "carefully crafted by microscopic nanobots." What you really do is glue a tiny pinch of sand to the paper.

This might fool some gullible, elementary aged children, but in my line of work we can easily view objects on the micro and nanoscale. We have powerful optical microscopes, scanning electron microscopes, confocal microscopes, laser interferometry, etc. So I got thinking about what it would take to really build the world's smallest sand castle.

The Idea

I think it would be a fun project to actually build the world's smallest sand castle (if it hasn't been done already). To accomplish this I would build it from real grains of sand by stacking them one at a time like giant building blocks. Okay, they are actually tiny building blocks, but think about buildings that are made from huge granite blocks. I would treat each small grain as if it were a huge building block. That gives you a sense of scale of what I want to build.

There are many different types of sand, but the typical size distribution goes from 0.06mm to 2.0mm. To make building easier I would try to find a high purity silica sand with grains filtered towards the smaller end of the spectrum, around 0.10mm. I think the biggest problem with building on this small scale is that the building blocks won't be square. Unlike salt crystals, silica crystals take a much more random form and will be rounded on all sides. This means I'll need to be creative to get the grains to stick together. The most obvious answer would be to glue them in place.

The last, and I think most difficult / expensive, challenge to overcome is how to actually perform the building.  How do you move the sand grains into place and glue them there?! Really steady hands and lots of patience? I think not. I've done lots of work lately playing with servos, and motor controllers, but those just don't have micro-scale accuracy. After a little research I think I'll use micromanipulators. These are mechanical devices used mostly by biologists to work with individual cells under a microscope. If I can get my hands on one or two of these things then I might have a shot at a world record.

Progress

02/03/2015 -

Has it Been Done Before?

Using my Google-fu I checked for any prior attempts at my idea. The current claim to the world's smallest sand castle comes from Vik Muniz. He has taken an individual grain of sand and used a laser to etch a picture of a castle. I think this is awesome, and a clever twist on the idea of a sand castle. However, it does not qualify as a 3D structure build from multiple grains of sand.

I also found a few photos of small castles built with more traditional techniques by J.W. Gruber. He makes a tightly packed block of sand then carves out the castle. Probably the smallest freestanding examples with extensive detail.

Here is a gentleman who does micro-sculpting by hand between his heart beats. He could probably do it without using any extra equipment. His pace is a little slow, but that's exactly the attribute that makes him successful: Willard Wigan TED Talk

Looking For a Micromanipulator

• New on Amazon: $1,500
• Used Industrial: $150 - $500
• 3D Printed Low Res: $100

The 3D printed version actually gives me an affordable way to research the feasibility of this idea. As soon as I get the nozzle on my printer repaired I may dig into this.

03/31/2019 - I still want to do this one. It just seems unique and fun. I've had the 3D-printed micromanipulator and VR goggles on my desk for at least a year.

I've been stuck on the optics. I'm trying to maximize both the free working distance and the depth of focus around the optimal magnification level for medium sand grains (about 0.1 mm). If you've ever used a microscope, you may have noticed that everything looks flat or out of focus. This is because when you zoom in to high magnifications, only a thin section of material is in focus.

With my design, I've been trying to overcome this flatness and give a sense of depth and dimension by using stereo 3D microscopy. This has been done successfully by Gary Greenberg, but he looks like an academic gone commercial. I can't afford his equipment, and he doesn't publish the design since he's selling them for over $40,000 on Amazon. From his websites it looks like he's relying on Z-stacking to get full-depth 3D images. In other words, the camera automatically takes images at different focal depths, then a computer combines all the parts that are in-focus to create a neat looking picture. So it's not REALLY real-time, live 3D viewing.

That depth of focus is going to really make this project a challenge. My problem is that I don't have the money to just play around with expensive optics, and I don't know enough optics theory to design my system on paper to know exactly what to buy and how that translates to a workable system. I've gotten a rough idea by studying scopes for soldering electronic components, and I found DIY stereo microscope that I might try.

Or maybe I should build the end-effector first and try to find a lab with a standard stereomicroscope and see if a standard mag like 65 or 90 is sufficient for what I need. Then I'd feel okay dropping the $250-$2500 for a standard lab unit.

Avatar / Mini Me App

Background

During my Master's studies in Electrical Engineering I took some programming courses. One course that I enjoyed was called, "Visual Interfaces to Computers." It was about the many ways that computers can obtain and use visual data from the real world. Since that time I have had several ideas on novel ways to use visual data.

In a completely unrelated line of thought I often think about pictures that people use to represent themselves in chat windows, gaming icons, Facebook, forums, and the many other virtual worlds. These little self-representations are called avatars. I always have a hard time figuring out what picture to use. I don't like pictures of myself, but I can never think of any one thing I like SO MUCH that I would use that as my avatar.

The Idea

Create a cell phone app (I guess there could be PC / MAC and online options as well) that will take a front and side image of you and create a virtual likeness of yourself. To be clear, this is not a 3D scanning app. This would be something much more rudimentary. The app would identify the location and shape of head, body, arms and legs. It would create a cartoonish figure by matching the shapes from the picture against a database of common shapes. Then it would analyze the head in more detail to get shape and color information on the hair, ears, eyes, nose, mouth, etc. and match those features against the database of features to find matches. The output would be a cartoon, 3D likeness of yourself that could be dressed up, altered, colored, etc. You could rotate and zoom the model and save pictures that could be used as avatars.

The part that makes this idea novel from existing versions is that it creates the avatar based off real-life images.

Progress

12/02/2014 - Some similar ideas already exist, but not in exactly the way I envision.

• Yahoo used to have an avatar generator that was very limited but is no longer supported.
• Nintendo Mii Characters were introduced on the Wii.
• Second Life has the most detailed avatars.
• Awesome 2.5D face from photo at Site Pal.
• Other sites

But I haven't found anything that makes a full 3D avatar from from pictures.

Water Jouncers

Background

I really have no idea why I thought of this. The kids woke me up early and I couldn't fall back to sleep. While laying in bed this morning I got a bunch of ideas. My brain is a single-thread processor. It's like a railroad track but there are a million switches. I think along one thread, sometimes detouring on tangents, evaluating ideas more deeply or completely switching directions on a new but related thought. I often backtrack and take different switches that I marked as interesting along the way. Conversations are like this. Jenn and I sometimes find it fun to trace conversations backwards and see all the different switch points.

Anyways, I'm sure there was some half-logical track that got me onto running across the water.

The Idea

A stilt contraption that displaces water allowing you to run across a water surface. First solve the mechanics of water displacement and find workable human input scenarios. One possible answer is to displace lager surface area like a lizard. Problem is with retraction speed. Evaluate an artificial webbed foot that expands on contract, putting force into springs. Then upon contraction the springs pull the webbing in and propel the foot out of the hole of displaced water. Or maybe the actual foot never enters the hole. Maybe it's only the mechanical device goes into the pocket, and the springs pull it out again, reset by the force of every step.

Progress

11/27/2014

Lizard that can run on water

Robot that can run on water

Just for Fun:

Fake but Fun

Jeff's Miracle Boots

No-Boat Water Skis

Background

The Aquaskipper has proven that human power can propel a person above the water using hydro foils. People have attempted self-propelled water skis in the past, but the designs were all horrible. The Mythbusters' Adam Savage tried a typical approach of floating pontoons with flaps for propulsion. They turned out to be unstable and not mobile. What we need a good, functional design.

The Idea

I need to sit down and determine the physics required to keep a person on top of the water using a combination of buoyancy and propulsion. Then I need to explore the design space around these two factors and design water skis that operate similar to the principals used in the Aquaskipper. In my mind I envision something like cross-country skis for water. Cross-water skis?

Progress

11/27/2014:

A Purely Buoyant Solution - Archimedes' Principle

Put simply, the buoyant force on a submerged object is equal to the weight of displaced water. For a purely buoyant design this means displacing enough water to hold up a person. Assuming a weight of 80 kg (roughly the average American male) at standard temperature and pressure, this means displacing approximately 80 liters of water. Sounds like a large volume, but that equates to two skis that are 25 cm wide, 10 cm deep and 160 cm long. So I guess Adam Savage had it about right with his big dorky skis (for the record I was rooting FOR him).

In my opinion this is the worst way to design these skis. This is the maximum footprint of a workable design, so we should be able to stay well below that size by requiring the person to move to stay afloat. More like the Auqaskipper which uses little buoyant force.

A Purely Dynamic Solution - Barefoot Skiing

A rule of thumb for barefoot skiing speeds says take your weight in pounds, divide by two and add 20 miles per hour. This gives around 37.5 mph or 60 kph. That's really fast. The Aquaskipper obviously goes much slower than that. I found a paper on water skiing biomechanics that showed a chart of rope load that was half the skier's weight while going 15 kph.

Arduino Decibel Alarm for Noisy Kids

Background

My wife and I are night-owls but our children are early risers. We used to get up with them every morning, but have slowly trained them to do their morning routine by themselves. The only problem with this arrangement is when the kids decide to reenact "Lord of the Flies." They can get very noisy, interrupting my precious sleep. I get really cranky when I haven't had enough sleep. The kids are very responsive when I tell them to be quiet, but they quickly return to their activities and resume their loud volumes before I can drift back to happy land.

If my wife or me sits down with the kids and constantly reminds them to be quiet, then they do pretty well. But then only one of us gets to sleep (usually me). I just wish there was some kind of electronic babysitter that could tend the to the kids' volume during that hour between six and seven in the morning.

The Idea

Use an electret microphone on an Arduino to listen to the kids as they play. When their noise level goes too high then it will trigger a recorded message that will encourage the kids to be quiet.

This could be used in multiple ways. If noise a single, short noise spike is detected (like a shriek) then it could play a nice recording of Dad saying, "Remember to be quiet kiddies." If the volume is steadily rising it could say, "Hey, your getting out of control, time to do something more quiet like reading a book." Finally, if the volume stays steadily loud it could play something truly frightening.

Progress

11/27/2014 - I've got an Arduino, and an SD card kit that can be used to play MP3 files. I just need to find a suitable speaker and microphone. Instead of a speaker I've got an FM transmitter that can be connected to the Arduino and I could turn on the radio to a blank channel. I think a speaker would be easier, and more portable.

Hardware Device to Make a DVD Player Act Like a Hard Drive

Background

I'm always in the pursuit to maximize the utility and convenience of my Home Theater PC (HTPC). For me this means finding a balance between cost, performance, footprint and versatility. I want to be able to play DVDs, watch Netflix, YouTube and possibly even some light gaming. This is all available on a Windows platform, but that comes with the cost of a Windows license and the hardware to keep up with Windows bloat. I've tried Linux, but it just doesn't support Netflix reliably. Android has everything except DVD support. There are some new Android mini PCs that would work great if I could just find a compatible DVD player.

While searching for DVD drives I found other people who want to access DVDs on other devices. It seems that hard drives will work on EVERYTHING...TVs, phones, tablets, computers, etc. Why can't DVDs have the same support?!

The Idea

We could solve everyone's DVD problems by creating a hardware device sits between the DVD player and the computer / TV / android device. The device would read the DVD player but make it look like a hard drive to the computer.

I know that this device is 100% possible. In the worst case scenario the device is a mini computer that plays the DVD and transcodes it into an MPEG file. I guess basically a hardware transcoder. That's not cost effective. To be cost effective it would have to operate on a very low level, reading the DVD to see what options are available, then present them as a limited set of files on a hard drive, each file name representing a different set of movie options.

I think the biggest hurdle is solving the problem at the file transfer level. You have to present files that are readable by the computer, which for really stupid devices means video and audio files. Dumb devices only know how to read different file formats, so how do you convert the request for a byte stream into a DVD read? It may not be possible to get that low. Maybe transcoding is the closest you can get.

Progress

 11/27/14 -I really don't have the background to research this device right now, and I'm not interested in learning that low level programming, so this idea is gonna sit on the shelf, probably forever.

Automated Home Library

The Idea

Tonight Jenn and I were talking about what we should do with the spare bedroom. We just moved our two-year-old out of the crib and into a twin, sharing a room with her older sister. We could buy another bed and turn it back into a guest bedroom. We could turn it into extra storage space, or expand our office and scrap-booking space. I've always liked the idea of a library or reading room where the kids could sit and read. But it's only the idea that's nice. In practice the kids pull all the books off the shelves and onto the floor. So talked about different ways to store the books or limit access to keep things somewhat controlled so we can avoid the hassle of getting them to clean-up everyday. I mean, if there's something we DON'T need it's another room to clean.

I'm a process engineer with training in lean manufacturing. I spend a great deal of time at work cleaning up messes, self-induced or otherwise. To avoid future methods we use a method called poka-yoke, which is Japanese for mistake-proofing (literally yokeru=avoid poka="inadvertent error").

So we thought, maybe we keep the books in boxes, but label the boxes so we can easily find the books. Then we can control access and avoid the mess. But the problem becomes awareness. We forget which books we have, and if the kids can't see them, then the kids won't ask to read them. We could catalog the books and have a list. Even better if there were pictures too. Maybe in a computer so it could be easily searched or sorted. Yeah, now we're literally building a library.

So I thought, how cool would it literally build a library. I don't want to staff it...maybe I could have a robot do all the work. Let's take the room and turn it into a Redbox-style machine with a computer interface. The books would all be stored in custom shelving - horizontal slots with barcodes. The kids could pick a book from the catalog and the robot would go get the book and send it through a slot in the door. The robot would run on a track and get instructions from the computer on where to get and store each book. Then I could limit access to two books per child. They gotta return a book before they can get any more. Redbox style...just put it in the slot and the computer / robot puts it away.

Progress

I really like this idea, but I don't want to totally dedicate that room. It would be a cool "look what I can do" project, but I don't know that I'll ever pull the trigger. Sometimes it's just fun to know that I could actually do that.

3D Texture Generator

The Idea

When I took a computer graphics course as part of my master's degree I learned about using textures and skins to make objects more life-like. In one lecture we touched briefly on the idea of 3D textures which can be applied to voxels in a volume or in slices to surfaces. From there I realized there could be value in creating realistic 3D textures to be used in a variety of contexts.

The world is naturally perceived in three dimension. Instead of trying to draw a realistic looking 2D picture you could instead create a realistic 3D volume and slice out whatever surface you need to display. The main advantage of this method is the ability to parametrically generate 3D volumes using actual material properties. The visual properties are essential - color, reflectivity, scattering - but even mechanical, electrical and chemical properties could be used to generate aggregate materials. For example, you could create a realistic 3D concrete texture using the properties of cement, gravel, sand, etc. A program could accept inputs for material types and mix ratios, calculate the resulting structure, and apply the resulting visuals to the structure.

By compiling a large number of such calculators you could create a software package (web-based?) that can create 3D textures for many different materials. It could be a handy tools in the belt of computer graphics programmers. It might save them alot of work, and give them a way to easily add variety to their projects. Textures could be randomly generated each time and cut down on the amount of repetition in games, movies, etc.

Progress

I'm not actively pursuing this idea right now. I'm not a full-fledged programmer, and one of my pet-peeves is bad software written by someone totally disconnected from the end-user. If my career ever moves towards the gaming industry then I will come back to revisit this.

Whiteboard Alternative

The Idea

I work in the semiconductor industry, and nearly everyone has a whiteboard in their cubicle to assist the many discussion we have about equipment, processes, statistics, etc. Whiteboards are a cheap, effective, and relatively clean alternative to projectors, blackboards, etc. But they still require consumables, and they're not totally clean.

For a while I've been wanting to see if I could develop a better alternative. It would be nice if I could improve cost and invent something manufacturable and marketable, but at the very least it would be fun to have something unique for me to use.

Progress

Giant "Magna Doodle"

This would be a 3'x4' Magna Doodle board. Magna Doodles use an opaque ferrofluid trapped inside small cells. When a magnet is touched to the surface, the iron particles in the fluid come to the surface creating dark spots / pixels.

Pros:

• No mess
• No consumables
• Variety of cheap magnets

Cons:

• Poor resolution
• Monochrome
• Wears out with use
• Expensive to piece together or custom build one large sheet
• Hard to erase just one small section

Magnetic Viewing Film

 Viewing film operates on a similar principle as the magnadoodle, but the fluid cells are much smaller, and typically green. I've never played with it in person, I should buy a sample to see how well it would work.

Pros:

• No mess
• No consumables
• High Resolution
• Variety of cheap magnets

Cons:

• Monochrome
• Slow response?
• Have to piece multiple sheets
• Hard to erase just one small section?
• Fragile 

8/9/2014 - I got my viewing film last week, just a small sample. It's really fun to play with, but the difficulties in using it for drawing became quite clear. The film is plenty responsive; it's too responsive. It can produce decent contrast, but when you pull a permanent magnet away the contrast changes as the fields move through the film. Wherever you start and stop a line will look blurry. You'd have to use an electromagnet that activates when you touch the surface. That's doable, but more hassle. The last drawback is with erasing. You have to hit the entire board with a uniform field from the backside. That's just a little too much bulk and complexity for me to mess with right now. 

E-Ink

 E-Ink is a new technology used in some e-readers. Instead of using a ferrofluid, electronic ink puts a dark ink/oil inside the microcavities along with charged, white particles. The microcavities are coated top and bottom with a conductive film. Applying a charge to the film can move the white balls to the top or the bottom to provide pixels and contrast.

Pros:

• High resolution
• Long life
• Robust housing
• Multiple colors possible.

Cons:

• Requires electricity (could use manual generation)
• Micro-fabrication is expensive and difficult

This is my favorite method. I would like to learn how they manufacture these displays so I could make one of my own. I emailed the company to see if they would sell me a batch of ink that I could put on my own surface. Of course I got no response.

Giant BoogieBoard

The BoogieBoard is an LCD display that does not require power to retain an image. It uses chiral liquid crystals to form a cholesteric, bi-stable display. The crystals are oriented in parallel planes which align in a cork-screw fashion. Within each plane the crystals lie flat, aligned uni-directionally. This crystal medium will selectively reflect light depending on crystal orientation. I found the actual manufacturing process in a whitepaper written by Kent Displays. I have enough information on this idea to actually try building a device.

Micro Magnet Array

Giant grid of magnets with poles all in the same orientation. Pull forward or push back. Same principle as magna doodle only with magnets instead of iron. Magnest would have to be small enough and far enough apart to reduce their influence on each other, and that will limit resolution.

Dirt Drawing / Sand Writing

Writing in dirt may be the oldest form of written communication. For this project I'd use sand. I'm sure there are several ways this concept could be realized. You could have a tray of sand and use it like they do in the high contrast, flat sand art. Or you could have a packed surface using etched lines. I would need to think of a good way to make a vertical unit. It would be heavy.

Generalizing the Principles

Okay, now that I've gone through a few different ideas I think I can start distilling the underlying principles by which these devices operate. Basically you are creating contrast between a background medium by adding or moving another material. The forces being applied are electric, electrostatic, magnetic, and direct physical contact. If the background medium is liquid, and the secondary material can diffuse in the medium then the secondary material must be physically isolated to keep it evenly dispersed. If the secondary material can freely move, then you must deal with a mess or have a recycling method.

Types of Forces:

• Applied
• Direct
• Pneumatic
• Hydrolic
• Friction
• Spring
• Gravity
• Electromagnetic
• Electrostatic
• Magnetism
• Nuclear

Life Tracker

Background

I've always liked the idea of keeping a journal, but I wish it could be easier. Putting my thoughts and feelings on paper not only makes them more real to me, but also gives me a chance to reflect on what happened and make decisions for the day to follow. My problem, as I've mentioned before, is that I hate writing. I have a difficult time coming up with the adjectives that accurately describe what I'm feeling and thinking. The time it takes to actually write the words down feels like wasted time, and I don't really enjoy the physical process of writing, I rather abhor it. Finally, even when I get started on a journal, I have a really hard time remembering to stick with it night after night. I think most of my ideas come from my laziness.

 

 The Idea

What if there were a way that I could have a journal without having to sit down and write everything out, and without having to remember to do it every single night? Maybe I could set an alarm that goes off every night to remind me to write? And as long as I'm going to use technology, why don't I type my journal instead? In fact, why don't I just have the computer send me an email that asks me stuff every night, and all I have to do is answer the questions? And what if I could customize the questions? I could track personal goals, feelings, health, wellness, physical fitness, relationships, pretty much anything important that I might want to track on a regular basis. A web form could be used to simplify the entries as much as possible, then spit out an entry using "normal language" (computer-generated).

Now I've got all this data that could easily live in a database. I might as well do something useful with it and apply some statistics to try and find correlations. Does my mood shift seasonally? Is my blood-sugar or well-being affected by my diet? Do I really struggle with meeting my physical fitness goals based on the temperature outside? By drawing correlations the computer can flag me of associations that I should look into. Knowing yourself is one step to improving yourself.

It should all be part of a website with associated mobile apps. You get to choose everything. Notification method (email or app), times, types of questions to fill out. There would have to be a big list of options, and efficient way to present them (maybe a dichotomy). It would be subscription based, and there would be a separate section for analytics.

And of course there must be a script that recommends other adjectives based on the ones you type.

 

Progress

 12/12/2014 - Sometime last year I actually sat down and created a USB drive with a mobile server and WordPress installed. I spent a week trying to figure out the backside of WordPress and decided I hated the whole thing. If I'm going to build a site myself then I'll probably need to write it from scratch. My questions is whether I should invest the time to learn PHP or just stick with ColdFusion. There is probably better front-end support for PHP, but that's a time investment.

I wiped the USB drive and will start fresh with PHP and MySQL. Maybe I should pay someone to help me get started?

Sound Test Website

Background

Back when I was reviewing computer hardware for BenchmarkReviews.com I had the opportunity to learn about audio equipment, performance and files. I only wrote one article that dealt with surround sound, but I quickly learned that it's a format for which there is not a wealth of resources on the internet. At the time I really wanted an objective way to compare the quality of different surround sound formats. I happened across audiocheck.net, a website run by Stephane Pigeon that provides exactly what I wanted, only for stereo sound. I talked to Stephane about adding support for surround sound, but he had a different vision for his site.

The Idea

 What I would like to do is create a website much like his that includes audio files that can be used to test surround sound systems to make sure they are working correctly. I also want a blind test section that plays different audio clips that transitions sounds from one channel to the next (like footsteps, or a driving car or something) and have the user take a test to see if they can correctly identify the motion of the sound. This would provide one objective method to rate different pieces of hardware and different suround sound technologies.

Progress

07/07/2014 - Part of the problem when I first envision such a site was poor audio support by the browsers. Everything had to be performed via download and client-side software. With HTML5 and updated browsers I think this is now a real possibility.

09/13/2015 - It took me a year, but I finally decided on a language to learn. I'm taking the Full Stack Web Developer Nanodegree from Udacity. When I'm done I'll make this page in Python as part of my beginning portfolio...eventually.

Fashion Consultant App

Okay, so I am fashion impaired. I have a terrible time picking out what to wear just from the limited wardrobe I already own, and an even worse time trying to select new clothes. I don't really want to do all the reading required to teach myself how to dress so as to not be an eyesore. Socks and sandals? Who CARES?

Tonight Jenn is asking about what clothes I need. She showed me some shorts and asked which ones looked nice. "I don't even know where to start."

Then it hit me. I need an app to help me dress, and to help me pick out new clothes. At the very basic level I need to be able to input my wardrobe and have the app tell me good combinations for outfits, tell me what I'm missing to make some good combos, and give me advice on what to buy. It needs to integrate with the camera so I can take pictures of the articles of clothing (of course there needs to be a simple camera color calibration). Clothing recognition would be nice, but I've done some coding work on that and it's pretty tough.

Then next time Jenn asks me what I think about a pair of shorts I can just take a picture and have my expert consultant tell me how it fits into my wardrobe.

Maybe you could take it to the next level and take a picture of yourself and have it recommend styles of clothing for you.

Could you really distill a fashion consultant into an app? Maybe not high fashion, but to get an engineer dressed appropriately I think some fashion basics knowledge would be quite feasible.

TV Screen Protector

I did this project years ago. It's a cheap way to protect your big-screen TV from flying objects (toys specifically). I just recently got the motivation to start sharing past projects, so I wrote an Instructable.
TV-Screen-Protector via Instructables

Update 7/9/14: Yay! I guess they liked my project enough to feature it on the homepage! It's kind of addicting to get positive feedback. Now I'm wondering what else I can make and publish.

Non-Insulating Weight Blanket

The Idea

When I sleep I like to have a medium to heavy weight blanket on me. I'm also a little quirky because I also need to cover as much skin as possible, so I typically sleep with socks, long pants and long sleeves. On warm nights I obviously get too hot with all that insulation, so I have to toss the blanket and/or the clothes. This makes it more difficult for me to get a good night's sleep. I'm sure I could learn to live without all my securities, but I like to increase my quality of life when it's convenient. Some people grew up in more difficult circumstances where such securities are practically a necessity. These types of dependencies are commonly tied to autism and Down's syndrome. I identify with people on the spectrum and often suspect and joke that I, myself, am on the spectrum. I've remember one parent's story about how their high needs child would come home at the end of the school day and burrow into a pile of blankets to recover from the unpredictable social jungle that is called Junior High. So I've thought to myself, "Wouldn't it be nice to have the security without the added discomfort?" That's how I came up with my idea of the non-insulating weight blanket. It's a blanket of equivalent weight without the insulating properties. I want one of these blankets, but I can't find one sold anywhere, so I'm going to have to develop it myself.

 Progress

 My favorite blanket right now is a denim blanket made by my wife. It's about the perfect density and provides a secure level of pressure, but it probably falls on the lighter side of a good security blanket. It's 56 inches wide, 70 inches tall, and weighs 4.8 pounds. That's a pressure of 0.0012 psi (or 2.5 feet of air, 0.9 kg/m^3, 84 microbar, 8 pascal, etc.). I found some blankets made for people with sensory processing disorder. A blanket of similar size can be up to 25 pounds, but I think those are designed for temporary therapeutic relief and not meant to be used for an entire night. In any case it seems the acceptable range of pressure is fairly large.

Critical Ratio

My first inclination in such a design is to modify the thickness to possibly exploit the critical insulation ratio. When you insulate a round object the added insulation slows down conduction but speeds up convection. There is a critical insulation thickness such that when your insulation is below the thickness you speed up heat transfer by adding insulation. And when your insulation thickness is above critical adding insulation slows down heat transfer. So my first thought is to estimate the critical ratio for a blanket around a person.

Without going through a bunch of explanation (here's a good link for that) the critical ratio basically comes down to the rate of conduction vs the rate of convection, or k/h. I estimate the thermal conductivity (k) of a denim blanket to be around 0.04 W/m*K. Estimating the convection coefficient (h) is a little harder, but to just get in the very rough ball park let's think about a human body. The internal temp is 37 degrees C, and the room temp is 20C giving a delta of 17C (or Kelvins if you wanna be technical). Using a guess of 2 square meters of surface area, 80 Watts heat generation that gives around 2 W/m^2*K.

So that gives a critical radius of (0.04 W/m*K)/(2 W/m^2*K) = 2cm. So, um, you might be able to cool down a finger...but your whole body ain't gonna fit inside 2 centimeters.

Mesh and Material

If I can't win by changing the thickness of the blanket then I will have to remove some of the insulating material and turn the blanket into more of a mesh. That will cause a hit in density, so I'll have to modify the material composition to increase density. The ideal material would be thermally conductive, easy to wash, easy to sew or press, flexible and cheap.

Material	rho (gm/cm^3)	k (W/m*K)	Washable	Sew/Press	Flexible	Cost ($/lb)
Dirt / Earth
Polypropylene

Micro 3D Printer

While researching different 3D printers I found they all use stepper motors for positional control. It got me thinking what other technologies exist that could be used as replacements to improve cost, accuracy, etc. In my industry we use interferometers for nanometer-scale positioning. I wonder how this could be applied to 3D printing. I doubt it will be as cost effective as stepper motors, but it certainly will improve accuracy. Then I got wondering how small you could make a 3D printer. I haven't seen anyone compete for printing the smallest object yet. Well, if you count a FIB as a 3D printer then this doesn't really matter, but I'm still thinking objects observable with the human eye. It might be a fun way to show what the technology is capable of doing and possibly open up some new markets or applications. So for positioning control you could use simple, amateur interferometers. Maybe modify the kind used for amateur astronomy. There are other positioning technologies that might be better suited. This may also require a change in the actuators for improved accuracy.