Welcome to John's Blog World...

Welcome to my little sharing space--where I come to showcase some of my custom projects and to share "how-to" info with others out there. As a lifelong "maker", design enthusiast, and design professor, this blog explains some of the little projects I occasionally throw myself into, with the intent that I may help inspire others toward self-actualization and to show them how easy it really is to construct and realize their own ideas and dreams. As Brancusi said, "Create like a god, work like a slave."

Friday, January 21, 2011

DIY Kid's Camera -- FDM Prototype "Skinning" of Recycled Technology

I think, to a certain degree, I'm a technology hoarder. I have boxes and drawers of old electronics throughout the house (and garage) that I sometimes have difficulty parting with--either for sentimental reasons (like the first mini-disc player that I decided to modify) or for practical reasons (like my micro-cassette transcriber that I may use again someday...or not). Regardless, I've got a lot of extraneous, still usable but out-dated electronics kickin' around that I'm sure my wife would love to send to a landfill (but, thankfully, hasn't). With all that "stuff" tucked away, I thought it would be nice if I could use some of it again rather than getting even more "stuff"...and maybe even give some of that "stuff" a second life, so to speak, by finding a way to maintain its usefulness. With the pervasive American attitude that everything is replaceable, we seem to be fighting against ourselves in an ironic way--working longer and harder for more new stuff, while tossing out the perfectly good stuff we already. Much of our existing stuff may work just fine to fulfill many of our needs and wants (which is why we acquired them in the first place, right) if we only had the wherewithall to either refurbish, reuse, or reappropriate it. 
Some time ago, my wife and I started noticing how enthralled our daughter was whenever we gave her the opportunity to use our digital camera. We talked about getting one of those tough, cutesy, "kid" cameras out there, but after looking at several of the commercially available kids' cameras out there, and hearing mixed reviews, I noticed that they all had about the same functionality and each had its own set of quirks. One day it occurred to me that I could probably have some fun making an even more functional kid camera based on a small digital camera that I'd purchased while on business in Japan several years ago. It was a camera that I'd actually purchased as a birthday gift for myself as I celebrated that happy day all by myself in a 2 square foot hotel room in downtown Nagoya on a drab and wet autumn day--hence the sentimental reason that I kept it around even though I'd moved on to another more capable camera long ago. This particular camera was a tiny "credit card" camera made by Casio called the Exilim EX-S1. It had a body that is much smaller than many of the kid-specific cameras out there (about the size of a deck of cards), but I figured that its small form factor would give me some design flexibility in fashioning a new camera casing around it that was more appropriately sized for a kid. Coincidentally, most of the cameras out there made just for kids are unnaturally large for children's hands and could probably do with a little down-sizing in the design, anyway. I'm not sure why so many designers seem to think that kids would prefer big, dopey-looking stuff, but there is are designers out there (probably the ones without kids) that unquestioningly follow such misguided notions. As a parent, I've noticed that kids will often gravitate to those things they see adults using all the time...even though they may still have some inborn preferences for playful shapes and show interest in those as well. Obviously, any device for a child should be able to withstand the rigors of childhood play, but that doesn't mean that it needs to look goofy. So, I figured my little design exercise to reappropriating my old camera into something that my four-year would find even more useful--both functionally and aesthetically--meant that the new design would need to be tougher, but also "cuter".
This blog entry will show how I attempted to do that using solid modeling software and rapid prototyping...and also serves as an example to my students of what can be done using engineering and design constraints out of you control. It's one thing to build something when you've got maximum control over the placement and components within a device. It's a whole other ballgame when somebody has already called the shots about the architecture of the device and you've got to work around that. Bear in mind that this was not the cheap route to take. The scale of manufacture these days is such that it's usually cheaper to buy a new electronic somethin'-or-other than to fix it up. But I ain't always about cheaper--especially if there's something intrinsically interesting about the "fix it" project that I'd be attempting.
Below is a shot of what the final, unpainted camera looks like. The ABS plastic used by our FDM (Fused Deposition Modeling) machine comes in a few different colors (white, black, blue, red, etc.), but parts created on the machine also have a rough surface that requires additional finishing steps for best aesthetics. Of course, I'll show a painting and finishing demo for FDM parts in a later blog entry.
To get started with the new camera design, I had to get creative around all the existing physical constraints of the camera I was using. This meant that I had to take into consideration both its overall shape and functional components, like the lens, screen, and buttons. After making a proportionate sketch of the camera, I used this as a template from which I could make some quick sketches of new kid-ish casing designs that were playful but still sized right for small hands (see below).
Here's a shot of the back of the camera, where a majority of the controls are located. Since nobody really uses the old-school "viewfinder" window anymore, I decided to just cover it up with the new design:
Luckily, the camera I chose has a simple rectilinear design with dimensions that were easy to measure and replicate. Interestingly enough, all the measurements I took from the camera appeared to be SAE-based units rounded to the nearest .010"...which is uncommon for Asian-built electronics, but ikely means that the casing was designed and spec'd by a state-side designer.
I also took apart the camera's charger base (which doubles as its USB interface) and took measurements of the overall circuit board's size, mounting hole locations, and all the components that needed to be designed around. To simplify things and cut down on unnecessary 3D modeling time, I usually only model up the high-profile components on a circuit board since their size usually overshadows the smaller components. If you design for the largest features, the smaller ones are usually taken care of without much more (if any) work. This isn't always the case, but it's a good rule of thumb.
I then modeled the camera and charger board up in SolidWorks so I'd have a good 3D modeled reference to work from when modeling the new case. In virtual world, this saves you lots of hassle with components not fitting correctly once the parts are finally made, although it's not completely fool-proof.
After a few hours of modeling, I completed the new casing (shown here in an exploded view with a little color added), replete with screw fastening features so the camera could still be removed, if needed, for future servicing.
I then modeled up a casing for the charger board, ensuring that there would be no fitting or interference issues between the various completed parts--one of those engineering/design tasks that SolidWorks excels at.
After saving all five of the prototype model components in an STL file format, we processed the STL files in a special program (called "Catalyst"--made specifically for our FDM machine) that generated the special CNC code necessary to build the parts on our FDM. We've got a machine from Stratasys systems that has soluble support material.  "Support material" is an expendable structure-making material used in the build of an FDM part to aid in keeping cantilevered geometry from falling over or losing its shape during construction. Here's a photo of our FDM (see below). Notice how it fits so nicely with the styling/color-schemes of both our printer and copier in its little corner space in the adjunct faculty's office. (Such strange stylistic coincidence likely stems from current design trends...unless there's one particular design dude out there with his fingers in a lot of different professional office products.)
To load the FDM machine, you just slide in a nice little injection molded plastic build platform (as seen below). This is a huge improvement over the previous low-density foam platforms that would leave gritty, sand-like urethane powder all over the office. Next, you just close the door, press the start button, and then watch the magic begin.
After a few hours, here's what can be seen through the glass door of the machine (see below). Here's how the machine works: an ABS plastic filament is fed from a spool (contained in a convenient, yet expensive, cartridge) through a heated, computer-controlled nozzle that moves over the build platform. The nozzle squeezes out the molten ABS like a precise, moving, robotic hot glue gun. It creates parts layer by layer as the build platform slowly lowers down away from the moving nozzle.
After about 35 hours of build time (due to the high-resolution we'd set the machine), I removed the completed parts from the machine by sliding out the build platform. Prototype ABS parts are usually pretty warm, like freshly baked cookies (though less tasty), because the machine heats the air in the build environment to keep the build material slightly below its solidification temperature. This helps minimize any warping issues that the final parts might exhibit from uneven cooling of the material.
A close-up shot here shows how the support material (in translucent brown--like root beer candy) allows the actual ABS parts (in white) to stand up on the build platform.
A special "cleaning station" and chemical bath is used to remove the support material. The mild acid in the bath is warmed to about 130 degrees (Fahrenheit) and eats the support away. This solution is then drained from the cleaning station once the acid loses it potency.
So, to get the all the parts rockin' clean, I put the whole build platform and parts into the cleaning station...
...and four hours later the parts were pristine! All that was needed was to rinse off the acid residue from the ABS parts with a bit of running water. (Some of the parts can't be seen in this picture because they moved around in the bath and worked their way underneath the build platform...a common occurrence that just requires a little bit of fishing around with a rubber glove to find them in the solution. We've talked about getting a nifty little stainless steel deep-fryer basket to minimize this issue.)
The final, cleaned parts look like this:
A quick test fit showed how well the original camera fit into the new case. Since the prototyping procedure isn't perfect, you occasionally need to use an X-acto blade to scrape spots here and there for better fit. It's good to note any changes that are made in the prototype, and then to change the 3D model accordingly, just in case the files are ultimately used for production.
I did a test fit with the charger board as well...
..and the final parts looked great--with good fit and all ready for final finishing and paint!
The parts can now be sanded, filled, and painted to look just like production parts...in true rapid prototyped fashion. Though I've used this process countless times for both pre-production and prototype parts, it's still fun to see a new design built from practically nothing. I don't think I'll ever get fully used to seeing a concept become a real, usable object. It's one of the reasons that I HAVE to design: building stuff is just friggin' cool.