Microscope Photography – Integrated Circuits

On Tuesday night, we were disassembling some old printers, and salvaged some large ROM chips. Patrick got the idea to use the mill to remove the top layer of the case, and expose the IC inside.  Here are some photos we took of the chip’s insides with a microscope. Magnifications range between 4x and 40x, thought the 40x were pretty difficult to illuminate properly, because the lens obscures most of the light. As for the cameras, we  used a little point and shoot and a cell phone camera, both just held up to the microscope’s eyepiece.

Easier Vacuforming with Sintra

One of the other projects enhanced by the Variac is the vacuformer.  It consists of two parts: a box with a heating element that melts plastic (background) and a perforated box which sucks the softened plastic down over a heat-resistant form (foreground).  Prior to the Variac, we’d had problems damaging the plastic sheet, because it was heated too rapidly.  Now, we can adjust the heat very precisely and results are much better.

Note: The reason for the incomplete formations in the black plastic (Sintra) is that both the objects used as forms were heavy, metal and cold; The plastic cooled too rapidly, before a good impression could be achieved.

The vacuforming equipment (both the heater box and vacuum bed) are stored in the “TOOLS” cabinet.  There are several shop vacs to be had, typically stored below one of the benches in the “less clean” area.

Acrylic Bender

The Makery’s recent acquisition of a Variac has rekindled interest in a few projects that had been on hold.  One of those projects was the Acrylic Bender that James had been working on. At it’s core, the bender is just a halogen bulb between two aluminum tubes full of circulating water. The idea is to create a line of focused heat to allow plastics to be bent accurately.  We found that it works equally well for acrylic and Sintra (Foamed PVC).  The Bender (along with the Variac) is currently stored in the “TOOLS” cabinet.

Home-made Hobbed Gears

At the Makery lately, Brandon and I [with some help] have been working on a CNC Hot-wire Foam cutter quite a bit like this one.  Ours is going to be a bit larger, capable of slicing up a 2×4 foot piece of foam (actually, the X is more like 5 feet than 4). For our Z axis, we are using a salvaged set of rails including a rack and pinion setup, but our X axis is entirely homebrew.

I’d initially lobbied for a belt setup similar to the X-axis on a Prusa Mendel, but Brandon objected on grounds of the cost for a 10 foot piece of belting.  He proposed instead using a piece of all-thread as a rack, and a curved gear as the pinion.  That was fine, but seemed like the gear would cost more than the belting. In the end, we decided to try making a gear, in the same way that extruder rollers are made for the 3d printers: Hobbing.

Tonight, I got around to trying to make the gear.  We’d settled on 3/8-16 all-thread, as it’d be sufficiently beefy as to not bend with a gear pressing against it, and to not sag under the weight of a mostly unsupported 5 foot span.  I grabbed a piece of (approximately) 1″ round aluminum from the scrap bin, and drilled a 3/16″ hole through.  I bolted the cylinder to a bearing I had lying around, and chucked it into a V-jaw in the mill vise, with one end floating free.  I chucked up a 3/8-16 tap in the spindle, and set the speed as low as it goes (I around 500rpm, I think).

From there, I aligned the tap so that the centermost full thread was parallel to the bolt through the work, so that I’d be cutting only on full threads. I used the Y-axis of the mill table to position the tap along the length of the work, and advanced the work onto the spinning tap by slowly feeding the X axis as the work turned. (The work spun freely in the bearing, powered by the tap cutting into the aluminum, like when a board lifts as a wood screw is driven.)

I initially had a bit of trouble with the work flexing in the chuck (as I was only supported from one end), but I overcame this by grabbing the outboard end of the bolt with my hand and keeping the bolt parallel to the vise jaws manually.

Overall, the process worked really well.  The tap cut nice, deep, uniform teeth into the aluminum. If I were going to do it again, I’d find a better way to hold the work (supported by both ends) in the vise; I’d also pick a better piece of material, as I didn’t bother turning the surface imperfections of out this one before I started.

Handlebar Camera Bracket

Tonight, I finally got around to finishing up the Handlebar Camera Mount project.  The mount consists of a hunk of printed PLA, sawed in half, and bolted back together around the handlebars. At the moment, I have a piece of rubber tape wrapped around the bar, under the mount, to keep it from slipping, but my Canon S5 is pretty heavy and it needs a bit more wrapping underneath.

The printed portion of the mount weighs around 60 grams, and took about 90 minutes to print on the Makery Mendel.  On the side facing the camera, you can see where we lost a bit of blue tape.  The part has an inner diameter of an inch, and is about 2″ wide, to provide good stability for the camera.

The hardware is 4 1.5″,1/4-20 stainless steel hex head cap screws. I opted for stainless because “It’s a bike, and it’s going to be outside”… The bolts were around a buck a piece, which wasn’t really any more money than the regular steel ones.  Hex-keyed is sorta like metric: It just costs more, and no one knows why.

All this puts total materials cost (including the PLA for printing) at just under $10.  The model for the printed version is available here.

 

In the Making: Player Guitar

Kevin’s been busy lately. All hail the hypnoguitar!

So far it plays 1 string and can play simple songs. The idea is to make a slide guitar that can play complex music from a program, much like “player” pianos read from sheet music. This is a demo video showing the progress so far.

Its coming together, don’t you think?

Read more on the project at the Player Guitar Wiki

Print heads for the Makery Mendel

Tonight, I was on assignment for Brandon and the Makery Mendel again, this time drilling some really really tiny holes.

These acorn nuts will be used as print heads to extrude the molten plastic on the almost-done Makery Mendel 3D printer. I started the process by holding the piece of allthread (Which has a shallow hole in the end) in the lathe chuck and threading a nut onto the end.  I know that generally a bolt thread isn’t true enough to rely on for machining, but in this case, I want the operations all true to the bolt, as that’s how it’s going to be held in use.

Next, I faced off the rounded end of the nut, being careful not to get too deep (which is what happened on the rightmost unit). I then used a tiny drill bit in the tailstock chuck to ever-so-gently drill the hole.  On the 0.3mm unit, you can see where the drill bit had a slight bend in it, and wanted to drag around the part instead of start drilling in the center.  I was able to change the orientation of the bit in the chuck to correct this.

Finally, I cut a bit of an angle on the side of the nut, making it more conical than round.  Sort of like a cut-off funnel.  Hopefully it works well. One of the nuts turned out to be plated (which, sadly, is one of the sizes I didn’t make a duplicate for)

Stepping Up…

Tonight, I did some prep work on a new EasyDriver (on breadboard) that I ordered for an upcoming project. I mounted a 4-pin Molex Floppy connector for the motor output, and pin-headers reversed for breadboard mounting.

I also milled the gear off of a scrap stepper motor and built a coupler to a fancy leadscrew I had laying around. The leadscrew in question (pictured foreground) is about 9″ long, has 5 starts (5 parallel sets of threads) and has a twist-rate of 1 inch per turn (one TPI).  The screw is further teflon-coated and uses a (probably Delrin) plastic nut.

Brandon questions if “that wimpy stepper” can drive such an aggressive leadscrew, but I don’t think it’ll be a problem.  If it does become a problem, building a new coupler (or finding a motor that has the same shaft size) shouldn’t be hard.

Printer Parts – Heater Tube

Jason notes that I forgot to post a photo of the other Mendel parts I’ve been building for the MakeryMendel.  Below are photos of a stainless steel heater tube (the one that I didn’t ruin by welding a drillbit to the inside) as well as the “order form” that Brandon sent me. His drawings aren’t anything fancy, but we seem to have gotten the job done.  For scale, the bushing in the photo is 1″ OAL, and the threaded rod heater is 1.5″ OAL.  The picture with the fire is a prototype plaster bushing that we were testing.  It’d probably work, but we dried it a bit too fast and it developed a nasty crack.

BrandonSpec (Medium) Plaster Heater

New Ring-Light

People I meet via the Omaha Maker Group often ask me what it is that I make.  I try to avoid the “Everything” answer, popularized by Jason Uher, but it seems to be sort of the truth.  Due to a renewed  interest [by people who aren't me] in things that I’m making, I’m trying to do a better job of actually driving these projects to completion, and maybe even doing a slightly better job than I otherwise might. I’m also trying to do more projects that are more “grand” in scale (for example, building a power supply, instead of a really neat custom connector; Not that either of those are really grand, in the big picture).  Below is one of these projects.

After lots of fiddling with desklamps and bounce cards every time I want to take a decent macro photo, I’d finally had it.  I started looking into buying a ring-flash accessory for my digital camera, but found them to be alternatingly pretty expensive or in the realm of “I could build that”. So I did. Read on for the details and a few more photos.

I determined early on that I didn’t want or need a flash-tube-based solution (like the one built by Patrick), which is a reflective ring illuminated by a standard photo flash.  I didn’t want to spend the money for a fancy “automatic” external flash, and didn’t want the headaches and setup associated with a cheap manual flash.

I did some initial research on running an LED illuminator on the camera’s hot-shoe trigger, but decided that it really wasn’t needed, as LEDs can just be turned on and off and don’t need to be “fired” like a xenon flash. My illuminator is powered by a simple pack of 4 AA batteries (ideally NIZN for the extra .3V).

The illuminator itself  is just 8 banks of 14 (112 total) white LEDs soldered to a piece of perf-board and a connector for power.  To make it run on 6 volts nicely (and to give me more input voltage range), I wired both halves of the LED array in parallel and then the two banks in series. I could have just put the banks themselves in parallel (and run the array on 3ish volts), but that would put my total current draw at over 800ma, which I opted to avoid.

I found a pretty neat online schematic designer, so I whipped up a schematic, in case you can’t picture what I’m saying:

From a physical standpoint, the LEDs are just soldered to the perfboard and surface-wired on the back side. I’m a bit embarrassed by my soldering job, so I won’t be posting any photos of that here.  I cut the hole in the center of the board with a few forstner bits, and finished it out with a sanding drum in a Dremel. I plan on gluing a 58mm filter ring [generously donated by Don] to the back side of the board so that it can attach to my S5′s filter adapter. I’ll probably just Velcro the battery pack to the side of the camera, as this rig is mostly for use on a tripod.

One problem I have come across is the convergence pattern on the LEDs. At distances less than about 8″, there’s a bit of a dim spot at the center of the frame. This should be correctable with some sort of diffuser and a bit of tweaking of the LEDs angle.

As for the LEDs, they were ordered from Tayda Electronics for $8 shipped ($0.04 each, plus $2 shipping). At 3.1ish volts per bank, I’m under-volting them just a bit, but they seem plenty bright.

Below is a few more pictures of the light, plus a photo of another project, demonstrating the dim spot. More photos of the device will follow, as soon as I get it into a more final form.