The 3d Printers at Work

Its amazing what you can print these days. We tested out the Mendel Prusa last evening by printing this cool little light bulb sculpture.

If you could make any design in your head come to life, what would it be?

Much of what we can do these days with 3D printing is due to the hard work of Brandon.  Be sure and check out the new RepRap piece he’s making to ensure 3D printing just gets better and better: Vertical X-Axis

Be sure to check out our new “Makery Mendel” channel on Ustream, located in the links to the right.  Whenever the Makery is printing, you can see it happening.

One Month to Make: Nerf Gun Distance and Style Mod Competition

Are you a Maker?

The Omaha Maker Group is hosting a Nerf* dart gun competition for distance and visual improvement modification.

When: 7pm, November 9th

Where: The Makery

Competitors will modify a Nerf ‘N-Strike Nite Finder EX-3‘ to maximize it’s distance and/or aesthetic value.  Steampunks, artists, we look to you for inspiration.

The entrance fee for the competition is $10, but anyone can come and watch for free.

The gun may be modified in any way, provided that it remains at least somewhat identifiable as an N-Strike, and does not use pre-compressed air (such as CO2 cartridges) or chemical power. Electric power is permitted, provided the voltages are within reason (meaning the gun won’t cause a power outage).

Ammo will be standard-unmodified Nerf darts. For the contest each contestant will provide with their entry a minimum of three such darts in good condition (a new N-Strike comes with 3 darts), which will be pooled and used for the competition.

The modified weapon in ‘primed to fire’ condition must fit within a 3x7x11 inch container.

Performance for the distance competition will be measured by a maximum range test. The gun may be held by the contestant or mounted in a vice, provided the muzzle does not extend beyond the firing line. Distance will be measured from the firing line.

The cosmetic “Fine Weapon” competition will be judged by majority vote of your fellow participants.  The winner will be judged to have a very fine weapon indeed.   The winner will also gain a 10% distance bonus in that competition.

The winner of the distance competition gets bragging rights and a 1 month free membership to the Omaha Maker Group.



*’Nerf’ is descriptive of the brand of equipment to be used, and does not imply any other association with the brand.





The Mendel is Alive!

We have finally gotten the Makery Mendel to print properly!

So far we have printed a huge camera mount to connect Kevin’s camera and bike. Also, we have made a couple of new gears and linear bearing mounts to upgrade the ‘bot.

However, we are in need of funding for more plastic. The roll of PLA we are using is almost out, and a new spool will be about $65 plus shipping.

Here are some pics of stuff printed so far. 🙂

Convert old 35mm film camera lenses to work with digital SLRs

Zach sez:

This week I took a simple camera lens from a $3 film camera I got from a thrift store and attached it to a cheap Canon body cap after drilling a hole in it. The result was a bit surprising once it was attached to the camera. Since the lens gets so close to the sensor, it made an inexpensive macro lens.


Nice going!

Furnace crucible and tongs

Kevin was kind enough to bring down his nice crucible after I brought in my furnace body. The crucible is just barely small enough to fit inside the body with about 1/2″ clearance on either side.

I may try to increase this slightly, as the sides aren’t perfectly circular anyway.  I’m just not sure how to ream it out without destroying it.

So I spent an hour or so making a tool for the upcoming aluminum smelting sessions. :) I came up with a nice set of tongs that fit right around the body of the crucible. It fits nicely between the body and the sides of the furnace, but you sometimes need a bit of finagling to get it in, or out. All in all, it works pretty well.

I loaded it up with a bunch of aluminum scraps we have, as tightly packed as I could make them, and the tongs seem to hold it just fine.


Furnace at the makery

I was finally able to get my medium size furnace moved out of the shed, and into the Makery. This was used at my previous residence to melt aluminum with a waste oil burner I built from scratch. I have a feeling that it will eventually be converted to a propane, or propane/oil hybrid burner here at the space.


This is the inlet port that it cast right into the side. It takes a 1.5″ OD pipe and locks it into place with a small bolt tapped into the side.


A nice view of the inside, where there is a small plinth block to keep the crucible off the bottom, and the burner inlet with the venturi tip installed.


It has a chamber about 7.5″ Diameter and 8.5″ depth.



Ozone Generator

OMG guru Dave K continues the Robot Arms project. But first, our hero must remove offensive odors...with SCIENCE! -Travis
I've found that the fat cables that came with the robot arm I got from the Makery are out-gassing a horrid stink of damp basement. Whelwick is starting to smell like an old barn. To address this I'm going to take a two phase approach. I'll need to address the source of the odor, the cables, and also, mostly for fun, I'll build an ozone generator to eradicate the airborn odor through oxidation of whatever fumes it's been putting in the air here.

To treat the cables I intend to soak them in bleach solution for a few days. Before I do this, I want to leave the ozone generator running for a while, to see how effective it is at neutralizing the odor causing particles.

The simplest way to generate ozone, at least for me, is to use the corona discharge method to convert atmospheric oxygen, O2 to ozone, O3. I'll be using a 12kV 30mA neon sign transformer. This operates at the line frequency of 60Hz, which isn't great for ozone production, but it does work. Another way to do this is to repurpose the flyback transformer from an old CRT (I have half a dozen if anyone needs such a device). The flyback can be driven from a simple 555 or microcontroller circuit to produce a high voltage, high frequency signal which is more effective than 60Hz for ozone production. It's also smaller.

To produce the corona discharge I'm going to try using conductive plates separated by an insulator. In this case, aluminum ductwork tape and glass. First I cut a bit of glass from a piece of scrap.

I then applied the tape to both sides and trimmed it clear of the edges to avoid arcing around the edges.

The corona discharge occurs at the edges of the plate, not where they overlap, so I want as much edge as I can get. Overlap provides capacitance, which for this application, I don't need or want, so I want a plate pattern with no overlap and plenty of edge. I went with an 'E' pattern. It's easy to cut.

I decided to use copper wire from a length of Romex 10/3 as connectors, so I could easily support the panel with the connectors. To maximize the contact area I made the wire long and gave it a right angle bend to prevent it twisting.

I secured the connectors with some Gorilla Tape (it was what was handy, and it's fun to use).

The corona panel is then connected to the transformer. For testing I've attached the neon sign transformer to a variable autotransformer so that I can start out at a low voltage and ramp up the output of the neon sign transformer. Too much voltage can puncture the glass dielectric, which will shatter the glass (another reason for the tape, to contain the glass). I don't think there is much danger of this, since I'm not reaching voltages where this should be a problem, but if there are flaws in the glass it is possible.

The wiring for the neon sign transformer also has a safety gap configured. The spacing of the gap is set so that any voltage much above the 12kV the transformer secondary is designed for will cause an arc across the safety gap to protect the transformer.

To verify that it is generating ozone, and just in case it bursts, I put a container over the corona panel until I ran it up to full voltage and let it sit for a while.

The corona is fairly faint unless your eyes are dark adapted. To get visualize it I've set the camera up for long exposure in the dark. My cameras are cheapie point-n-clicks, so you'll have to put up with the not-so-great quality. here it is from both sides.

Here's what happens if you up the voltage but forget to open up the safety gap.

From the corona images it is apparent that the sharp points of the 'E' pattern are producing a lot of corona (the shape of an electric field around sharp points encourage dielectric breakdown and corona discharge, this is why bulbous, polished surfaces are so popular in high voltage labs). If you look closely though, you can see that there is discharge along the edges as well, as was intended. I don't know which is better. Regardless, it generates enough ozone. The staticy odor of ozone is strong after running for a couple of seconds of running.

I guess that qualifies this as a success.

Sous Vide: Cooking for Nerds

I’ve decided to take the plunge.

Lacking basic cooking skills for much of my bachelor life, it occurs that rather than thinking of the endeavor to procure tasty food as a time consuming chore, I should think of it as an opportunity to experiment in a chemistry lab. To that end, I’ve recently fallen in love with and purchased a Sous Vide setup.

Now, I realize its not very “Maker” of me, but I did purchase (instead of make) a very precise temperature controller, the Sous Vide Magic. For this project, the maker bit is in the cooking, not the constructing of the device. So there.

The Sous Vide Magic marries up nicely to a dumb (no fancy electronics) rice cooker, in this case a $30 10 cup Black and Decker. The temp controller allows the user to set the temperature and time, then controls the electric output to the cooker to control the temperature. A highly accurate temp sensor sits in the water bath filling the cooker.

To this bath the scientist must add a vacuum sealed plastic bag. If you’re not familiar with sous vide, this should set off alarms, but never fear: we’re cooking at low temperatures for long periods of time. The plastic won’t melt. Additionally, I’m using vacuum seal-able ziploc bags, which contain no BPA to leach into my food and turn me into a woman (BPA acts as a synthetic estrogen in the body). Bases covered.

We must vacuum seal the food (sous vide is vacuum in French, so I hear) in order to both fully expose it to the water bath on all sides, and of course, the food you wish to cook is kept in the bag so as to keep it from being soggy in the water. Simple enough.

The first experiment was a simple “Patio” steak. I cooked it at 140F for 90 minutes. The steak came out medium, tender, and quite juicy, as all its original juices remained in the plastic bag. The added benefit was a minimum of mess, as I simply threw out the bag when finished. The seasoning (simple black pepper), though minimal, seemed to be amplified. In the future, I would consider cooking for even longer, as this particular cut can be gristled and this would tenderize it more. Also, I plan to buy a creme brule’ torch so I can sear the outside of the steak briefly before serving next time. Moderate success!

Next test: Sous Vide coffee. Stay tuned.

Geiger Counter Project: Complete

As an electronic newbie, it pleases me to say that my first electronic circuit project is complete and functional.  You too can learn to solder!

In light of the recent catastrophe in Japan, I decided to construct my own geiger counter.  These kits can be purchased from Cheney Electronics.

After one afternoon of acquainting myself with basic electronic components (thanks to Brandon, Jason, and Dave for the help) and melting metal like a madman, the results:

As you can see, at sea level cosmic radiation is relatively low.  However:

At altitude, the radiation level increases significantly.  Luckily, I haven’t had readings like this while scanning objects on the ground.  In the event of encountering a radioactive agent, the clicks would actually be significantly higher than this.

Currently there is a project on Kickstarter whose goal is to set up a network of geiger counters to inform the Japanese populace about radioactivity in their country.  Check it out!