Engineer & Entertain

Ideas I grapple with

Archive for the category “Geek”

Vonnegut Was Right!

Research from the Computational Story Lab at University of Vermont found there are six main plots in story telling.

  • Fall-rise-fall
  • Rise and then a fall
  • Fall and then a rise
  • Steady fall
  • Steady rise
  • Rise-fall-rise

I am glad to see we finally have research to confirm Kurt Vonnegut’s hypothesis decades later.

Spiraling into control

I am building a table for my Handibot as one of my biggest challenges thus far is registering the machine in the same spot when I move it to change bits. The table will have dog holes bored every 3 inches. The Handibot will have a fence and work pieces will be clamped against the fence via offset clamps.

The screw does not go through the center of the circle. It is offset so the circle rotates like a cam.

Rather than cut circles and mount them offset, I decide to make cams based on the Fibonacci spiral. I am not sure if there is any advantage or disadvantage to this. My reasoning was that a spiral would have a smoother transition in clamping. We’ll see how this works in practice.

I laid out a rectangle and spiral based on the Fibonacci numbers with a pair of dividers. Alternatives to using dividers/compass include:

  1. Multiplication – the 3″x3″ square is effectively the number 8 square in the picture below. To make the 5 square, multiply 3 by 5/8ths. The 5 square is 1.875″ x 1.875″. To make the 3 square multiply 3″ by 3/8ths and you will find the 3 square is 1.125″ x 1.125″
  2. Print a spiral. Adhere the paper to your work piece with spray adhesive and cut it out.

I laid out a 3″ x 3″ square on a scrap of 3/4″ thick plywood. I set my dividers to divide the square into 8ths.

The 3″x3″ square can effectively be thought of as the 8 square

From the outer corner of the 3″ x 3″ square I paced out five spaces. This is the corner for my 5 square.

Five little steps and I made the 5 square

I repeated this process to create the 3 square, 2 square, and 1 squares.

I used a compass with a pencil to trace the arc in each square. The compass legs are spaced the length of a side of a square.

Then I cut out a small rectangle from the 8 square. This provides a handle for me to grip when tightening the clamp.

Cut with a handsaw.

Next I used my fret saw to cut the spiral. I used a sander to sand down to the line.

Golden

I drilled a 3/4″ diameter hole in the spiral for a dowel. The dowel is 1.5″ long and glued in place.

Looks like a duck

The clamp does hold pieces against a fence, but I am unsure if it will be strong enough while using a CNC router. I’ll report back with those results eventually.

Band names of 2015

Is your resolution to learn to play guitar, form a band, rise to fame, do coke off a hooker’s ass, trash a hotel room, fall from fame, and make a comeback? If so, here are the band names I came up with in 2015. If you use one of these names, please remember me in your Grammy acceptance speech.

  • Midnight Hawk Snack
  • Tiger Blender
  • Most of a Pizza
  • Raw Floor Biscuit
  • Cock Orphan
  • Break the hymen
  • Bring a change of underwear
  • CLITHERO
  • Two guys, a girl, and a pizza place

Science Friction

After watching “The Hot Seat Card Magic Trick” episode of Scam School I became interested in the Pilot Frixion pen. Watch the video below if you want to learn the trick in full, but what interests me is that the pen’s ink is erased by heat.

Previously I was only aware of the erasable pens which used an ink mixed with a rubber cement like material. Until the rubber cement set, the ink was erasable.

My first thought, “Could I use this pen to journal my plans of taking over the world and then throw it in a hot place to erase the evidence when the FBI raids me?”

The answer is yes, but really no. While the ink does disappear with heat from an open flame, oven, or vigorous rubbing, the content is still easily read by applying a raking light to view the impressions made by the pen.  Not to mention the FBI could use electrostatic detection to read my plans for global domination.

A raking light is applied so the impressions can be read.

Highlighting some of the impressions.

 

Furthermore, the ink reappears when the paper is chilled in a freezer. It is not as dark as when it was first written, but it is very legible. I like the idea of writing a secret message, erasing it with heat, writing a non-secret message over it, and then having the recipient freeze the letter to read the hidden message.

The original message

The message reappears after being frozen for less than a minute.

 

Microwaving the ink would require a considerable amount of time to be erased. I microwaved an index card with a message for 10 seconds, 20 seconds, 30 seconds, 60 seconds, and 120 seconds. When microwaving the card, I also microwaved 1 cup (250 mL) of water. The water was there for safety reasons as I was unsure if the index card would catch fire if it was microwaved alone. The message remained intact until it was microwaved for 120 seconds. After being microwaved for a two minute duration, small portions of the message were erased. Not enough for me to recommend microwaving the message as a method of erasing it for a magic trick or removing evidence of a plan for global domination.

After microwaving for 120 seconds

After microwaving for 120 seconds.

 

The Frixion pen is useful for magicians, people who schedule their calendars with ink, and students who want to appear they live life on the edge by taking a math test in ink. Despite all of these uses I cannot recommend it for planning the crime of the century.

I CNC what you did there

I make it a point to not purchase a new tool or material unless it is truly needed. The basis for this rule:

  • I do not want to buy a tool that I will not use frequently enough to justify its cost.
  • Often I can use a tool I already have or build a jig to allow the necessary process to occur.
  • Having a limited set of tools puts constraints on my work and constraint breeds creativity.

Recently though I made a purchase which violates this very rule.

I have no need for a robot which can perform routing, engraving, cutting, and milling operations. But I have wanted one since I used a computer numerical controlled mill in my high school engineering class. Creating with a CNC machine provides an abundance of possibilities. The Handibot has an astronomical amount of potential.

My main attraction to the Handibot was twofold. First, I did not have to assemble it. There are many plans and DIY kits to assemble your own CNC for far less than purchasing a ready-made machine. Knowing that accuracy would be paramount in a DIY kit I opted to not go that route. I know others have built their CNC machines accurately and easily, but I do not have the patience to do so.

My second draw to the Handibot was its size. CNC mills range in size from small enough to fit on your desk to large enough to handle a 4 feet by 8 feet sheet of plywood. You bring the machine to the workpiece with a Handibot. While its cutting area is 6 x 8 inches I can move the Handibot anywhere on the workpiece and run a process. I am not sure how often I will mill on a sheet of plywood, but it is nice having the ability without having to dedicate the space to a large machine.

Setup

The software installation was fairly straightforward; I followed the dialog boxes as directed. I did have a run time error when I tried to run ShopBot 3 because it tried to divide by zero. Turns out I was supposed to run ShopBot_PRSDesktop2418.

It comes with VCarve Pro which is the design and layout software. PartWorks 3D is CAM software. These two bits of software can either be downloaded and installed from a zip file or with the included flash drive. The flash drive also has ShopBot Design (communicates between the device and computer) and ShopBot Editor (reads and edits the ShopBot files).

Use

After installing the software, I zeroed the XYZ axes as directed. I then ran Shopbot’s version of “Hello World”.

The Handibot carves Shopbot’s logo with a 90 degree V bit. It provides fairly clean edges, but the detail will be dependent on the sharpness of the bit and the material being cut.

All of the fuzzy wood chips could be brushed away with an old toothbrush.

Cutting the birch plywood produced very little dust. I ran the sample twice – once with a shop vac attached to the dust port and once without. In both cases there was no observable airborne wood chips or dust. Regardless, you should always wear respiratory protection, but I am not concerned about my computer being near a router.

With and without a shop vac for dust collection.

On Deck

The main limiting reagent is my lack of knowledge of VCarve Pro. The last time I used CAD, CAM, CNC, or any other engineering software my roommates were my parents. Thankfully Vectric provides resources on how to use the software and there are other tutorials on YouTube and Instructables. My attempts at making some other logos and text in plywood were met with failure. I am sure I will figure it out in due time. Or I will become so incredibly frustrated with it I will sell it on Craigslist. Either way.

I am not sure what projects I will attempt with my new tool. Suggestions are always welcome. I love the promise and bright future it offers.

Oh Snap!

Photobucket Pictures, Images and Photos

I certainly have no need for another old, lame magic trick like the snapper. I made the device so I could appreciate the lesson Roy Underhill provided when he made it on The Woodwright’s Shop.

The snapper could be made could be made by cutting the pieces first, drilling the hole, and then shaping it. You could drill the hole, shape it, and then cut the pieces. You could shape it, drill, and then cut. You could . . . as you see, Grasshopper, there are many wats to the tree. So, why do we do it the way we do it? We drill the hole first, shape it, and then cut the individual pieces because it is easier to work the wood as one unit. The lesson is in order of operations: leave it long, trim to fit.

Let us move from theory to practice. The wood is 3/4″ Photobucket Pictures, Images and Photos
And about 4″ long. Photobucket Pictures, Images and Photos

A 1/4″ hole is drilled in the center of the square end. Photobucket Pictures, Images and PhotosThe hole runs the length of the block. A 1/4″ diameter is used because that is the size of the dowel rod used to make the hook of the snapper.

One end is chamfered by cutting the corners with a saw. Photobucket Pictures, Images and PhotosThe chamfers were then shaped with a rasp. Photobucket Pictures, Images and Photos

The individual pieces were then cut. The body is 3″ long and the snapping end is 1″ long.

A small plug for the bottom of the body was cut from the dowel rod. Photobucket Pictures, Images and PhotosIt is glued in place with a rubber band. Photobucket Pictures, Images and PhotosAs the rubber band does not actually do any thing, there is no particular method needed to secure the rubber band in place. I simply shoved it in with the plug and glued it all with wood glue.

Notch the dowel rod to make the hook. Photobucket Pictures, Images and PhotosLike the rubber band, the hook serves no purpose. It does need to look like it could hook the rubber band though to sell the trick. The hook is then glued in place. Photobucket Pictures, Images and PhotosOnce it is dry, the dowel is cut flush with the head. Photobucket Pictures, Images and Photos

To use the snapper, squeeze the chamfered ends to shoot the end into the body. To make this entertaining you need to act like there is some skill and dexterity needed to hook the rubber band. Also, to make this entertaining, it helps if your audience consists of your young nieces and nephews.

Hello Sweetie

My wife enjoys Doctor Who and easily cosplays as River Song.

She also resembles a teacher who ignores the liability that comes with field trips.

For a Halloween present I made River Song’s journal.

The result I am hoping for.

I used TravelsAtNight’s video for guidance for making craft foam resemble leather.

My supplies include

  • Navy blue craft foam
  • Journal from Barnes & Noble
  • Blue Uniball Jetstream Pen

    My embossing tool

  • Blue Sharpie
  • Iron
  • Ruler
  • Foam brush
  • Dura Clear Gloss Varnish
  • TARDIS Journal Template

The cotton setting was too hot and the silk setting was too cold. Either setting would work if the iron was moved fast or slow enough. Rayon was the Goldilocks setting.

In my first attempt I used spray adhesive to adhere the template to the foam. I then ran the back of the pen over the template to emboss the foam. This did not work. The paper tore and the lines were very faint.

Instead I used the template as a scale drawing and laid out the lines with a blue ink ball point pen and ruler.

The back of my pen traced over the ink lines to emboss the foam.

The back of the pen repeatedly traced over the lines until the foam was embossed.

A blue sharpie went over the embossing. This covers any stray pen ink lines and adds contrast.

Crayola Markers do not work as the ink rubs right off.

A foam brush applied Dura Clear Gloss Varnish to seal the foam. After the pieces dried, spray adhesive was applied on the back of the foam and pressed onto the book. Weights were used to press the foam onto the book until the glue dried.

I also attempted to create the detailing on the spine with the foam. I was not satisfied with my results and ultimately ran out of time to fiddle with it more.

I am pleased with the final results, but I failed to take pictures of the journal. My wife did take a picture though and it is viewable here. I considered putting spoilers inside, but looking inside is against the rules. I would not want to ruin the Crash of the Byzantium.

Ricin to the finish

One of the greatest series in the history of television ended a few weeks ago. Before you continue reading this post, please note there will be Breaking Bad spoilers in this post.
While I am not surprised by debates of its meaning and other post game analysis, I was surprised to see people question the logistics of Walt poisoning a nervous, stevia addicted, tea fancying, methylamine supplier. This is the guy who built a meth empire, destroyed several ring leaders, had ten people killed in prison in two minutes, and jump started a RV with science.
Ricin is a poisonous protein from castor beans. It kills by shutting down the protein factories in your cells called ribosomes. The signs and symptoms a person experiences depends on how the poison is introduced to the body. If it is inhaled then the person will die of respiratory failure, while ingestion will terrorize the GI tract. Eating 5-20 castor beans can cause nausea, vomiting, diarrhea, tachycardia, and seizures for 4 days until your inevitable the death. There is no antidote and treatment typically focuses on treating symptoms and organ failure.
A stevia packet contains 1 gram of stevia. If you wanted to poison a 120 pound executive of a German conglomerate which owns a fast food chicken company, then you would need roughly 109 mg of ricin. With a LD50 of 20 mg/kg, if Lydia weighed 180 lbs you would only need 1.6 grams.
180 lbs * 1 kg/2.2 lbs * 20 mg/kg = 1636 mg
There is clearly enough space to accommodate the poison and sugar substitute. So how do you get the poison in the packet and reseal it?
I am not a sucrologist so I could not tell what the packet was made from. If it is plastic then you could cut it open, add the poison, and reseal it using an iron or other heating element. Not all that different than how it was made.

If it is a paper sachet then the glue keeping it closed could be dissolved with acetone or goo gone, the poison added, and then resealed.
So what would hinder this plan (aside from having the ethics to not kill people)? Not a whole lot. Ricin is very stable over a wide pH range and does not break down when exposed to UV light. If it is exposed to 80*C temperature for over one hour though it will denature and become nontoxic. Depending on the tea, it should be prepared 76*C to 100*C. The temperature is hot enough to render the ricin useless, but the tea is not likely to be at the temperature for a long enough time.
The biggest issue with the plan is making sure Lydia received a packet with ricin. There might be one stevia packet at the table or a waiter could be bribed to bring her a specific packet.

In conclusion, poisoning Lydia was a minor task for Walt. Let us go back to discussing color and its meaning in Breaking Bad.

Spear Me The Details

Last weekend I had an atlatl demonstrated before me at Wupatki National Park. If you own an dog you may have used this ancient device. After chucking a spear with the paleolithic device I came to the conclusion I should make one this weekend.

The plans come from Make Volume 12. There are many plans available on Instructables as well. It is simple to make and really only requires a handsaw, sandpaper, and layout tools. The build would go much faster with a jigsaw and sander though. If you want to channel your ancestors, then simply find a branch with a fork in it and you are done.

The lines are laid out

A relief cut made

The shape cut with a handsaw

1/4 inch hole drilled at roughly 45 degrees

1/4 inch diameter dowel that is about 1.25 inches long is glued in the hole. It could also be secured with sinew.

The spears were sharpened with a pencil sharpener

A small dimple was drilled in the back of the spear.

The spear is held between the index finger and thumb. The rest of the fingers hold the handle A hole is drilled in the handle for the index finger to go through per the design from Make. This seems unnecessary as it is not difficult to grip the spear without the hole.

Bohemian Gravity

Had I the ability to the sing I would have made this years ago. All I would have needed was the ability to sing. And know physics. And the ability to make sock puppets. But I could have totally made this years ago.

Awesome cover and physics lesson.

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