Category: Uncategorized

Idea: make a microcentrifuge using RC motors

The motors made for RC planes and cars are high speed and high power.

For example, the Turnigy Trackstar 1/10 12.0T 3300KV Brushless Motor, $23 specs are:
Kv: 3300
Max Voltage: 15v
Max current: 35amps
Watts: 550
Resistance: 0.0221Ohms
Max RPM: 50000

The load on a microfuge will be greater–22 tubes x 1.5 ml can be roughly 44g, figure a 100g total load with the rotor. So slower than max, but still quite fast.

High power ESC modules are sold to run these motors. So they take DC power, and a servo like signal (PWM), +5, GRD.

So a 10k RPM microfuge can be made with one of these motors + ESC, a servo for locking the lid, and a microcontroller to run it, take speed / time settings, and monitor and show the RPMs on a display.

Power could be from a PC power supply or a dedicated supply.

Setting up libcutter

On Ubuntu 12.04.

Downloaded from

It was hard to compile, requiring libsvg and several other libraries.
I added to the include directories:


include_directories(${PROJECT_SOURCE_DIR}/include/ ${PROJECT_SOURCE_DIR}/include/pub /usr/include/freetype2)

Download keys.h from:

#ifndef KEYS_H
#define KEYS_H
#define MOVE_KEY_0 1194338851ul
#define MOVE_KEY_1 1563510831ul
#define MOVE_KEY_2 992311905ul
#define MOVE_KEY_3 913389615ul

#define LINE_KEY_0 809461859ul
#define LINE_KEY_1 1902406960ul
#define LINE_KEY_2 1198081403ul
#define LINE_KEY_3 1832133993ul

#define CURVE_KEY_0 0x7D316E22ul
#define CURVE_KEY_1 0x4A4A7133ul
#define CURVE_KEY_2 0x5A3C5C5Ful
#define CURVE_KEY_3 0x78613A61ul

Full set of keys:

KEY0 - 0x272D6C37, 0x342A6173, 0x3663255B, 0x2B265A4D
KEY1 - 0x7D316E22, 0x4A4A7133, 0x5A3C5C5F, 0x78613A61
KEY2 - 0x47302A23, 0x5D31482F, 0x3B257A61, 0x3671382F
KEY3 - 0x303F6863, 0x71646D30, 0x4769457B, 0x6D342569
KEY4 - 0x45356650, 0x3A386D69, 0x575A7037, 0x335F357D
KEY5 - 0x343A2148, 0x614F3925, 0x753F6953, 0x47463626
KEY6 - 0x3F62626D, 0x7E555F44, 0x7E29425A, 0x52246268
KEY7 - 0x47302A23, 0x342A6173, 0x4769457B, 0x335F357D

Replaces include/pub/keys.h

./util/draw_svg ./util/svg_tests/Mini_DIY_circuit.svg /dev/ttyUSB0

Test run, worked!

Other options:
Freecut — Firmware replacement, haven’t tried.
Licut –Tried binaries and program compiled from source, did not work.

Cricut dissection, discusses the default blank cartridge.
ATX Hackerspace cricut page
Repair info
Build-to-spec Cricut Hacks Wiki (recovered from the Internet Archive)

Dinosaur coloration

In the last decade or so, dinosaurs have started being depicted as brightly colored. The reason for the trend of brightly colored dinosaurs in movies is that in recent years techniques for identifying pigments from fossils have been developed, using electron microscopy and ion bombardment mass spectrometry.

News report: Ancient Pigments Unearthed: Fossilized skin reveals the colors of three extinct marine reptiles by Ed Yong. The Scientist, January 8, 2014
Original article: (Abstract) Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles. Lindgren et. al., Nature 08 Jan 2014

and news report: Pictures: Dinosaur True Colors Revealed by Feather Find, Chris Sloan, National Geographic Daily News
Original article: Zhang et. al., 2010

Fossil color studies were pioneered by Jakob Vinther at Yale

No doubt movie speculation is running far ahead of the science, but these are the discoveries that unleashed the trend of brightly colored dinosaurs. At this point, it is reasonable to think dinosaurs are as brightly colored as birds or reptiles are today, and in some cases the coloring of specific species is known.

Ideas: sensors

Further notes on using digital camera sensors as high density multimodal sensor arrays.

1) Detect loading / strain using a module incorporating a strain sensor (e.g. the resistive type used in scales and strain gauges) to a diode. The diode is coupled to a fiber optic line that takes the signal to the camera.spectrometer.

2) Position sensors. Use an arc of partially clear plastic that has a light at one of the ends at the arc edge. A fiber optic line at the oriented normal to the arc gathers light that takes the signal to the camera. As the joint moves, the plastic arc moves and distance between the light and the fiber optic changes. This change is converted to a position.

For joints with 360 rotation, the arc of plastic is replaced by a disk. The light source is placed at the center, and an opaque radial line gives each position of the disk a different light intensity.

3) Touch sensors. Use my previous idea of an array of sensors embedded in a squishy and translucent layer with one or more light sources. Touch distorts the light path of direct or reflected light between the light source(s) and sensor in reproducible ways. The set of sensors is trained to recognize the pattern of light formed by different touches. The pattern may also be changed by movement of the surface, for example if the array of sensors covers a hand, and could bed used to detect hand position.

4) An array of fibers can be placed to collect light from a spectrometer. An array of spectrometers can be developed using this approach, as the camera can collect light from several 1D fiber optic arrays.

Library Ancient and Universal

Does there exist a project to assemble an online library of ancient written works intended to be complete? It sounds ridiculous, I know. But, if you start back far enough–say 3000 BCE–there is hardly anything to compile. And then the project can work forward until the project spreads out too much.

There are practical problems–images vs symbols and alphabets, fragmentary or derivative manuscripts, arguments over translation, historical translations versus modern ones, organization by region or language, but they have all been worked over by traditional publishers. The result would look like a cross proto-Project Gutenberg / Wiki.

If anyone tries this (assuming I just haven’t heard of it), I fear one of the most frustrating issues would be copyright. Museums forbidding the taking or use of images of the rare manuscripts or tablets or whatnot that they control.

It seems that most of the ancient manuscripts are described are referenced in fragments in medieval studies books and rare manuscripts. I hear about this stuff by third hand descriptions rather than by to links to online reference copies.

Update: Thesaurus Linguae Graecae (TLG)

Links for July 2013

FBI ignored plot to assassinate Occupy protesters
12 Very Real Voter-Suppression Tactics
Electro-Permanent cargo gripper
Electropermanent Magnetic Connectors and Actuators: Devices and Their Application in Programmable Matter by Ara Nerses Knaian
ALNiCo magnets
Sand resonance pattern video
MEAM waterjet, senior design project, 10k psi
Nothing About Abortion in the Bible
Iodine’s effect on IQ test scores–15 pts in iodine-deficient areas
Replacing Samsung SGH-T679M Digitizer
Silicon Valley (and the history of toxic waste)
Makers of Things
Human vestigial tail
A hundred proofs the Earth is not a Globe
History of Inequality
The Tea Party’s paranoid aesthetic by Kim Messick

App game idea

Flip it

This game board is an array of tiles. The tiles have letters. The game play involves flipping a pair of letters, as if the two tiles can move through the screen on the axis that connects them. In any case, they move switches them. The goal is to rearrange the tiles to spell words.

cat --flip c:a--> act
dog ------------> dog

cat --flip c:d--> dat
dog ------------> cog

The game can be played different sized boards, and with boards with cutouts.
Variation 1: Have the tiles have both color and a letter, to distinguish common letters.
Variation 2: Have the tiles be two sided, so that flipping them exposes the other sides.

What is interesting about this is that it is a class of games easy to implement in the computer but which is hard or impossible to implement as a physical game. There is a whole class of variations on pen and pencil or board games that haven’t been tried because of this!

How many liberal newspapers are left?

Saw in the news that the Seattle Times endorsed for Congress a Repub with ties to the militia/patriot movement–violent right wing nuts. I liberal Seattle has a hard right newspaper, how many cities have a Dem leaning paper left? I realize that Seattle has a big Defense industry economy, but that was my question.

newspaper political measure
from Gentzkow and Shapiro, 2010

I found this graph listing newspapers and giving them a score. I don’t follow enough papers to have a feel for how good a measure this is. I would place the Washington Post on the conservative side of the line, the NYT in the middle (painfully in the middle). Which doesn’t leave many liberal (or even Democratic) big city newspapers–the LA Times, Chicago Sun-Times, Denver Post, San Francisco Chronicle. I don’t know enough about the Atlanta Constitution, Boston Globe, or Philedelphia Inquirer to have a feel for their content.