An Egg Spinner for Easter and High End Dumpster Diving

It is that time of year when Ophelia and I begin dying eggs.  We will probably do 3 dozen.  It is fun, cheap and a complete mess.  Just our kind of thing.

SO: This year, I am throwing something new into the mix.  

At the lab, we have automatic towel dispensers, that I discovered (after asking around a bit) are thrown away once they stop working.  I explained to the building manager that I would like any broken ones for robot parts - he seemed amused and was happy to save them for me.  Each one has a high torque 6V motor with all of the electronics that trigger and control it. (It turns out that the trigger is a capacitive antenna - like in a Theremin - see the long green thing in the second picture?  Also - it apparently takes 7 integrated circuits to spit out a paper towel.  But I digress…)  

The motor here is mounted inside a can and a bottle top has been glued to the gear that connects to the motor shaft.  It spins a little too fast; it wobbles a bit too much; but it is made completely of trash and it is very fun to use.

Happy Easter!

A Pixie 2 Transceiver for 80 meters, Just Because.

I got restless last weekend and made this.  It is my only anything for the 80 meter (3.579 MHz) band at the moment.  And it works very well.  For what it is.  And there is always someone beep-beep-beeping on 3.579 MHz.  You see, there is a “color-burst” crystal in every CRT TV that can be pulled out and used in this radio (see the little metal can? That’s it), so it is very easy to make a radio for that frequency.  I have not tried to send on the air with it yet, but I know it transmits (~450 mW).  

The Oscillators 

When I started out building radios, nothing I soldered together worked.  And I never knew why.  SO: I decided to practice building things in different ways, and practice something really fundamental, the Colpitts oscillator.   Oscillators are the core of all receiving and transmitting devices. This small circuit takes something that vibrates, like a quartz crystal or a tuned circuit, and powers and amplifies it.   AT ANY RATE, now that I am cleaning house, I am posting some early experiments and the crazy shapes they make on my oscilloscope before I cut them up into pieces and return their viscera to the parts bin.  So, thank you little crickets.  You taught me a lot.

The Small Wonder Labs SW+ 40 FINALLY enclosed

As a gift to myself for finishing my degree, I bought a ham radio kit from Small Wonder Labs (http://www.smallwonderlabs.com/) and  began putting it together.  (Logical thing to do, right?)  Now, YEARS later, it is finally complete and I have screwed it into the box.  The enclosure was a serial port switch box that I picked up at the MIT Swapfest for $2.  It was beige.  I stripped it and painted it a very dangerous shiny black.  As for the radio, the alignment turned out not to be difficult and I reckon I am putting out more than one watt.  Not more than two.  Tuning spans 36KHz (7.085 thru 7.121MHz).

The SW+ series is pretty amazing because it has been exhaustively documented and explained online.  There are not many electronics kits you can find with part-by-part descriptions of how it works.  (http://www.qsl.net/kf4trd/faq.html, http://www.k7qo.net/).

The radio has no dial or visual frequency display, so I soldered in the SWL “Freq-Mite” frequency counter.   When I push the button on the front, the transmit frequency comes into the headphones in Morse code.  Which is pretty clever.

Now, to improve my coding speed…

Taking Pictures of Snow.

This season we have has a few good snow storms.  If I pause during my shoveling, I can see the occasional perfectly formed 6 pointed snowflake fall on my sleeve.  I decided to take some pictures these little guys and but the problem is, I am warm, so they melt.

My first attempt to photograph them involved putting my scarf in the freezer for an hour and then taking it outside.  The scarf is cold, so they will not melt, and it is black, so they will show up in a photo.  This actually worked, but, under magnification, the scarf is bumpy, and fibrous.

Second attempt was with a piece of black plexiglass in the freezer.  This worked better, though it is glary.  I think a piece of very smooth matte plastic might be the ideal.

AT ANY RATE, here are the results.  The photos were taken with my Blackberry 9630 smartphone.  I hold a 10x Hastings triplet hand lens (loupe) (the kind you used in geology class) in front of the camera lens and the autofocus works right through the loupe.   

More later in the season.  Hopefully with some improvements.

The Temperature of a Whole Week’s Commute

SO: the best part of science is when you set out to describe something with a very firm idea in your head of what you will find and you end up with something completely different.  Well, here it is.  

I set out to look at the variation of temperature during my morning commute.  No surprise: it goes up and down as I move from warm inside places to cold outside places. (And the device to measure this *actually* works, which is no small deal).

What I was NOT prepared for was how utterly SUPER-IMPOSABLE every single day of the week is.  Seriously, some days almost to the minute.  

Big Discovery: I am a Creature of Absolute Routine.  I am not sure why seeing this measured so precisely is so unsettling, but it is.  I actually fancy myself pretty flaky some of the time.  But the data don’t lie.  As they say.  

Monday’s Commute

These are the first data: it worked!  When the sensor was hit by strong wind, the temperature goes crazy: as low at -59 F in one place.  I am not sure that is accurate.  AT ANY RATE: Boston is very windy near the river, so that accounts for the crazy fluctuation seen in the temperature once I get off the subway.  

More later as I collect a few more days.

Documenting my Commute

This is a device designed to measure the temperature of my commute once every second and record the data onto an SD memory card (like the ones used in a camera).  I have a grander goal - to measure the loudness of my commute - but this is a first try to get the hardware working right.  It uses an Arduino microcontroller board, the Adafruit Datalogger Shield and the TMP36 temperature sensor.  All the hardware and software &c. is available here: http://www.ladyada.net/make/logshield/lighttemp.html

Once I document my own commute, I am going to send the device around to others willing to wear it for a few days.  It should be fun.  Let me know if you are interested.

So far: it works!  I put the TMP36 sensor on the end of a cord so I can attach it to myself and not have to wear the whole device on my chest (and freak out fellow commuters (or transit police)).  The graph you see shows that the machine responds quickly to temperature changes and the data is easy to graph.  Next post: Monday’s commute.

The Larger Project:

I have long suspected that the stresses I experience during my commute to and from the lab everyday really impact just about everything I do.  Specifically, I think that the level of noise I encounter - buses, subways, city streets - is really quite high.  It is not that I am particularly sensitive, see, but I began to realize that I found complete silence rather jarring.  SO: I came up with a plan to figure out exactly how much sound I am exposed to.  The set up you see above will work well to capture the data from a sound sensor.  So far I have hacked together an electret mic element with two different pre-amps (one based on LM356 the other LM386), neither of which work terribly well yet.  Then I have to figure out the math on converting those data to decibels (any advice from Audio People reading this would be appreciated).  More on this shortly.

In Which We Plant a Forest in The Dining Room

One day the girls came back from the park with a bowl full of acorns.  Within a few days, some of them began to sprout.  I went to the hardware store and asked for a big pot.  Well, its winter already here in New England, so we found one, but we needed to climb around in the storage room to find it.  No matter.  We planted 15 of these acorns and waited for almost a month.  But the finally began to emerge.  I do not know how many more we will get, or how much more these will grow before they need winter to happen again (will a few weeks in the refrigerator trick them into growing again??)  At any rate, I am glad that some of the at least started to grow tall.  I figure in only 30 years, or so, we can split them up for fire wood. 

Laws of Physics Confirmed: Managing the Fuel Supply

Late last winter, I shattered the handle of the wood splitting maul and put off replacing it until, well, now.  After an hour of sawing and shaping and rasping and filing and banging and smashing and hammering - sparks flying, the whole bit - it is done.  In addition, it turns out, as predicted by the equation F=ma (and other more esoteric formulae), if one raises said maul above one’s heads and allows it to drop on a log, the log will split.

SO, you can rest easy tonight North America: by virtue of this simple, yet robust, confirmation of the fundamental laws of Newtonian physics, it is possible to infer that the sun will most likely rise tomorrow morning.