Thursday, July 31, 2014

New Science Tattoo: The Periodic Table of the Elements on My Back

It is really difficult to get a good picture of your back.
It's the periodic table of the elements, and the simplicity of its structure is one of my favorite examples of scientific beauty.  Everything in our macroscopic world is made up of stuff in these boxes, and when you line them up by the number of protons like this, their columns (and general location) tell you quite a lot about their physical properties.

Other tattoos:
Just in case you were curious, here is a quick inventory of my other tattoos.  All of them represent the inherent beauty that comes from our ability to look at the universe, and build an understanding of it with only a few simple symbols.  To me, this is the prettiest art there is.

Right Calf:  The Schrödinger equation, and an electron trapped in a quantum well
This is the key to understanding how things behave at the subatomic level.
Right Foot:  The uncertainty principal
This captures the inherent randomness of our universe and our inability to observe it perfectly.  The irony is that this one is starting to rub off, making it difficult to observe.

Left Calf and Foot:  Pi, out to 51 digits
This ratio is fundamentally tied to the curious fact that our universe has more than one spatial dimension.
Left Bicep:  Maxwell's equations
These four equations govern all of electricity and magnetism.  Unfortunately for me, some assholes went and created a magnetic monopole in a laboratory, which violates the third equation, so now I have to go get an asterisk or something tattooed on there.

Left Tricep:  Electric field lines from static charges
A companion piece to maxwell's equations.  All the field lines start on the positive charge and end on the negative charge.
Left Shoulder:  Magnetic field lines from a bar magnet
Another companion piece to maxwell's equations.  Every line is a fully closed loop with no beginning and no end.
Right Ribcage:  List of martial arts I have studied
Taekwondo, kenpo, judo, wushu, muay thai, eskrima, and hapkido.  I have studied a lot more than just these, but these were the ones I felt most shaped my journey as a martial artist.  This is my only non-science tattoo, but this is still art to me because it reminds me that I live in a place where all these cultures come together, and I can learn a little bit from each of them.

Monday, July 28, 2014

Progress on James the Robot

"James the Robot" is coming along nicely, although I still have a few hurdles to overcome.  Who knew building a full scale robot training partner would be difficult?

James, gasping is disbelief.

Here are a few issues I am still trying to work out:

  • Right fingers are unresponsive - I'm pretty sure either the power or the ground is not making it all the way to the hand.  I'm going to have to take it apart and test it out.
  • Left fingers are jumpy - I'm not sure why, but it seems like the signal for one finger is getting picked up by the others as well.  This could be due to the fact that they all share a common ground and power housed in the arm.  I'm not sure how I am going to fix this yet.
  • Right shoulder moves the wrong way - the potentiometer connected to the servo in the right shoulder is backwards, so I need to detach it and put it on the right way.
  • Left arm spins forever on its own - The left arm just twists clockwise no matter what the potentiometer says.  It could mean the potentiometer is disconnected somewhere... I have to admit my soldering is not exactly professional quality.
  • Eyeball Y-Axis servo died - I'm pretty sure I burnt out this servo by setting it to a certain angle which was not physically possible.  I've burnt out like 5 of them so far by telling them to do something impossible.
Hands are difficult.  This is why most robots just have pinchers.

And just to make myself feel a little better, here is a list of what is working well:
  • InMoov Control Center software looks nice - The customizable software I wrote to control the robot with is about a third of the way done, and it looks great so far.  You can use buttons or sliders to position each servo, and it is pretty fun to control a robot that way.  Snapshots and actions are next.

  • The head works great - James can nod his head yes and shake his head no, and look left and right with his eyes, and open and shut his jaw. 
He's so melodramatic.
  • He has a voice - I connected a small speaker to a raspberry pi board for his voice.  You can type text into the command line, and it sends a query to the google translate server which then reads it out loud.  I didn't like the woman's voice, so I pulled the pitch down by 50%, and now he sounds like a nice guy.
James' vocal chords
Raspberry Pi... his brains

My goals right now are to finish the software, and (one by one) fix the problems with the servos.  I'd like James to be able to punch me in the face in a month or two, and I'd like to see how well he can swing an eskrima stick a few months after that.