Friday, December 31, 2010

Vi Hart's Math Doodling videos

Vi Hart is a YouTube user and self-proclaimed mathemusician. She has made a number of really cool videos on doodling with math. They creatively show how math can be fun and interesting. I really like math, and the topics she talks are exactly what I like to give as examples of "fun math" (fractals, interesting relationships, etc).

Fast motion video of constructing Dudney's Dissection

Dudney's Dissection is a way to break up an equilateral triangle into four parts that form a square when rearranged. I read about it in How Round Is Your Circle?, which included instructions for how to mathematically construct it. I filmed my self doing so and sped it up 4x.


Make: Electronics book

This book has been published by O’Reiley Media, which also publishes Make: Magazine, a great DIY, “maker,” and hobby magazine. Make: Electronics is meant to be a new kind of introduction to learning electronics as a hobbyist. It teaches with “learning by discovery” and has the reader experiment and make mistakes, instead of just learning theory.  I agree with this method for learning and have experienced how this makes the book very good. It explains difficult concepts well and its atmosphere is very friendly.

Multiple people have said Make: Electronics is the new, main, go-to book for an introduction to electronics. Many people used to say this of Forrest M. Mimm’s An Introduction to Electronics. I own his book and did not find it very good. I found it quite advanced, abstract, and confusing. Even when I came back to it after a while I still couldn’t grasp some important concepts. I would strongly recommend Make: Electronics instead.

Note that if you want to get through Make: Electronics, you need to buy many tools and components. There are two kits you can buy from the Maker Shop that cover the parts for the first and second half of the book. This can be very helpful, but both of these kits cost about $100 each.

How Round Is Your Circle? review

Here is my previous post on this book and its website,

The subtitle for this book is Where Mathematics and Engineering Meet. This is a good summary of the book, as it looks at interesting ideas, concepts, situations, and problems in both fields, but relating both to the current topic. The major topics are on making accurately straight lines and round circles. Other ideas discussed are constant width solids (not always spheres), leaning stacks of dominoes, mechanical linkages, drilling square holes, and other irregular shapes, solids, and methods for doing physical, mechanical things.

I think the authors hit the nail on the head for a good topic to right on. The book appears to be interesting and written very well, and I plan to enjoy it a lot.

Some culture and values of maker/hacker community

While I'm not an expert on describing this concept accurately or from experience, I think it is a great thought and should be mentioned.

The large community of makers, hackers, tinkerers, inventors, experimenters, and explorers have a sort of unique mindset of what they do and why. They are not out to destroy (sometimes common definition of hacker), collect junk, or make impractical things. They want to learn, explore, innovate, teach, and help others do the same. From this mindset comes things like open source development, hacker-space communities, being self-taught and self-dependent, and fixing your technology instead of replacing it. You can imagine some of the benefits, such as an inviting, user-friendly way to learn and a strong method for developing and discovering new ideas and technologies. This is an amazing and interesting initiative and I agree with it wholeheartedly.

One thing I'd like to mention more thoroughly is the concept of being free to fix your own technology. Instead of just junking your broken toaster, toy, phone, or computer, try cracking it open and fixing it yourself. You'll save money and it's more efficient than recycling, and you might even have some fun or learn something (gasp!) as you figure out how the object works and how to fix it. It also gives you a sense of ownership and connection; as the maker saying goes, "if you can't open it, you don't own it." With this comes some "rights" that makers lobby manufacturers for and strive to use themselves whenever making or developing something. These are quite interesting and make some good points. I've attached pictures of two motto/creeds/listings of rights. One is the Maker's Bill of Rights by Mister Jalopy. The other is the iFixit Repair Manifesto. iFixit is a website that instructs people how to repair their broken iPhones, computers, etc. so that they can be reused.

I write this post after being reminded/inspired from my last project when I fixed our broken remote.

Monday, December 27, 2010

Fixing TV remote control

Today we fixed one of our TV remotes. The play button wasn't working when pressed (all other buttons worked fine, so we knew the batteries were ok). I thought it was either dirty button contacts or something electrical had come undone and needed to be connected back together. It worked again when we opened it up and cleaned the inside with rubbing alcohol, so it must have been dirty or dusty.

If you've ever opened up a simple calculator with rubber buttons, you can see how the buttons are part of one large rubber mold that presses on a circuit board underneath. The underside of the mold has black contacts that touch related contacts on the board when pressed. This bridges an electrical connection on the board and acts like a push-button switch. Our remote used the same concept. If the contacts are dirty, then the connection won't be strong and possibly won't work.

One interesting thing I noticed was "fixibility" of the remote. On one hand, it was very hard to pry open since there were no screws -- it snapped together. On the other hand, the circuit board was helpfully labeled on the inside, a strong hacker-friendly feature. My next post will be about why this is valued in the "maker" and "hacker" community.

Top cover removed

Rubber button mold

 Black button contacts

Circuit board top

Closeup of circuit board top. Notice contacts and helpful labels.

 Circuit board bottom. Notice the infrared light on left, which sends the signals to the TV.

Sunday, December 19, 2010

Posting Decline, Google's Autonomous Cars

Sorry that I haven't been posting lately, for anyone who reads this. I've been quite busy, but this Christmas break I'll be sure to post some more. I'm still following websites and writing down interesting ideas and day-to-day finds.

As a quick thing to post, here's the link for an article on Google's autonomous cars. This has been around for a while now and has become quite well known, so I don't think I'll make a real post about it. But it's still something good to know. If you want more, search for it and you'll find lots of articles and interviews.