Tuesday, May 13, 2014

Planning a Course

I'm teaching two courses this summer. I have full control of the curriculum and of a budget assigned to the course for supplies. In the process I came up with a list of purchases that provide 'the best bang for your buck.'

Rapid Prototyping On the Cheap: Often in the classroom there is no access to advanced tools or expensive fabrication equipment. There isn't even access to the basic stuff sometimes. And finally, you often have to purchase it all ahead of time, which can be annoying for courses where the students are supposed to design something. Here's my list for cheap and versatile building materials. These can be great for science, robotics, architecture, etc. Nothing revolutionary, but it can be nice to have a list.
  • Foam board, paper products like cardstock, and corrugated plastic. With clever designs like T-beams and I-beams you can make these into formidable structures. If you can find a delivery dock willing to work with you, you can source all the cardboard you'd ever need. Or dig through a recycling bin.
  • Scissors, utility knives, and other simple cutting tools.
  • Hot glue. Don't forget to get a lot of glue sticks; they go fast.
  • Tape of all sorts. Scotch tape, masking tape, and duct tape are great. If you want something a little fancier, 3M sells filament tape in various flavors (different layouts of filament, different widths). Filament tape is a concept similar to ripstop fabric.
  • Popsicle sticks, and old favorite.
  • Straws are cheap and great for forming lightweight structures. The strawbee is pretty clever if overpriced. If you have access to a computerized cutting tool, just churn out a bunch of them yourself from a sheet of plastic.
  • Stiff wire. Don't forget the wirecutters.
Electricity and Magnetism: There are so many advanced and cheap experiments out there for E&M. Electrical components can be bought individually even from major distributors like Digikey or Mouser. It will almost always cost you less than buying some kind of kit. The selection from these major distributors can be overwhelming but with a little research (just look at what is in the kits) you should be able to master their very useful search tools and winnow the selection down to what you need.
  • Telephone wire is solid core wire. There are multiple strands in the main cable, each with its own color coded sheath. They work great with a breadboard. Specialized breadboard jumper kits are the biggest ripoff ever.
  • Copper enameled wire. It comes in a variety of gauges and is used for things like motor windings and speakers (making motors and speakers are very easy experiments to run in a classroom).
  • Velostat is a pressure sensitive material you can use to make cheap bend sensors. You can source a sheet from Adafruit and a variety of other sources online, depending on how much you need.
  • Magnets. Cheap good fun. I have found that Ebay is the best way to find cheap neodymium magnets. These ship from China so expect a slightly longer shipping time.
  • Foil, foil tape. Reflects light and heat, conductive, flexible. Great stuff.

Fancy Equipment for the Masses: This is a list of the more sophisticated equipment you can get that has really reached consumer level pricing.
  • Thanks to a spate of new designs funded by Kickstarter, thermoplastic and even resin 3D printing is starting to be available for as low as a few hundred dollars. The landscape on what is available here changes pretty quickly and there is a lot to consider, so you'll have to do your reading. Filament is available for as low as $30/kg in some colors.
  • Low cost oscilloscopes, function generators, and logic analyzers. Products like the Xmega Xprotolab and the Salae Logic Analyzer offer a lot of features suitable for many applications at very low prices.
  • Arduino is hugely popular and for good reason. It is a microcontroller on a board with friendly features that make it very easy to get started with. At the heart of the Arduino is a chip called the Atmel AVR (or in some cases, a more sophisticated ARM chip). The convenience and low cost of the Arduino boards mean that even experienced users often choose to buy the board rather than to make one themselves (with the know-how you can buy the AVR yourself for a few bucks, put some circuitry around it, and flash the Arduino bootloader onto it).
  • The Wixel is a $20 board featuring a microcontroller, wireless radio, and USB. There are lots of ways to add simple wireless capabilities to your project but the Wixel is one of my favorites. It is one of the cheapest solutions AND it includes a fully programmable microcontroller, so you can either use it as your all-in-one microcontroller solution or slap it on an existing development board like the Arduino.

Friday, May 9, 2014

Evil Product Design

This post will serve as the Hall of Infamy for product design. I'll update it as I find more examples. I don't own every product listed here, so some of my info just comes from product reviews and stories I find online. I actually put that line there because in light of the recent scandal where Mediabridge/Medialink lost their Amazon seller privileges harassing a critical reviewer, I don't want there a company threatening me for holding one of their products in poor esteem. These are just my opinions and my data might not be completely accurate!
  • An Optrel welding hood with planned obsolescence in the form of some 'non-serviceable' coin cell batteries encased in foam.
  • Dropcam is a surveillance camera that won't let you record locally. The hardware is $150 but you still have to pay $99 to $299 to use it with their cloud service. Here is a critical review from somebody who unwittingly bought the thing. It seems pretty obvious that they don't want you to use your own solutions for what to do with the video stream.
  • The general concept of selling one piece of hardware with different firmware installations at different prices. For example, oscilloscopes. If you could afford to sell me the hardware at that price, then you could afford to sell it with non-throttling firmware.
  • Back in the day when webcams were first getting popular and Apple was still trying to pit FireWire up against USB, my dad bought a USB webcam that was advertised as compatible with Mac. It was...but only if you forked over additional cash for the drivers by the same company that sold the webcam. There weren't generic drivers at the time, or at least most customers didn't know about them.
  • I went to a talk where the local fire station demo'd their equipment and it was really cool, but they dropped a mention of a yearly licensing agreement that they have to pay for the software and possibly firmware that go with the device. I was really confused and didn't get a chance to ask more questions, but I feel like something is amiss here. This equipment is specialty stuff, meant to work in extreme heat and with low failure rates (or certainly I should hope so!), and it is probably very expensive already. Nickle and diming the taxpayers for some of the simplest software and firmware out there (all it does is tell you how strong the strength is from the wireless pinger on the firefighter suit to the magic wand)? I wish I could be more angry at the company but some of that anger has to be directed at the (faulty) system by which our government chooses contractors and suppliers of equipment.

More to come.

Friday, May 2, 2014

Magnetic Palago tiles

These are magnetic Palago tiles. They are laser cut from 1/2" poplar. Disk magnets are embedded in the sides with alternating orientations, ensuring tiles are placed correctly, and also preventing accidental movement of the tiles during gameplay. The tiles are painted metallic blue and finished with polycrylic.

Thursday, May 1, 2014

Product Photography

I finally got a setup going for product photography. The goal is something reasonably good that can be done without too much fuss. I made some bracelets too so here are some shots.