Know How... 70

We're making power with thermocouples and it's time to organize your ripped DVD collection.

Making News

If you've ever wanted to make a Raspberry Pi computer, but thought it was too hard, there's a new Kickstarter project called "Kano." Its goal is to make the Raspberry Pi as simple as a Lego project. You learn to code games like Snake and Pong to get into coding as well.

In other Raspberry Pi news, Mathematica and Wolfram Language will be free for the Raspberry Pi. Those are super-powerful programs -- free is a great deal.

Making Power with FIRE!

In episode 65 we explained how the "Seebeck Effect" allows a thermocouple to turn heat into electricity. When two different types of metal are joined (via soldering, welding or clamping) a heat source will cause them to expand at different rates, generating a small electrical current. That same device can be used to move heat from one side of the junction to the other when an electrical field is applied to the thermocouple, using a principle known as the "Peltier Effect."

Combine many of these thermocouples into a single unit and you have a TEC or TEG. (Thermo Electric Cooler / Thermo Electric Generator). Both of these devices can take advantage of either the "Seebeck Effect" and the "Peltier Effect" to alternatively heat/cool or generate electricity from a heat source.

TEGs differ from TECs in that it can handle much higher temperatures than a TEC before failure.

Parts List

• TEC (ThermoElectric Cooler) or TEG (ThermoElectric Generator)
• Heat Spreader
• Heat Sink/Heat Removal Device
• Thermal Compound
• Heat Source

Assembling your Power Generation Unit

• Coat the TEC/Heat Sink/Heat Spreader with a THIN coat of thermal compound. This is to ensure efficient and EVEN transfer of heat from the heat spreader into the TEC/TEG, into the heat sink.
• Mount your TEC/TEG between the heat spreader and the heat sink. You want an EVEN mounting, any gaps or uneven mounting will cause heat to build up in on part of the element, causing early failure of the unit.
• Wire your TECs/TEGs in series or parallel. In series (negative to positive) your TECs/TEGs will add their voltage to the total voltage availible. Each TEC/TEG will generate ~1.5 volts and a few hundred ma. In parallel (positive to positive, negative to negative) your TECs/TEGs will increase the amperage availible. - Know your application before wiring!
• Cool the "Cool Side" - The power generating capacity of a TEC/TEG assembly will depend on the "Delta T" - or difference in temperature between the hot side and the cold side. Try to make the cold side as cold as possible to maximize power generation.
• Heat it up!

Organizing your ripped DVDs in Media Center

If you like having your DVD collection in your Media Center organized, you might want to try out MyMovies. It's a free plugin for Media Center that will pull in metadata for the DVDs you've ripped. MyMovies can even act as a database for your *shudder* offline DVDs.

We're going to stick to the DVDs you've ripped, though. (To find out how to rip your DVDs, check out Know How... 22.) Download MyMovies. You'll open the MyMovies Collection Management app on your Windows machine. From there you'll add your DVDs by hitting "Add Title" in the toolbar. Then select "Import Folders" and browse to your DVD folder. MyMovies will attempt to find the metadata for your video.

If MyMovies doesn't automatically find the correct data, you can find the title on IMDB. If you take a look at the URL of an IMDB title you'll see something like www.imdb.com/title/tt0103359 - you can input the "tt103359" number in MyMovies for identification. This is pretty useful for remakes. If you make changes to a title, make sure you hit "Save Title" on the bottom of the program to save your progress.

When you're done with importing all your information, make sure you backup your database. You'll thank yourself later.

Chrome Keyword Quicktip

Did you know that you could call up your favorite sites in Chrome using keywords? It's not a well known feature, but it's hidden in the Manage search engines pane.

Find a site you frequently visit and copy that URL (this tip makes the most sense for long domain names or Google Drive documents). Go into your Chrome Settings, then click "Manage search engines..." Then scroll all the way to the bottom of the list of search engines. You'll see three fields. Add a name for your favorite site in the "Add a new search engine." Put the URL in the "URL with %s in place." Then choose your keyword that will let you call the URL from the address bar. Hit done.

In our case, we wanted to load a Google Drive document. I gave it the keyword "hpx." Now, when I type "hpx" in the address bar, the website will load. In general, this can save you time since you don't have to remember long URLs and you don't have to find them in your bookmarks folder.

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