Lamba düğmesine LED

LED'in direnci R2 ve gerilimi V2 ise akım i=V2/R2 olur. 220V'yi V2'ye düşürmek için gerekli direnç R1 = 220V/i olur.

Yani önce LED'i seç, sonra LED'e uygun direnci seç. Lamba düğmesine monte et.

Argun'un oyuncaklarıdaki LED'ler AC ile çalışır mı? Sanırım hayır. Çözüm için link.

Deneme için fiş gerekiyor.

Köpek kovucusu

Mikrofon ile test et

Electric Grid

Yesterday there was power outage in many cities in Turkey. Build an electrical grid project with load balancing and also demonstrate cascading failure. Do this first as computer simulation and then use real parts.

Simple design with a DC relay demonstrating load balancing:

When a second resistance is connected in parallel, current increases to 2i. This increases the voltage in the relay to 2*Vr1 which closes the relay. When thre releay is closed, the second battery becomes part of the circuit (parallel to the first one). Both resistances will have a current of i. If these were light bulbs they would have the same amount of light output.

If we didn't have a second battery and the relay, adding the second resistance would decrease the resistance by half and cause the current to double which would empty the battery in half the time. What we achieved with our design is having the same electric output time.

Note that if we added the second battery in series, i2 would be 2*V/(R/2) = 4*i. Each resistance would have a current of 2i which could damage the appliance represented by the resistance (in our case, light bulbs).

Implementing the system with real parts would look like this:

Acoustic torpedo

http://en.wikipedia.org/wiki/Acoustic_torpedo

Tracker free video analysis and modeling tool

https://www.cabrillo.edu/~dbrown/tracker/

https://www.youtube.com/watch?v=La3H7JywgX0

Using Freelance

To get an idea about how useful a freelancer might be, do the following:

* The initial stage should be a prototype that can be finished in two weeks. It will be used to update requirements/design and decide on GO/NOGO

* You can specify the job as cloning an existing app. It should be doable in two weeks. Example: The puzzle game in Android. You could use the code produced to learn new things. Or you could ask them to clone Save My Cheese. It might give you fresh ideas about how to solve the problem.

ISS Globe

http://sciencehackday.org/project/iss-globe/:

"...the ISS Globe continuously shows you where the ISS is overhead. The team of sciencehackers used a translucent globe, two hobby servos, a MakerBot for 3D printing a few gears, a Teensy microcontroller and a laser that was mounted inside of the globe. Firmware controlled interaction between a laptop and the servos and a Python client controlled interaction between the microcontroller and the servos. The end product was a globe with a glowing red dot that would show you where the ISS currently was throughout the day."