Showing posts with label Calculating. Show all posts
Showing posts with label Calculating. Show all posts

How close are we to doomsday? A clock is calculating it in real time

on Monday, April 1, 2013

neurotic armageddon by tom schofield

Tom Schofield created an installation artwork which visualises the ‘Doomsday Clock’, a symbolic clock maintained by an academic journal, ‘The Bulletin of Atomic Scientists’ which:

conveys how close humanity is to catastrophic destruction–the figurative midnight–and monitors the means humankind could use to obliterate itself. First and foremost, these include nuclear weapons, but they also encompass climate-changing technologies and new developments in the life sciences that could inflict irrevocable harm.

The artwork is composed by two pieces:

  • a small computer programme running on a server which ‘scrapes’ the content of the bulletins home page as often as possible. The software checks the current status of the clock and then sends the results over the internet
  • a small wall clock which receives data and displays the time of the Doomsday Clock on a red LED clock display. This process repeats as fast possible so that the device shows in near-real-time the status of the doomsday clock. 

The project uses an Arduino Uno board and an Arduino Ethernet shield and the clock is controlled with a MAX7219 Led control chip. Tom published  all the code and design for the indicator in his Github code repo  and told us he’s  very interested in the possibility that other people might make their own indicators. So, don’t be shy and give it a try!


 



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LED Wizard for Calculating Resistors and Drawing Schematics

on Thursday, January 31, 2013

This is a page I found extremely useful for calculating my resistors in LED circuits. You choose the number of LED's and the availiable source voltage and the program helps design the circuit for you. The nice thing about this page is that it also draws a sketch of the circuit* to build as a byproduct of the calculation:

(* be sure to click "wiring diagram")

http://led.linear1.org/led.wiz

To use the Wizard it might help to have the following data in lieu of the actual specifications of your LED's:

here's a table to help you make decent guesses:

For forward current you can use 20mA in most cases.

Color Voltage (Volts)
IR 1.5
red 2.0
orange2.0
yellow2.1
green2.2
true green3.3
blue 3.3
white 3.3
UV 3.3
blue (430 nm)4.6



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