i will show you how to make a led blink and use a usb port of the computer as a power source.
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Step 1: Materials

What you will need:
1] 555 timer
2] 1k ohm resistor x2
3] 100 ohm resistor
4] led{any color i used a green}
5] capacitor [depending on the blinking rate. see next step}
6] circuit board
7] usb male connector
8] 555 timer holder {whatever it is called}

Step 2: The capacitor

you can use any capacitor in the range of 10uf  to 1000uf depending upon the blinking speed.
if you take a capacitor of less value will blink the led faster.
if you take a capacitor of more value will blink the led slower.
i used a 100 uf capacitor.
Ploopy1 year ago
Do you have to program the 555 Timer Chip?
XOIIO3 years ago
its called an electrolytic capacitor, not electrolyte
robot1398 (author)  XOIIO3 years ago
wats kept in the spelling??/
XOIIO robot13983 years ago
uhg first off you dont make sense and I see this is a totally lost cause.
robot1398 (author)  XOIIO3 years ago
jensenr304 years ago
I like this design! it's cool to be able to make something out of with electrical components that works with a computer!

If you like 555 timers, check out this 555 timer calculator.

A Few Questions:
How much current does this thing draw?
Are you using a schematic program? if yes, which one?

robot1398 (author)  jensenr304 years ago
it draws about 20-25 mv
i did not use any schematic program.
i used paint to draw the schematic.
If your looking for a great schematic program that is free, downlaod CadSoft: EAGLE
Or go to their website:
robot1398 (author)  jensenr303 years ago
thanks for the software.
no prob
HarveyH444 years ago
To save a considerable amount of time and expense, you do realize there are LEDs with the flash circuit built in. The USB port can support 10 or so wired in parallel, and an interesting thing, is that they all flash at slightly different rates, which makes the seem to flash randomly.

There are more self flashing options these days as well, pretty much any color, alternate between two colors, RGB flash, RGB fade, and some amber that simulate a candle.

Only make mention, as there is much better chance of success, and save some money, in these tough times.