Picture of usb powered blinking led
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

Picture of 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

Picture of 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.

Step 3: Solder the circuit

Picture of solder the circuit
here is the circuit digram . solder the the circuit according to the digram.

Step 4: Connect the usb connector

Picture of connect the usb connector
we will need only the red and black wire.
my connector had red and a blue wire.
connect the red wire to the positive terminal of the blinking circuit.
connect the black wire to the negative terminal of the blinking circuit.

Step 5: All done

Picture of all done
if you like the instructable follow and plz rate and please please vote for the 3rd epilog challenge
 my e-mail id is
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)  jensenr304 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.