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[on:]

hi all!
i'm going to make a strobe light (like the ones used in disco) , but using an array of led, and have it controlled from arduino, so i ran in the following questions:
1) it's better to use a timer like LM555 or just power on/off trough arduino code ?
2) which kind of led would be the best ? an array of 20-30 "super bright led" , or just some "high power" (1W/Led) ?
I also need them to be switched on and off at relatively high frequency, and the should not burn after little use
3) To "drive" the led/led array, it's better to use a transistor, or not ?
thanks in advance to all who will help me

[Reply #1 on:]

it's better to use a timer like LM555 or just power on/off trough arduino code ?

No need for a timer, the Arduino can do that. However the 555 can do it as well and it only costs about 30c. Use one or the other but no need for both.

To "drive" the led/led array, it's better to use a transistor, or not ?

You will have to use something, the 20-odd mA available from an Arduino output pin won't drive much. A transistor will do the job.

[Reply #2 on:]

I also need them to be switched on and off at relatively high frequency, and the should not burn after little use

Switching at high speed is no problem and will not contribute to excessive strain on the LEDs or the drivers.

? an array of 20-30 "super bright led" , or just some "high power" (1W/Led)

The collection of small LEDs is easer to cope with as the power dissipation is distributed and you can use resistors as current limiting devices. With a power LED you have to have constant current drivers which are more expensive. Also you have a lot more heat concentrated in one place that has to be got rid of using heat sinks.

[Reply #3 on:]

thanks a lot i just ordered a 20 pack of UV leds (to see if we can make fluorescent thing glow ) and now i'm going to pick up some packs of relatively cheap leds (but with at least 10000 mcd)  and see what comes out

[Reply #4 on:]

.. and don't forget that UV LEDs have a forward voltage around 4 volts, being super-blue so to speak...