Let's Make Robots!

IR LED's. blowing out

The 2 diagrams are cicuits for driving led at 38khz. I implemented both circuits. Firstly i take the second cicuit from the link and just add on the transistor part as seen in the first circuit. I did not add the 4.7kohm resistor nor did i add the 47ohm. Is that the reason why six of my leds are blowing out?

 Infrared555Schematic.gif

OR

the circuit over here http://marwww.in2p3.fr/~levansuu/projets_es2i/Parallax/stamps%20in%20class%20website/downloads/rob4.pdf 

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By the way, does anyone know how to measure frequency?

Your mulitmeter might have a setting for it. Or you could get/make a simple logic analyzer or frequency counter with a micro.

Just program a micro to count highs on a pin for a certain time period and maybe serial print it or display it on an LCD.

My multimeter doesn't and I don noe how to do it with a micro. D; U noe how to do it with a bs2?