extra IR leds

[shico90]

hello
i'm building a IR sensor and now i reached that the transmitter is sending and the receiver is receiver but i want to increase the intensity of the sender beam so i thought about adding about 10 extra IR leds
here is the ciruit i'm using
**broken link removed**
note:i'm using 5 V battery, is it better to use 9 V?, and what is better to use a regulator and transformer or an 9 v battery
thank you

 

[audioguru]

You must change resistor values if you use only 5V instead of 9V.

The SL100 transistor is available only in India. Since you want to drive 12 IR LEDs then use a medium-power transistor like a TIP31 and decrease the value of its base resistor so that the base current is 1/10th the collector current. Use 39 ohms.

With a 9V supply, 3 IR LEDs can be connected in series and with a 10 ohm resistor. Make 4 stings like this that are driven from the power transistor. You need IR LEDs that can pulse at 500mA.

Most IR receiver ICs require that the 38kHz pulses are in bursts with a pause after each burst.

 

[colin55]

Use a 9v battery and the two IR LEDs will give you all the range you need.