Long Range IR LED.

Discussion in 'Embedded Systems and Microcontrollers' started by moorejohn90, Jul 25, 2012.

  1. moorejohn90

    Thread Starter Member

    Dec 9, 2011
    Hi, I want to make IR led and IR receiver (both of them are look like normal LED, IR LED is transparent, IR receiver is black color ) for making sensor for catching intruder. I bought it from electronic market of MYANMAR where I live.
    1- I hook up IR led like normal LED in one of Arduino's digital pin and ground.
    2- I hook up IR receiver LED as LDR with resister.

    I only got short range (not exceed 4 to 6 inch).
    I want to get long range ( around 4 to 5 feet).
    How do I get it.
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    U got to boost the IR emitter power.

    To do this u need to add some more IR LEDs. And use a power ful battery and u might need to replace the driver too.

    Or try getting a more power ful IR emitter
  3. moorejohn90

    Thread Starter Member

    Dec 9, 2011
    Hi R!f@@,
    I use the power from arduino's digital pin(5V). Am I need to apply more than. If I need how do I make it. IS it like driving 12 motor with transistor.
    And what is the meaning of driver in "u might need to replace the driver too."
    Thank for your immediately reply.
  4. takao21203

    Distinguished Member

    Apr 28, 2012
    IR LEDs are pulsed with high currents upto 100mA.

    Forward voltage is less than 1.5V

    You can't archieve 100mA from Arduino output.
    Even with no resistor, you get 70mA only + you exceed Arduino digital I/O specification (ATMEGA 328 etc.).

    You need a digital MOSFET (for instance).
  5. BMorse

    Senior Member

    Sep 26, 2009
    You can achieve higher current pulses from a 5 volt output by using an RS232 to TTL inverter IC such as the MAX232CPE, use the TTL side to connect to the arduino, and use the RS232 side to connect to IR emitter...... I used this scheme in a couple of IR projects and also with an Ultrasonic transducer to increase my output power.... Best part is, you do not need more than the 5 volts for power, since the MAX232 has its own charge pump to increase the TTL output up to +10 volts

    PLUS, using a collimating lens with the emitter will increase the distance.......
  6. moorejohn90

    Thread Starter Member

    Dec 9, 2011
    Hi I made my circuit as follow-
    1- Drive IR LED as normal LED -- Long side of LED pin to Arduino's pin No 13 and short side to Ground.
    2- Long side of IR transistor to Ground and short side to Arduino's pin No A0 and 10K resister pass through short side of IR transistor with Arduino's A0 to 5V. That all.
    By the way, I got IR light range up to 1 and half feet as I describe above :D . I got that info from "https://sites.google.com/site/therobotronics/arduino/simple-ir-detection-circuit". I think, the way of connecting IR transistor to Arduino was wrong (positive and negative because it is not like normal LED as describe in the above link) :p
    By the way, is any way to increase the light range to more than 1 and half feet(as I got).I don't have MOSFET yet. I will inform if it is work after I get MOSFET. :rolleyes: