Is this IR remote circuit ok?

Discussion in 'The Projects Forum' started by Propaganda, Mar 19, 2010.

  1. Propaganda

    Thread Starter Member

    Jun 3, 2009
    This is just a simple IR remote control unit. The PIC16F616 generates a 38MHz signal, the BAUD is 2400, and the IR LED is a model#TSAL5300 powered by a CR2025 3v lithium battery.

    As you can see the two transistors (2N2222) create a AND gate which modulates the UART signal.

    Considering this is a battery powered application, the goal is battery life. Is the choice of using two transistors a good one? Should I go with an actual AND gate such as

  2. SgtWookie


    Jul 17, 2007
    There is no capacitor across the battery.
    There is no current limiting resistor for the IR LED.
    The AND gate you referenced is only capable of sinking/sourcing around 28mA.
    The 2N2222 transistor is rated for up to 800mA current. A more practical limit is 500mA.
    The MCU is powered 100% of the time. That might be OK if the sleep function is used heavily.