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PIC16x84 programmer

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IR Link Hardware

The New Circuit:


Notes on the schematics:

  • The circuit has been changed. The old circuit still available.
  • The new circuit has a better pin allocation which makes it easiyer to implement and build. It has also support for 2 IR LEDs, each one controlled by a pin (thus 25mA is source in each IR LED).
  • The 4MHz crystal with the two 22pF to 22pF capacitors is equivalent to a 4MHz resonator.
  • The circuit can be powered from a 9V battery, since there is a +5V voltage regulator. It can be also powered directely from a 4.5V flat battery (without the use of regulator). A 4.5V battery has a long life and is cheap, but a 9V one is more portable.
  • A PIC16C84 or a PIC16F84 can be used. However a PIC16F84 is better and cheaper. When programming a PIC16F84, make sure you set the fuses to: XT, WTD_ON and PWR_ON. You can also have Pre-Programmed PICs from me.
  • Don't forget to download the LITE code for the PIC from the Software downloads section.
  • In the LITE version there is only one switch used. The other switch is only useful in the STANDART version.


  • Resistors: 330 Ohm, 470 Ohm, 2 x 120 Ohm, 2 x 18k Ohm, 2 x 47k Ohm.
  • Caracitors: 4.7 uF (Tantalium electrolyte prefered), 33uF Tantalium (equivalent to 100 uF if normal electrolyte capacitor), 0.1 uF (Tantalum electrolyte prefered).
  • 4MHz crystal oscillator with 2 x 22pF capacitors, or a 3-pin resonator.
  • Diodes: 2 x 1N4148, any RED LED, 2 x IR LED (see below).
  • Voltage Regulator: LM2931. A 78L05 regulator can be used, but you should be careful choosing other capacitors values.
  • IR Reciever: SFH506-30 or SFH506-33 from Infenion/Siemens
  • The IR reciever module: The essential part is the SFH506-30/33 from Siemens. The SFH506-30 operates at 30khz and the SFH506-33 at 33kHz. The PIC program changes according to which SFH506 is used.
    This module can be purchased in many places. Check the 
    Pre-Programmed PICs page.  

    The IR LED: Any IR LED that has a wavelength of 950 nm can be used instead of the SFH415 from Siemens. In the Datasheet of the SFH506-30 they say that with the SFH415 a range up to 34 m can be obtained.  

    Extending the range: To extend the range, multiple IR LEDs can be connected in parallel, the same way as the IR LEDs are connected. Note however, that the output current of the PIC is limited to 25mA (This can be solved by using a transistor, but this descreases the battery life).


    Using a PCB: For using a PCB or a strip-board, check the old circuit page. Check the PCB designs by Thomas Koglbauer and Antoine Mercier. In order to use the new circuit, those designs need to be modified a little bit.

    PICs & Kits page contains a PCB image of the PCB that is found in the kit, which uses the new circuit:

    Back to index.  
    Author : Sami Khawam