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IR Widget

3/30/2008 - Anyone who wants to understand IR remote controls and how they function, this project will be great for you. This circuit I found online seems so simple and uses my favorite programmable chip company (Microchip). There really isn't a FULL tutorial from start to finish on this project online. So I will attempt to fill in the gaps and post my findings as I work through this project. - KC2NDA

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Parts List used for this project:

PIC 12F675 Microchip

2 x 1N4148 Diodes

1N4733A 5.1v Zener Diode (Radio Shack Part#: 276-565)

10K Ohm Resistor

2 x 1uF Tantalum Capacitors (2.2uF was in the original circuit, use this value if available)

IR Detector (I pulled this from an old DirecTV Hughes satellite receiver)

Click here to enlarge

Once the parts have been collected, the chip needed to be programmed. The PIC12F675 datasheet shows the pins needed to program the chip.

I used my PICKit 2 programmer to program the PIC12F675 microprocessor. I had to make a ICSP Cable for the 8 pin chip. Here is the standard ICSP pin outs:

ICSP Pin	Function	Description	PIC Pin
1	VPP/MCLR	Programming mode voltage. This must be connected to the MCLR pin of the target PIC. To put the PIC into programming mode, this line must be in a specified range that varies between PICs, but is always above Vdd. The highest maximum allowed Vpp voltage that we know of is 13.5 volts. There is no one Vpp voltage that is within the valid Vpp range of all PICs.	4
2	VDD Target	This is the positive power input to the PIC. Some programmers require this to be provided by the circuit (circuit must be at least partially powered up), some programmers expect to drive this line themselves and require the circuit to be off, while others can be configured either way (like the Microchip ICD2). The Embed Inc programmers expect to drive the Vdd line themselves and require the target circuit to be off during programming.	1
3	VSS (Ground)	Negative power input to the PIC and the ground reference for the remaining signals. Voltages of the other signals are implicitly with respect to GND unless otherwise specified.	8
4	ICSP Data/PG Data	Serial data line. The serial interface is bi-directional, so this line can be driven by either the programmer or the PIC depending on the current operation. In either case this line swings from GND to Vdd. A bit is transferred on the falling edge of PGC.	7
5	ICSP PCLK/PG Clock	Clock line of the serial data interface. This line swings from GND to Vdd and is always driven by the programmer. Data is transferred on the falling edge.	6