Hacked Gadgets Forum

February 7, 2007

RF Remote Controller

at 5:35 am. Filed under Complex Hacks, DIY Hacks, Electronic Hacks

This RF Remote Controller project is very well documented and even has a step by step explanation of what the PIC microcontroller code is doing line by line!

“On these pages, I will introduce Remote Controller with Radio Frequency. The electric wave sending-out is controlled with the code by PIC for transmission and the code is deciphered by PIC for receiving.

The 2 stages FET amplifier is used for the high frequency amplification. The FET amplifies only at the voltage to apply to gate (G). The resistor to be putting in the source (S) of the FET is to make the bias voltage of the gate. When making a resistance value big, voltage of the source goes up to the grounding and the bias voltage becomes big. In case of the gain of the amplifier is big, when the signal of the output returns to the input, an amplifier oscillates. In the case, it makes this resistance value big and the gain must be lowered.
The power of the FET connects with the center tap of the coil (L2 and L3) to be putting in the side of drain (D). This is to make do operation to have been stable, improving the characteristic of the resonance circuit. The characteristic of the resonance circuit is called queue (Q). The ideal resonance circuit picks up only a resonant frequency. However, the actual resonance circuit becomes a shape like the mountain which made a resonant frequency a top. When the Q of the resonance circuit is high, the voltage at the resonant frequency becomes high and the resonant characteristic becomes good.”