I am a beginner at PIC programming and built a test circuit using the
16C84.  The circuit uses a magnetic switch for an input and when the switch
closes, and LED and piezo buzzer turn on.  Simple right?  Well, not for me!

Here is the problem:  when I physically move closer to the breadboard (with
the mag switch open), the LED turns on (but not the buzzer), getting
brighter as I get closer to the breadboard.  Once this happens, the
operation of the circuit is all messed up.  If I close the switch,
sometimes the LED goes on, sometimes the buzzer sounds, sometimes both, and
sometimes the LED works opposite, i.e. when the switch is open, the LED is
ON, and vice-versa.

Brief description on the circuit:  10 MHz Crystal (ECS) w/ 33 pF caps
directly to ground; PORTA<0> switch input, PORTA<1> led output, PORTA<2>
piezo output.
LED output feeds an 74HC04 inverter; output of inverter to LED cathode; LED
anode through 100 ohm resistor to +5V.  All unused 74HC04 inputs direct to
ground.  All unused PIC I/O are configured as outputs and left unconnected
to anything.  !MCLR pulled up to +5V.

As for hardware, I configure the I/O ports on reset, and basically run a
tight loop scanning the inputs, and changing the outputs based on the
input.

Any ideas?  Hardware or software?  I can't do much else until I figure out
what is going on here.

Thanks in advance for the help.

--John