hello, kelly,,,,,,

about an year ago, i developed a project to get interface the PC ISA bus to read different linear inputs via ADC0804 and a 8 channel MUX 4051 to read the inputs using different sensors,
like yours,, i used LDR to sense the intensity of the ambient light, LM35 to sense the ambient temp., and Capacitive humuidity sensor to sense the RH % in air.
I used them with very common avalaible parts and it works satble and great without any noises,,,,

if you like , i can send you the schematic in raw form,,
i.e scanned image drawn by hand ....

let me know , if you are intersted,, it may solve ur problem...

bye...