you can use PIC micro controller * PIC18F4620 -- has 13 analog inputs -- Wouter van Ooijen recommends that hobbyists use the largest and most capable chip available[1], and this is it (as of 2006-01). ~$9
* PIC16F877A -- the largest chip of the 16F87x family; has 8 analog inputs -- recommended by Wouter (#2); AmQRP; PICList. ~$8
* PIC16F88 -- has 7 analog inputs -- recommended by AmQRP; SparkFun. ~$5
* PIC16F628 -- Cheaper than the PIC16F84A, with a built-in 4MHz clock and a UART, but lacks any analog inputs -- recommended by Wouter (#3); AmQRP -- ~$4
* PIC16F1936 -- 11 ch, 10-bit ADC; two indirect pointer registers; XLP (extreme low power) ... recommended by some people on the PIClist as a faster, better, cheaper replacement for the 16F877. -- ~$3