Dear all .
AS we know Arduino Deumilanove board has 13 digital io and 5 analog ios .Total we have 18 pins.suppose I have 24 pins how can i reduce it to 18 pins.
Example: current configuration for my project
ds1307 is using 2 pins i.e A5 and A4 GPS receiver takes 2 pins DI0 and DI1 motor driver takes 4 pins DI(2,3,4,5) PWM controll takes 2 pins DI(10,11) heart beat signal takes 1 pin DI(13) feed back sensor takes 2 pin DI(6,7) motor speed selector 4 pins:8,9,10,12(http://in.element14.com/multicomp/mcrm4af-16r/rotary-dip-switch-smd/dp/1522038) mode change over selection:A3,A2 Sensor Slection: A1,A0
RTC reset require 1 pin gps logger require 1 pin debugger pin require 1 pin etc option.
IS there way to reduce pin selection without affecting above pin configuration
1)i thought of doing with resistor first in series with switch, But i found value read by port are not stable enough for selector switch wen subjected to high temperature. 2) i don't have any I2c based device expect RTC. else i could acccess using I2c protocol If any one has idea share it with links.