lets make a change. i have thought about it and decided i need to slim things down a bit for testing of the circuits i am using this on before getting to complicated. Using atmel ATmega88 chip.
lets do the 3 sensors readings convert to real world values
(comment lines so that i can invert voltage ranges? if needed during testing. i do not know for sure if the sen 2 and 3 are 0-4.5v or 4.5-0v) use english not metric.
sen 1 temperature 80F to 240F 4.5v to 0.5 volt
warning level >= 190F
sen 2 temperature 80F to 450F 4.5v to 0.5 volt
warning level >= 220F
sen 3 pressure? p s i? 0 psi to 70 psi 4.5v to 0.5 volt
warning levels =< 8 PSI
fourth input activates readings 0-1 volt off? 1-5 volts on
cycle each reading non warning 5 seconds
update each non warning reading every 3 sec
display warning level readings imeadiatly and update reading every 2 sec. flash backlight when in warning ranges
display using LCD specified <[login to view URL]>. also each sensor use a seperate backlight.
comment all lines and i/o's used and needed
display readings using names:
sen 1 = "water temp"
sen 2 = "trans temp"
sen 3 = "oil pressure"
using a simpler code and starting point i can test this in circuit and then re-hire to build onto and expand the code to include memory, date, time, etc later on as they are tested and needed. so for the first contract just keep it simple for the above.
## Deliverables
attached is a sample/start of the pin outs and schematic. if you feel the pins can or should be different then make a note of what and why.