@Acetronics
VERY good infos in AN thanks for sharing!
@ Scalerobotics
You have done excellent job That was exactly I was thinking to do trying oversampling on 12f pics! so you did the job for me THANKS!
So the conclusion is that we can use 12f675 ir 12f683 as I want to just measure an alt difference of 200m
I did some calculation and I have attaches 2 XL one is the previous 10,12,14bit calculation and bolded out the 200m measurements just to see what is going on and the second one is use pic 10bit ADC but with Dual AMP LMC662 (Acetronics suggestion) to give a narrow-window measurements and the resolution improved to about 4m .
Also attached a fast schematic of my thoughts (not checked , improvements are welcome!)
Final conclusion I take the amp route or MPX connected directly to pic (with oversampling). I think as I will only want to measure 200m difference. the pcb must/and can be kept simple (low weight) and low part count.
(dual amp trick: first subtracts 2.5V from MPX vout and the result is multiplied by 3 , so we have a range just from
0-2300meters but better resolution for 10bit pic adc -see AZAltitude10bit_DUALAMP.xls)
Scalerobotics about oversampling on 12f do you think you can 'go with' just the internal 8Mhz rc oscilator or it will not do the trick?!
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