1 reply to this topic

[RichardE]

I'm starting to play around with the analogue inputs but cannot figure out what the AnalogInput.SetRange method does. I looked at the tutorial for reading a temperature sensor, but the code does not use this method. The comments say that when you read the analog input you get 0 for 0V and 1024 for 3.3V (shouldn't that be 1023?). How does SetRange modify this behaviour? On a more general note - are there any documents describing the Netduino specific classes (such as AnalogInput)? I can find the Microsoft documentation but nothing on the stuff in the SecretLabs namespaces. Might need a book.

[MicroGuy]

I'm starting to play around with the analogue inputs but cannot figure out what the AnalogInput.SetRange method does.

I looked at the tutorial for reading a temperature sensor, but the code does not use this method. The comments say that when you read the analog input you get 0 for 0V and 1024 for 3.3V (shouldn't that be 1023?). How does SetRange modify this behaviour?

On a more general note - are there any documents describing the Netduino specific classes (such as AnalogInput)? I can find the Microsoft documentation but nothing on the stuff in the SecretLabs namespaces. Might need a book.

Just playing around with the SetRange it appears that it maps the 0-1023 raw adc count into a new range that you specifiy.
For example setting min = 100 and max = 200 would map a raw adc count of 0 to 100 and a Read count of 1023 would map to an Read count of 200.

Like this:
Raw acd Default Range SetRange(100,200) SetRange(500,1000)
-----------------------------------------------------------------
0 0 100 500
512 512 150 750
1023 1023 200 1000

Hope this helps