Helo!
Im really stuck with the analog readings on my arduino,i have an opamp circuit for water pressure sensor.The circuits gives an output voltage(between 1 and 3 Volts) depending on pressure differense.
http://www.practicalarduino.com/project … pth-sensor
The problem is that i cant get correct readings in the arduino input.The readings from pin which im using are changing all the time.
Sorry if these questions seem dumb, but it’ll help me understand where you’re up to.
Are the unstable readings occurring with the circuit connected, or when there’s nothing connected to the input?
Did you use multi-turn trimpots for the gain and offset controls, or regular trimpots?
Did you put any power supply decoupling capacitors on the circuit, such as 100nF monoblocks between GND and +5V?
Problem solved:)
I was using external 5 volt power supply for the circuit while the arduino was suppliyed by the usb! and i found out that the usb doesent give out stable 5 volt.So no i use arduini 5 volt pin to suply the circuit.
Hey Zyberb, that’s great to hear. Please let me know how you go, and photos would be great. I’d love to put a post on the Practical Arduino site about it - you can get me at jon@oxer.com.au.