Hi,
I've created an Arduino-style PLC using an 8-channel relay, Arduino Uno and timer. I need to add an 'analog tilt sensor' so that we can determine whether the PLC (or the unit which the PLC is installed in) is installed on a flat surface.
I have found digital tilt sensors but these will not work as it would only tell you extreme changes, I need to be able to detect to at least 2° accuracy, any ideas?
maybe an accelerometer/gyro can help - Arduino Playground - MPU-6050
Hi Robtillaart, thanks for the reply! I've tried an accelerator but unfortunately it does not work for my application. We are wanting to continual read the angle and relay this value to a database.
Kind Regards,
Mountaincows
"The ADXL345 is well suited to measures the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. Its high resolution (4 mg/LSB) enables measurement of inclination changes less than 1.0 degrees;."
where does the measurement fail?
unfortunately it does not work for my application
Then you did something wrong. You should have no problem measuring tilt angles to better than 1 degree accuracy (using some averaging).
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There lots of spirit bubble levels apps for smart phones. They all use digital sensors to get pitch and roll angles. The only analog tilt sensor I know of is a real world bubble level but there is no computer interface. 
I've seen level sensors that were nothing more than a potentiometer with a pendulum on the shaft, pretty accurate too.