- Wed Oct 25, 2006 11:08 pm
#21038
I am having trouble obtaining a stable output from this accelerometer. Looking at the signal on the scope shows a noise of 1.25Vpp. This is all very high frequency noise, up in the MHz.
I plan on using an active low pass filter to get rid of this. I am really only concerned with signals of a few Hz or less. This should solve most of the noise problems by itself. I was wondering though how other people have worked with this sensor? Its raw output is almost unusable, and because of aliasing, you can't average out the noise in software either.
The setup is on a breadboard with a PIC18F877A. The X,Y and Z outputs are going to AN0, 1, and 4 (I plan on using AN2 and 3 for Vref later, right now I'm reading 0 -> Vdd (5V)). The accelerometer is attached to about 8" of wire so it can be freely rotated without moving the breadboard. Plugging the accelerometer directly into the breadboard (no long wires) doesn't seem to make a difference.
I am using mikroC as my compiler. I have an infinite loop that reads each axis, converts the values to strings, and outputs them to an LCD. There is a 100ms delay in between cycles.
Any suggestions to help tame the output of this sensor? I have heard people say the Analog Devices accelerometers are more stable. I'm wondering if I should have gone with one of those.
I plan on using an active low pass filter to get rid of this. I am really only concerned with signals of a few Hz or less. This should solve most of the noise problems by itself. I was wondering though how other people have worked with this sensor? Its raw output is almost unusable, and because of aliasing, you can't average out the noise in software either.
The setup is on a breadboard with a PIC18F877A. The X,Y and Z outputs are going to AN0, 1, and 4 (I plan on using AN2 and 3 for Vref later, right now I'm reading 0 -> Vdd (5V)). The accelerometer is attached to about 8" of wire so it can be freely rotated without moving the breadboard. Plugging the accelerometer directly into the breadboard (no long wires) doesn't seem to make a difference.
I am using mikroC as my compiler. I have an infinite loop that reads each axis, converts the values to strings, and outputs them to an LCD. There is a 100ms delay in between cycles.
Any suggestions to help tame the output of this sensor? I have heard people say the Analog Devices accelerometers are more stable. I'm wondering if I should have gone with one of those.
