I'm trying to build a vibration & shock analysis sensor device. I've interfaced adxl330 with pic16f877a adc converter. At the moment I'm trying to calibrate adxl330. I got reading from various orientation already as shown below. How do you convert them to Gs. Can someone post a procedure of doing this; Here are the readings.
I never use adxl, but I've use freescale's accelerometer and I think the calibration procedure is quite the same.
1. First you must find +1G. Its easy, find the maximum output voltage (point the axis toward the earth). Don't move for a while to make sure it is the static G that you sense and make a note.
2. Do the same for -1G except you must find the lowest output voltage.
3. Add the output voltage of +1G and -1G and divided by 2. You'll get the 0G output.
4. Done!
Sorry, I don't understand the value 608 512 396 etc. is it adc division or in mV? if its adc division, than the unit would be count/G. the value 512 is not accuratly in the middle, that means the value is not 0G. That's why you must find the 0G, by adding the max and the min from each axis and divided by 2. After you get the the 0G value, you should calculate the count/1G which is 0G-minimum axis value or max axis value-0G. The value of G is:
G=((ADC counts)-(0G Value))/(counts/G value)
e.g:
ADC shows 324
count/G = 106
0G = 502mV
so
G=(290-502)/106
G=-2G
Which means that the acceleration is 2G to the negative side
Sorry, I don't understand the value 608 512 396 etc. is it adc division or in mV? if its adc division, than the unit would be count/G. the value 512 is not accuratly in the middle, that means the value is not 0G. That's why you must find the 0G, by adding the max and the min from each axis and divided by 2. After you get the the 0G value, you should calculate the count/1G which is 0G-minimum axis value or max axis value-0G. The value of G is:
G=((ADC counts)-(0G Value))/(counts/G value)
e.g:
ADC shows 324
count/G = 106
0G = 502mV
so
G=(290-502)/106
G=-2G
Which means that the acceleration is 2G to the negative side
Sorry, I don't understand the value 608 512 396 etc. is it adc division or in mV? if its adc division, than the unit would be count/G. the value 512 is not accuratly in the middle, that means the value is not 0G. That's why you must find the 0G, by adding the max and the min from each axis and divided by 2. After you get the the 0G value, you should calculate the count/1G which is 0G-minimum axis value or max axis value-0G. The value of G is:
G=((ADC counts)-(0G Value))/(counts/G value)
e.g:
ADC shows 324
count/G = 106
0G = 502mV
so
G=(290-502)/106
G=-2G
Which means that the acceleration is 2G to the negative side
I'm beginner in using the ADXL330...
i use PIC16F877a.
my question is how the micro controller (PIC16F877a) send the desired signal to the sensor (ADXL330)? what the pin is to be actived?