Hey got a quick question. I hooked up the ADXL322 +/-2g which is rated at 420mV/g. It is hooked up to a 5V power supply. At level surface I get a reading of 500 from analogRead which is about 2.5v. When I tilt the accelerometer forwards on X axis to 90 degrees I get 790 and the other way 420.
Now here comes the confusion to me. At those angles are those the values for +-2G? This would actually make sense since 420mV/g is about 86 on the analogRead value. Why would it read +-2G if earths gravity is 1G. Also when I tap the accelerometer when it's tilted it gives me greater values up to 1023 (5V) suggesting that it is only reading 1G when its tilted since it is a 2G meter.
So in conclusion is a -+2G (430mV/g) @ 5V meter 0V=-2G, 2.5V=0G, 5V=+2G OR -2G = 1.64V ,0G = 2.5V, 2G = 3.34V
if it's the lather , why the heck does it read more than +-2G when i tap it when it's tilted!?? Maybe it the tilt AND +- 2G which would still be in the 5V range.
I hooked up the ADXL322 +/-2g which is rated at 420mV/g.
According to the data sheet, the ADXL322 is only rated at 420mV/g when the supply voltage Vs is 3V. It says the sensitivity and zero-g bias level are essentially ratiometric to Vs, so I think you need to scale those specs if you're using Vs = 5V. Also, note that the unpowered maximum rating for this sensor is 10,000g, so you'll want to take care not to exceed that ;D
Thanks for the quick reply. So what you are saying is that 1G = 420mV @ 3V. So in that case at 5V is should be at 700mV/g. Voltage at 0G at 3V should be 1.5V and at 5V should be 2.5V. This is what I have. So I am going by 700mV/g or ~143 per G on the analogRead function. That still doesn't max out my range as 1.5V + 1.4 V = 2.9V which should be +2G at 5V. RIGHT? ;D
i've tuned mine to 45mV/G, so i get 1000 (1G) when vertical, and -1G when inverted, but my problem is when i shake it with my hand, it reads sometimes up to 3G, and the sensor is only rated +-2G. Is this possible?