cannikin

I had the thought the other night that a very rudimentary way to figure pitch and roll without gravity would be to just watch the gyroscope for changes: if the gyro isn't changing then the actual rotation of the object isn't changing—any acceleration changes are happening purely because of acceleration and can be ignored. If they gyro IS changing then at least part of the acceleration changes are coming from actual rotation. How much is rotation and how much is acceleration is where a lot of scary math comes in.

What I'm trying to do is measure pitch and roll in a vehicle while it's moving, but without gravity being figured in. So if I'm driving up-hill it should report the actual incline angle of the road, not include additional measurements from the fact that I'm also accelerating up the hill. It seems like this would be a pretty common use case but I don't hear many other people complaining about it...

I played around with this board last night and it seems to be fine reading the I2C bus at 3.3V with no problem. I saw a comment not too long ago on SparkFun about using 3.3V level I2C and the commenter said the Arudino usually has no problem registering 3.3V as a HIGH. Here's someone quoting the datasheet: VIL Input Low Voltage, except XTAL1 and RESET pin Vcc = 1.8V - 2.4V MIN = -0.5 MAX = 0.2Vcc Vcc = 2.4V - 5.5V MIN = -0.5 MAX = 0.3Vcc VIH Input High Voltage, except XTAL1 and RESET pins Vcc = 1.8V - 2.4V MIN = 0.7Vcc MAX = Vcc+0.5 Vcc = 2.4V - 5.5V MIN = 0.6Vcc MAX = Vcc+0.5 If you were seeing an issue, SparkFun has a little breakout board that converts 3.3V line level to 5V (and vice-versa): https://www.sparkfun.com/products/8745

Wow, just found another one for $6.30! Not eligible for Amazon Prime but still ships for free: http://www.amazon.com/gp/product/B009TP5VOW

I've seen a couple posts on here asking about incline. Like this one in which Jeff gives a knowing smile at the end when he says the math is beyond him: http://www.i2cdevlib.com/forums/topic/37-incline-of-the-sensor/ But then in this one says the DMP is awesome because it can do those calculations for us: http://www.i2cdevlib.com/forums/topic/29-how-to-calculate-yaw-roll-pitch-from-mpu6050/ So I'm confused as to whether or not we can already calculate pitch and roll minus any gravity affects based on the current MPU6050 library in the I2CDev package? I thought maybe OUTPUT_READABLE_YAWPITCHROLL would provide those values but they definitely seem affected by gravity when I move the sensor around. There's a note above that constant declaration that says "this also requires gravity vector calculations" but I didn't know if that meant "requires you to do them yourself" or just that a note that they are required and being performed behind the scenes. Help me Jeff, you're my only hope! Thanks for the awesome library by the way!

Just ordered one of these the other day and it's working great! Much cheaper than SparkFun's at $40. It's got a regulator on board so you can give it 5v right off the Arduino and even has an LED so you know when it's on. Even ships 2-day for free if you've got Amazon Prime: http://www.amazon.com/gp/product/B008BOPN40 The comments section is actually how I found out about the site and Jeff's AMAZING work on making this thing accessible to everyone. (I promise I don't work for these guys, I was just happy to find one for so cheap!)