SparkFun Forums

[jkraeme]

I bought a PNI MicoMag 3 + LIS3LV02DQ + uM FPU v 3.00 + Arduino to construct a tilt compensated compass heading with tilt numbers for a telescope project. I got each of the sensor working by themselves but was never able to get the entire suite running at one time. It was a lot of fun learning about SPI, I2C, and usb data transfers, but in the end I gave up. There were tilt compensated compasses but their price was a bit out of my range. I was interested to see that PNI has addressed that entire problem with their RM3000. I bought my MicroMag 3 from Sparkfun so there seems to be some level of commercial interactions.

The RM3000 has 3+3+3 axis measures with 3 axis accelerometers, a 3 axis gryo, and a 3 axis magnetometer. They do the full Kalman filtering on chip to provide jitter and drift free data. I was stunned to see that they were offering this sensor at $40 in single unit quantities. Having this sensor on a breakout board would address my problems in a single go. From the number of forum postings, I am not the only person who has attempted and been less that totally successful attempting to build a tilt compensated compass from piece parts.

Would you consider adding the RM3000 to your set of sensor breakout products?

Jim Kraemer

[Daniel Wee]

http://www.pnicorp.com/products/rm3000-rm2000

Daniel

[jkraeme]

Yep, that is the sensor I was talking about. I would like to be able to buy it on a breakout board for easy experimentation.

Jim

[UhClem]

Yep, that is the sensor I was talking about. I would like to be able to buy it on a breakout board for easy experimentation.

Jim

I don't see anything in the documentation about accelerometers or gyros. It looks to me like a 3 axis magnetic sensor only. In any case PNI already offers a $61 evaluation board.

[paul.c]

i believe jkraeme is correct. the rm3000 3 axis sensor suite does appear to fuse accerometers, gyros and magnetometers with a 'military' grade kalman filter.
download the data sheets and see for yourself. it also seems incorporated in the spacepoint tv device.

http://www.pnicorp.com/products/spacepoint-tv

I posted in 2006 lamenting the lack of fusion filters with sparkfun products and after months of trying ended up buying one from intersense which although expensive worked perfectly.
I'm glad to see things have changed since i last looked with the great work of sparkfun, Doug Weibel, Jose Julio, sebmagwick and others helping to bring cheaper more accurate sensor fused imu s to the masses.
I second jim kraemers vote for at least evaluating this product.
paul

[Inopia]

@paul.c: if you haven't already, have a look at http://code.google.com/p/imumargalgorithm30042010sohm/. I'm currently using it in conjunction with an IMU3000-EVB and an Ardupilot. The algorithm is much less computationally complex than the Kalman filter yet equal in quality, quaternion based, and does not require unreasonably high update rates. Code is included in both C and C#.

[paul.c]

cheers inopia

I have seen this and totally in awe with Sebmadgwicks work. I think i read in another post somewhere that he is working on a new version of his data logger so would be intersted in any news on that.

I'm in the planning stages for my next project and want to make sure I have as many options as possible so I don't leap in like I did last time and waste large sums of money and time on something that beyond my capabilities.

[UhClem]

i believe jkraeme is correct. the rm3000 3 axis sensor suite does appear to fuse accerometers, gyros and magnetometers with a 'military' grade kalman filter.download the data sheets and see for yourself.

From the SpacePoint document:

REQUIREMENTS
A complete SpacePoint® 3D Sensor System requires:
• Three 3-axis sensors
• PNI’s new patented Reference Magnetic Sensor RM3000*
• A 3-axis accelerometer
• A 3-axis gyro

The RM3000 is only a 3 axis magnetic sensor. I have looked at the RM3000 user manual which states:

The RM2000 is comprised of two Sen-XY Reference Magnetic Sensors (pn 12683) and a 3D MagIC ASIC MLF controller (pn 12927), and this forms the basis for a 2-axis (horizontal) digital compass. The RM3000 is the same as the RM2000 but adds a Sen-Z Reference Magnetic Sensor (pn 12779), such that compassing measurements are not constricted to the horizontal plane.

No mention of accelerometers, gyros, or Kalman filter.

[paul.c]

apologies David
you are correct.

I was confused by this:

http://eclecti.cc/hardware/easy-absolut ... -in-python

best
Paul