June 14, 2009
about 5 years ago
Is it really a great idea to resell these? Technically they are counterfeit goods, so aside from the legality, what’s to stop people buying a whole heap of ‘ATMega328s’ for the bargain price of 50c here and reselling them elsewhere? I can see SparkFun has gone to great pains to point out these are fakes, but other ‘sleight-of-hand professionals’ might not be so helpful…
about 5 years ago
It’s not an AHRS… yet.
Given there’s essentially an Arduino built into the board with full access to the sensors, it’s only a matter before the IMU code from the open source ArduPilot project is integrated into this board to provide AHRS capability at no added cost (in fact, see http://www.diydrones.com/profiles/blogs/new-imu-from-sparkfun-soon-to )
I must still insist that 9DOF is incorrect - adding a 3-axis magnetometer does not increase the number of degrees of freedom that this board can measure, because in 3 spatial dimensions there are only 6 degrees of freedom in rigid body motion. It is confusing because there are physically 9 sensors on 3 axes, but a sensor is not equivalent to a degree of freedom (otherwise adding 3 temperature sensors would make it a 12DOF IMU…)
I suggested AHRS because they require 6DOF inertial sensing as well as 2 orthogonal reference vectors (gravity and magnetic field), and this board provides all of these.
To beat the old drum… As an engineer, it grates against my soul to see this advertised as 9DOF, when it is in fact only 6DOF (maximum possible in our 3 dimensional world) plus a yaw reference. The breakdown is as follows:
3 Accelerometers: 3 linear DOF (+ gravity vector)
3 Gyroscopes: 3 rotational DOF
3 Magnetometers: magnetic north vector
I suggest that this be advertised as an AHRS board (Attitude and Heading Reference System), in contrast with the original Razor IMU (which you might call an ARS or Attitude Reference System, though no-one does). Unfortunately, 9DOF is already on the silkscreen grate grate :P
No public wish lists :(
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