Friday, May 28, 2010
Monday, May 24, 2010
Sunday, May 23, 2010
This is the example that got me. The Arduino project .pde file is a test of an accelerometer library (Adxl345.cpp, .h). Here is what the directory listing looks like.
This yeilds the cryptic error
undefined reference to `loop'
undefined reference to `setup'
or both. The fix is to rename the Arduino project as anything other than "Adxl345". Using "Save As" in arduino should do the trick. This is what the listing looks like that works:
Friday, May 14, 2010
A simple test script is located in the examples directory.
Wednesday, May 12, 2010
Saturday, May 08, 2010
Along comes the 9 degree of freedom Razor IMU from SparkFun. This $125 bad boy has 3 axes of accel, 3 of gyro and 3 magnetometer, overkill for sure. I got this for experimentation and found out that it fit beautifully on Fin. The holes even lined up. This amazing foresight by Anool, enabled the sensor swap.
The 9 dof razor has a ATMEGA328 on board already. I reprogrammed the MEGA on the SharkFin base to be a digital slave dummy. It just listens on the serial port for 3 byte messages which it assigns to the digital ports: PORTB, PORTC, and PORTD. This simple interface could be expanded to also read digital inputs from the slave.
The accel datasheet indicates a selectable bandwidth. It is unclear on exactly how this is being accomplished, but if it is effective, this will relieve the huge burden on the processor of low-pass filtering the accel data.
The magnetometer offers the possibility of complete head orientation tracking. It is still unclear exactly how to take advantage of this given that there is no true velocity measurement. Ideas are welcome!
Saturday, May 01, 2010
I dropped off a word clock to Alden (creator of the miniature word clock). I had mistakenly come to the conclusion that Alden had a laser cutter. I will forward the super cool golden face plates when they arrive from Anool. You can see the word clock on the left of the work bench.
While I was there he showed me around his beautiful shop. This is a dream shop, well lit and spacious, with enough components on hand to invent the future (which is what he is doing!).
Below, Alden is checking the performance of a stepper driver he has been working on. The steppers must have gotten out of hand in the second photo as the whole room seems to be spinning.