Tuesday, December 18, 2007

Other Projects life and the Helicopter.

My son (Paul A) spent the better part of the last two weeks helping some friends finish the plumbing and fixtures for a static firing. I went out Sunday to wire up some sensors and record data for the event. beyond that I can't talk about it much. All of the stuff Paul A and I were responsible for worked correctly. All the plumbing worked and I logged good data. Both Murphy and Marvin were present at the test. Marvin who??? Marvin the Martian of course, his favorite line "And right about now there should have been an earth shattering Kaboom!" It was nice to see everyone from FAR and work on a project with them. It was also nice as a father, to see skilled, competent, successful adults, impressed by my sons skills and work ethic. Being a father has been a hard job, but its nice to see that my son is starting to learn a lesson that took me at least 10 years longer to learn. Happiness and satisfaction can not be purchased. All too often we think I'll be happy as soon as I buy a new motorcycle,car, house,wardrobe etc... I'll be happy as soon as I'm promoted to manger, VP etc.... I strongly believe that happiness is earned by creating or doing something that has value. The sense of satisfaction earned by accomplishing something hard can not be oversold. I also think that the creation of tangible things with your own hands is of great personal value. You can not purchase this feeling.

While I was out at FAR waiting for other parts of the project to come together I flew the helicopter, the GPS finally works correctly in flight! Alas the Compass does not because the GPS antenna has magnets in the bottom and sits above the compass sensor. Arghhhh!


Henry said...

If the GPS antenna is like many that I have used, its lower surface is just a (stiff) sticker that you can peel off. Then the magnets are easily removed.

Paul Breed said...

I've spent the week diagnosing this problem. I test this by using a small hand compass to see what things on the helicopter are causing problems.

I removed the 2nd GPS antenna near the IMU and I relocated the rudder servo farther down the tail boom to get the magntic items away from the imu. The Hand compass sitting on top of the IMU now works correctly even with all the electronics running and the blades spinning.

Alas the IMU does not. So I'm working on Plan B and Plan C.
Plan B is to get the heading determination GPS working. I reviewed all the settings and physically checked the two antennas on the vehicle and discovered I'd entered the antenna separation parameter incorrectly. SO I will test that again today.

Plan C is to use an ocean industries magnetic heading sensor,which would be simple, but I'm out of serial ports on the flight computer and the ocean industries compass is an RS-232 device. I'm trying to use an NXP SC16IS740 to do serial to I2C conversion and I have that working, but the I2C ISR plays badly with others and I spent all of last night trying to resolve that.

(Trying to get heading with GPS)