If you're interested in Parallax's powerful 8-core Propeller chips, which are a huge step up from the Basic Stamps, here's some good news: a kind soul named Jason Wood has uploaded to the Parallax site a very complete Kalman-filtered IMU code object that uses the SparkFun IMU sensor head and this ADC. You plug the three components together, and the code gives you true Angle, Rate and q_bias. For those who have tried to write their own IMU, this is a Very Big Deal.

Basically, if you want to make a Propeller-based autopilot, Jason's done most of your work. No excuses now!

BTW, there are lots of other goodies in the Parallax object library, such as math libraries, floating point subroutines and PID routines.

Views: 2434

Comment by paul hubner on January 2, 2008 at 10:03am
Just rub in my snail's pace development why don't you!!
This is great. I'm reading the code now.

Hats off to Jason!

Now I've gotta get moving!
Comment by problah on January 2, 2008 at 10:06am
This is some hot code. I've been contemplating getting an avr based chip for my own project, but having this code available for modification, AND a chip that has higher functionality over your basic stamp, I may have to make a course adjustment of my own... yeah. That was geeky, but I said it.

On initial review of the code, it looks outstanding!
Great job!

Now the kicker.. how well can I program a parallax under linux...
Comment by Jack Crossfire on January 2, 2008 at 6:42pm
According to the block diagram each processor/cog has 16384 bytes of RAM in addition to the global 32768 bytes. Amazing not a single corporate entity has the imagination to do multi-core microcontrollers.
Comment by problah on January 3, 2008 at 9:41am
I'm still in debate on whether I want to use the Atmega128 on the Arduino controller, or try out this propeller. It's a tough call because the Atmel uses C and assembler, while the propeller uses their custom dev language, and assembler...and....I hate assembler.... 0]

So do I want to stick with an industry standard, or try out the propeller (Which seems to be getting more and more popularity)?

3D Robotics
Comment by Chris Anderson on January 3, 2008 at 10:37am

The only other thing I'd say in the Propeller's favor is that if you're intending to overlay telemetry in your video stream (known as OSD--On-Screen Display), the Propeller was designed to drive video with a single core and the video objects are already written and ready to use. This can save you the expense, weight and complexity of a stand-alone OSD board.
Comment by problah on January 3, 2008 at 11:19am
True, but at the same time, one OSD chip is only about 10 dollars, and if adding that extra chip, and some appendages overweights my UAV, then my UAV may be too small. 0]


But that is a very solid point, and I was thinking of that as well. But the problem is, does that alone justify switching to a different code development?
Comment by paul hubner on January 3, 2008 at 3:50pm
Take a look at my demo video. I don't use the Kalman code or sensors yet, but to my taste, the Parallax guy have it nailed. Video, sensors, telemetry and C&C all in one programming environment. I'm adding the overlay circuit now for my First person flight view.


Comment by problah on January 3, 2008 at 3:59pm
That's a pretty strong case you made there. 0] Man this is going to be a tough decision, allthough both items are cheap enough, I could do both, and compare. Heheheh.
Is your code available for the overlay, or are you making it proprietary? I would love to take a look at it.

PS: Nice Cockatiel (cockatoo?) going on back there. I have two kids and a dog that try to make noises like that all the time.

Comment by wayne garris on January 3, 2008 at 5:17pm
been playing with prop for a few months . this code looks awsome at first glance . was going to order that same imu in a few days lol looks like he did some major work i was dreading .
Comment by Jason Wood on January 8, 2008 at 4:11pm
What a great resource I just found here. I've been making robotics for ground based stuff up till now. I've been really thinking about making a UAV something. My IMU was designed for balancing applications but I plan on adding roll and yawn. Two things not really needed in balancing.

I appreciate all of your comments. It took me about 2 months to get that filter working 100%. My day job was getting in the way.

I want to do something with 4 rotor Helicopter.

Any one have a good direction to point me in?



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