When I saw the HMC6352 you carry I couldn’t believe the miracle. The device is fantastic. But when you have it on a helicopter you soon discover it is very tilt sensitive (as any 2-axis compass). This easily makes for 30 degrees error. I searched the net and found a tilt-resistant integrated 3-axis compass chip with I2C interface!
Seems ALPS has the ultimate solution once and for all times. I strongly suggest you carry that one, too, if it is available.
By the way: Since successfully suggesting the Bluetooth modules to sparkfun, I regularly checked the site and must say: You do a fantastic job of updating your offer! Keep on amazing me!
I am currently designing and testing a tilt adjusted compass to determine the azmuth (direction) and elevation (tilt) to allow an amateur astronomer to aim handheld binoculars. Most sky map programs determine the exact time using internet time servers. The exact latitude and longitude can be determined by GPS or on-line mapping programs. By providing the Az-El of a particular object in the sky, you could locate the exact object you are pointing at. (A bit easier than learning the sky from scratch for absolute beginners.) Alternately you could watch the screen on your laptop until you line your binos up with an object on the map. That capability is not built into even top end binos. The mount for my telescope, for example, is about four feet tall, and is constructed 1/2" steel wall pipe. It took 2 people to move it into my observatory. It is VERY stable, but hardly suitable for binoculars.
My hobby-only prototype uses a MicroMag3 3-axis compass, a LIS3LV02DQ accelerometer, and a FPU v3 math chip I purchased from SparkFun. By the way, the trig behind the tilt adjusts has been fun. It brings back my old Fortran programs I wrote in undergraduate CS classes. Since the project is a pure prototype I am using a Basic Stamp 2, but I am experimenting with the ATMega16 on one of your USB Audrino boards. My current prototype uses all the space you get on an experimenters version of Eagle. My final goal is to shrink the entire circuit down to a playing card. A one chip solution would be an interest alternative to cut the size, power consumption, and board complexity to more workable levels.
This chip would even be interesting at the $100 level due to the large number of components that could be remove from tilt adjusted compass solutions.
I discovered your comment (below) when I was looking the Spark Fun site over. I am interested in a project much like the one you have described. Indeed, I started planning to fit a sensor package to binoculars so as to allow the measurement of directiom, geographic location, time and tilt of the binoculars, with that information being processed to identify the celestial object being targeted. I’ve since decided to replace the bincoulars with a green laser pointer. I’m imagining a small handheld device that allows one to point at a sky object and readout on a bluetooth coupled PDA the object’s names, catalog IDs, etc. This is a takeoff on the Celestron “SkyScout” idea.
I’ve been looking at various sensor development kits trying to find one that includes an adequate PIC processor to allow the other sensors to communicate through it, and to couple that processor to a bluetooth transceiver. I have lots of experiance with sensor design but little with electronic design, and so have been hoping to be able to modify an existing evaluation product as needed.
Might you be interested in considering some sort of collaboration, or even just a “devil’s advocate” discussion of this challange?
I am currently designing and testing a tilt adjusted compass to determine the azmuth (direction) and elevation (tilt) to allow an amateur astronomer to aim handheld binoculars. Most sky map programs determine the exact time using internet time servers. The exact latitude and longitude can be determined by GPS or on-line mapping programs. By providing the Az-El of a particular object in the sky, you could locate the exact object you are pointing at. (A bit easier than learning the sky from scratch for absolute beginners.) Alternately you could watch the screen on your laptop until you line your binos up with an object on the map. That capability is not built into even top end binos. The mount for my telescope, for example, is about four feet tall, and is constructed 1/2" steel wall pipe. It took 2 people to move it into my observatory. It is VERY stable, but hardly suitable for binoculars.
My hobby-only prototype uses a MicroMag3 3-axis compass, a LIS3LV02DQ accelerometer, and a FPU v3 math chip I purchased from SparkFun. By the way, the trig behind the tilt adjusts has been fun. It brings back my old Fortran programs I wrote in undergraduate CS classes. Since the project is a pure prototype I am using a Basic Stamp 2, but I am experimenting with the ATMega16 on one of your USB Audrino boards. My current prototype uses all the space you get on an experimenters version of Eagle. My final goal is to shrink the entire circuit down to a playing card. A one chip solution would be an interest alternative to cut the size, power consumption, and board complexity to more workable levels.
This chip would even be interesting at the $100 level due to the large number of components that could be remove from tilt adjusted compass solutions.
I found your posts here and am very interested in your work to use a 3-axis sensor because I built a motorized AZ-EL platform to track the sun. It works great but I keep thinking of other uses for the platform and would like to track ham radio satellites by pointing the antenna at the point the satellite rises on the horizon, track across the horizon until it sinks down into the horizon. The satellites are only available for about 10 minutes and the AZ and EL varies with each usable pass but I’ll only be interested in the few good passes in a weekend.
Right now I’m adding a home start position to my tracker but then decided to add a double cam to click HOME and the click degrees of a circle however the idea of a compass chip popped into mind and I did a google search to see of such a chip really exists and they do. So this is where I am. Hope you guys are still around to chat about interfacing the chips. My project uses a single PICAXE 20X2 for control and a 555 for long timing cycles. A dual 2 amp motor driver controls the motors. Almost everything is hand made and designed to hold 10-20 pounds of solar panels or a modest VHF/UHF antenna for satellite tracking.