compass Module 3-Axis HMC5883L
Fatfenders
Posts: 39
in BASIC Stamp
Several years ago I built a street rod ('36 Chevy Coupe) and installed a Pioneer DVD player and placed the control unit between the sun visors as shown in the image below. A coupla years ago I deleted the DVD player and installed a modern 2-din radio(quantum leap in technology). Problem is I still have the now non-functional Pioneer control unit looking at me every time I get in it. I don't like non-functional anything in my old car so I decided to see if I could cobble in a digital compass and maybe even an altimeter(just for fun). I found a (4 year old) DIY video (HackaweekTV) that shows how to configure the Parallax compass. (I could cobble in the LCD where the DVD control now resides, no problem)
Unrelated, 3-4 years ago I decided to play around with the Parallax robot. Sorta learned how to program it (spent 30+ years as a mainframe assembler programmer) and more or less got comfortable with the technology. Which brings me to a 3 questions:
Hackaweek suggests that you move the compass unit several inches away from the board but doesn't really explain more than that. How necessary is that?
When I played around with the robot I purchased the Basic Board of education. Hackaweek uses a Propeller BOE. Can I use the Basic BOE with the compass module?
What kind of an effort would it be to combine both the compass and altitude module and display them on the same LCD?
Unrelated, 3-4 years ago I decided to play around with the Parallax robot. Sorta learned how to program it (spent 30+ years as a mainframe assembler programmer) and more or less got comfortable with the technology. Which brings me to a 3 questions:
Hackaweek suggests that you move the compass unit several inches away from the board but doesn't really explain more than that. How necessary is that?
When I played around with the robot I purchased the Basic Board of education. Hackaweek uses a Propeller BOE. Can I use the Basic BOE with the compass module?
What kind of an effort would it be to combine both the compass and altitude module and display them on the same LCD?
Comments
The main reason to move the sensor away from the board is to add to the distance between the sensor and the servos. Motors induce magnetic fields which can be much stronger than the Earth's magnetic field. The board itself shouldn't cause much interference unless there are some inductors used in a switching voltage regulator.
I'm not sure about this. To calculate the heading from the raw sensor output requires a bit of trig. I don't know how well the Basic Stamp performs trig calculations.
As long as you can read the individual sensors, I don't see any problem with using both sensors with a single LCD.
Unless someone else chimes in to suggest how to do this with a Basic Stamp, you might want to consider getting a Propeller Project Board. IMO, the Propeller Project Board is the best bang for the buck of the boards Parallax sells.
Other good options for Propeller boards are the Propeller Activity Board, the QuickStart Board and the Propeller Mini. If you get a Propeller Mini (which is nice and small), you'll also need a Prop Plug to program it.
I have links to a bunch of Propeller tutorials in my "index" (see signature or this link).
Here's a project I did with the Propeller an a HMC5883L sensor. I ran into trouble with the magnetic fields from the servos. The contraption worked much better once I used a three inch rod to elevate the sensor (though I didn't ever make a video of the improved version).
These magnetometers generally require a bit of calibration in order to provide accurate headings. As long as your car is going to remain relatively level, you probably don't need to worry about tilt compensation which can be a big deal if the sensor isn't going to remain level.