Hi all, great insight on having a compass but are they accurate enough to navigate with ?

Bob is basically a metal cage full of wires which to me seems a compass nightmare. Short wires ? have it situated away from metal ? Seriously - can they help or are they more a hindrance ?

JOSH the compass you posted a photo of is serial connection, it needs transmit and received transmit is need on most compass to calibrate it and other setups,received is to get the compass reading,a nd EZB only has a one wire rs232 serial ,i think transmit so the olny one that will work are ones with true 12C connection i wish DJ wound add a received command ,good for getting info on roomba sensors and serial communication to other sensors

HAZBOT wires are not the problem as metal too,problem is magnetic fields,compass picks up magnetic fields,so anything thats a magnet ,motors,servo's fans and hard drives will give a wrong reading most data sheets on compass will tell you how much to set them apart of them,mostly 6 inches,compass are fairly accurate ,depend on the company who makes them and calibrates them

here is info from a company that makes the best one Q. Is the Compass affected by Motors, Magnets, Ferrous objects etc? A. Yes. Anything that affects the local magnetic field will affect the Compass module. Motors in particular contain strong magnets. The only solution is to mount the compass as far away from magnetic/ferrous objects as is practicable

here is info on compass on another post i reply too should not need shielded cables on the compass on a robot ,i have it 6 inches away using a pic processor and normal wires,I2C buss you can run long wires thats whats good about it can post the photo of it should be able to run long wires on I2C buss,so 2 problems it may have one is the pull up resistors on the 2 lines or a cheap compass having a week signal

So, I finaly hooked the compass up with my EZ-b. It seems to be working, but after 5 seconds I lose connection and ARC sort of stops working...

Any ideas on whats happening?

might be a reset problem,from noise,did you restart it again in a few weeks mmaybe more looking to do some testing on why the wires need to be short on only SURE compass its very strange,you get long run wire from I2C buss,can post my seeker robot design that i have a I2C compass about 2 feet away from the control board and working fine but i am using CMPS-03,also DAVES SHINSEL SEEKER robot has it too and there where i made mine from with some changes SO thinking the signal is very week form a china made compass or the pull up resistors and some how noises are causing a reset on EZB

also BRUDEL0 do you have a O-SCOPE,best tool for checking noise in the system

Talking to brother who knows about this sort of thing the edges produced by the MCU (or EZ-B in this case) can be too fast for the I2C device so if you put a 100 ohm resistor in the 2 signal lines in series with them. This will take the edge off so to speak as it acts like a small low pass filter with the capacitance of the input stage of the I2C device.

It may not solve the problem of course and I can't try it as my compass module hasn't arrived yet. But its a known solution to intergrating I2C devices with an MCU controller

they may work too,i seen that on another forum but it will also divide the voltage down,since there is a pull up of 10 k and in series adding 100 ohm thats a voltage divider the EZB uses near the same processor thats on my SEEKER robot that uses a CMPS03 that does have that problem at all and using it at 24 inches away from the board

i think on BUDEL0 case is different,seem a noise problem ,not a compass problem ,since others have it working BUDEL0 he is a try ,remove compass and see if you are having same problem ,if you still do ,then not the compass, ,can be noise on the lins (hard to find without a scope) or drawaing to much current from other stuff or on the digital or I2C lines what do you have hook up and where

@robotmaker

1. No I don't have a scope.

2. My robot works fine when I don't have the compass connected. When I connect the compass while its connected to my pc it stops working again...

3. I have connected to my EZ-B:

   • 2x 20A ESC
   • 7x servo
   • Synapse RF100 module
   • 2x 7.2V 20C 4000mah lipo battery (soon to be 3x)
   • 1x Ping sensor
   • 1x ADC voltage sensor

I think I covered it all.

@winstn60 I will try it. I hope it works, because I'm working on something special for navigation ^^.

ok,so it is the compass.first do you have pull up resistors on each line,very important second adding that 100ohms might help like winstn60 said