Geeetech

Hello!

Yesterday I received the magnetometer, I tried but NOT working. I have an Arduino Mega. I've connected to GND and Vcc+3.3v, sda (pin20 Arduino), scl (pin21 Arduino), with pull-up resistors of 10Khom. I have also used the libraries HMC5883L, HMC58X3L and HMC and some examples as
www.sparkfun.com/tutorials/301, without success.

Seeking information Google, I found a sketch for Arduino that lets you scan the I2C bus. If I connect only HMC5883L not find anything, but if I connect another device to I2C, yes it is, for instance with RTC plus Sd shield gives me the direction 80.
http://dsscircuits.com/articles/the-mys ... 5883l.html

Another Sketch also execute a scanner which is specific for a HMC5883L, with the same result.
Any suggestions please? Thanks and best regards!

Hi there;
If only using one I2C device, the pull-up resistors are normally not required, Arduino has them built-in. However if you are running a string of devices, use two 10 kilo ohm resistors. Try to remove pull-up resistors and tell us if it works well.

Thanks

Hello,
I rewiring without the pull-up resistors, only Mega HMC5883L with 3.3v + gnd, SDA (PIN20) + SCL (Pin21), as in the example of www.sparkfun.com, but does not work. ScanI2C also still does not see any device in I2c Bus
I made another test, something odd, but I get the following result:
If I connect a Shield with I2C bus in SDA and SCL socket but without power, the Sketch ScanI2C hangs and does not begin to scan up to give power to the Shield, then find the device at address 80. If I do the same with the HMC5883L, the ScanI2C always work and I see 00 in all directions. In this case it does not matter HMC5883L has power or not. It's as if there is any problem with the I2C port magnetometer, right?

Thanks for your help ...

..Forget to remove the pull-ups. 5k +- is OK (internal ones do NOT do the job)
You are not the ony one with a problem. Here is the short version of my story:

I have bought 2 pcs HMC5883L magnetometers.
One works fine, the other is DOA.
I have done all I possibly can do (exept altering the board) to deterime that I have a defective board.
Visual (under microscope) inspection. Verified all connection lines point to point. It looks OK.
I do not have the equipment needed to resolder the board, nor to test the onboard, unmarked, capasitors.
Now I just need to know how we can make this right?

-----------------------
Already done:
Contact outside this forum. (direct copy of earlier messages):
1:
From: knut2307 To: ge-th2009 - Sent Date: 2012-03-29 16小時02分45秒
I have just added connection pins to the two compass modules.
One of then works fine, but the second one will not 'come to life'.
By first glance ,the circuit board seems to have a defect. I will investigate it further under a microscope and try to resolve the problem.
If there actually is a defect, I will notify you again...
THIS message for you information only. (I'll try to resolve this myself so i can get the board working)
Yours. 'my name' , electronics engeneer
------- Answer:
Dear Friend,
Thanks for your mail,
No problem,if there is any problem,just feel free to contact us,we'll do our best to help you out.
If you also have any problems,please enter into this forum to raise your questions on the "Problem Solving".
http://www.geeetech.com/forum/
Our technicians will do their best to help you to solve this problem..
If you have any problem,just feel free to contact us,we'll do whatever we can to help you.
Best Regards
2: From: knut2307 To: ge-th2009 Sent Date: 2012-03-30 06小時11分03秒
Hi again.
I have now examined the board under a microscope, and I can find nothing wrong.
..no broken lines, no short circuits and the capasitors seems to be connected OK.
all signal lines are OK from microcontroller to the magnetometer-chip.
(I cannot tell if the chip is connected properly to the PCB (because the connectors are hidden under this SM-chip)
I have tried 'ping' to all I2C-adresses, but the chip will not answer!
One of the boards answers OK to address 01E, but the other do not (which it should))
Summary:
I find the board not working (DOA) and I want to return it for a new one.
Now, I need to know if I shall remove the connector pins I soldered on ?
...and I need an shipping address where to send the faulty card.
...yours.. 'ny name', teacher of technology , Narvik, Norway
------- Answer:
Dear Friend,
Thanks for your mail,
Do you tell your problem to our technicians on our forum?
http://www.geeetech.com/forum/
Did they give you some guidence on how to test if it's defective?
Waiting for your reply,hope to help you to solve this problem.
Best Regards

Hi !
Well, finally seems to confirm that the module is defective and DOA is accepted. Today I received an email shortly confirming that I will receive another HMC5883L. When I receive it, write a post on this forum.
KNUT Thanks for your help (I received yesterday your comments by mail).
Greetings!

Hi there!

Today I received an email from Paypal telling me that they have given me back the purchase money. Apparently, they did not make the shipment of the item again, as they said...that's all folks!
Thanks anyway.

OK, Welcom to post your project at any time. let's share you experiment together.
Thanks,