I been trying to interface MPU6050 and HMC5883 with an Arduino Pro Mini/Nano. I²C scanner works just fine and identifies the device with no issues. I let the I²C scanner run like for 5 minutes and I see fumes coming out of the chips and sometimes the Arduino itself is burnt. I tried pull up resistors 2.2k, 7k without any luck. Has anyone got any inputs to this issue. Really frustrating to spend a weekend on this :(

To rule out the possibility of 5V supply causing the burn out I tried 3.3V from Nano and made promini 3.3V from 5V. Please see the pictures below.

Arduino Nano 3.3v was used to power up the I²C.

Arduino Nano Circuit.

Pro Mini Circuit.

Pro Mini jumper was desoldered from 5V to 3.3V to see if the I²C chips are saved from being burnt. In both these setup voltage accross the I²C chip was measured and it was 3.3V.

Still no luck!

If you guys are to make the same circuit how would you do it and where would you get the components from? I must be doing something wrong and hope we together can figure it out.

Components are bought from eBay and the links are here. GY521 = goo.gl/Y4aDph HMC5883 = goo.gl/DfrC9l
Arduino Nano = goo.gl/CaAykI PROMINI = goo.gl/79PVOM

This is some background of why this issue resolution is so important to me: Just give you a backgroud of why I am doing this: I am building a quadcopter myself. Infact built one using GY80, but the module was expensive also it eventually got burnt out for the same reason mentioned above. Here is the first successful test flight of my first quadcopter goo.gl/rn6xWG (add https:// since I am rookie there is limitation on how many links I can post). If I can make the same thing work using GY521 and HMC5883 it would be awesome and cheaper.

Update on 08/11 @12:45 PM CST I think it is because of the Pro Mini, I²C chips are getting fried. When using Nano, I think it is because of the voltage level difference between the SDA/SCL lines causing the problem. With Pro Mini tripped for 3.3V, I was not able to see any serial data from the chip too. To end all these I placed an order for 3.3V 8 MHz Pro Mini from amazon goo.gl/FjgTGj Let see how that goes.

  • 1
    burnt for no reason - chips don't burn for "no reason". There is a reason, you just haven't found it yet.
    – Nick Gammon
    Aug 10, 2015 at 6:21
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    Arduino Nano/PROMINI, A4->SDA, A5->SCL, VCC to VCC, GND -> GND. Simple wiring on a bread board. I will send the picture later once i set up the circuit again.
    – Mohamed
    Aug 10, 2015 at 15:05
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    Here is the diagram db.tt/4ocbNOYW. Without pullup resistors and trying the GY521 or HMC5883 alone is burning the chip. GY521 or HMC5883 I am using is a 3-5V variant should have been working just fine. GY521 = goo.gl/Y4aDph HMC5883 = goo.gl/DfrC9l Arduino Nano = goo.gl/CaAykI PROMINI = goo.gl/79PVOM – Mohamed 2 mins ago edit
    – Mohamed
    Aug 10, 2015 at 15:40
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    so If the promini is made 3.3v 8MHz from the 5V 16MHz, should it just work fine? or if I power the I2C devices from the 3.3v pin of the the Nano? I will try both ways and let you know. @Gerben I am reverting the pullup resistor changes from the wire library for now then.
    – Mohamed
    Aug 10, 2015 at 19:05
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    I checked that it was 3.3V. No chip was getting hot like real hot but i can see fumes at times from the HMC5883 or GY521 for that matter. This last test i did no fumes happened but it fried the chips. If you masters are to make such a circuit how would you do it and where would you get the components from?
    – Mohamed
    Aug 11, 2015 at 2:25

1 Answer 1


enter image description hereFixed the issue with a dedicated 3.3V power supply. I2C scanner is running for 30 minutes with no issues so far.

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