Raspberry Pi i2c Read/Write Error

Question

Like many people, I've had a Pi for a while but never really done anything with it. I've finally got round to hooking up an MPU6050 IMU to play around with. It uses i2c for communication so I followed the guide by Adafruit regarding enabling i2c shown here Adafruit i2c .

I then hooked up the MPU6050 to the i2c bus, and using i2cdetect -y 1 I was able to see a device at 0x68.

However, when trying to read or write from the device I got a permission denied error, so I followed this post to solve that problem /dev/i2c-x permission . It told me to modify /lib/udev/rules.d/60-i2c-tools.rules with

KERNEL=="i2c-0"     , GROUP="i2c", MODE="0660"
KERNEL=="i2c-[1-9]*", GROUP="i2c", MODE="0666"

This worked, but then when actually trying to read or write using C++, I get "Input/output error". Similarly, using smbus in Python I get [Errno 5] Input/output error When connected to an Arduino I can get this device to work perfectly.

I've exhausted every forum post I can find. Hopefully I've just done something stupid. Anyone got any ideas?

Original model B RPi running Raspbian, if that's of any help.

Cheers

Answer 1

In normal cases you don't really need to change the /lib/udev/rules.d/60-i2c-tools.rules file, so I would recommend resinstalling raspbian.

Connect the MPU6050 to the correct pins:

Then download an official Adafruit library:

• C++
• Python

Check if the Raspberry Pi's I2C is enabled with $ sudo raspi-config and make sure the I2C address is correct, besides checking it with $ i2cdetect -y 1 , like this:

try:
  bus = Adafruit_I2C(address=0)
  print("Default I2C bus is accessible")
except:
  print("Error accessing default I2C bus")

mcp = None

for i in range(0x00, 0x28):
    try:
        mcp = Adafruit_MCP230XX(address=i, num_gpios=16)
        break
    except:
        pass