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enter image description here

SCL - A5 SDA - A4 VCC - 5v GND - GND

All cables tested and work ..

Im using an arduino nano board and an I2C display - Ive tried everything to get it to work and im now convinced its a hardware fault. Using the Arduino I2C address scanner, it is unable to find a device, even though it is wired correctly(I've checked multiple times)

http://playground.arduino.cc/Main/I2cScanner <--- Thats the code I used

Scanning... No I2C devices found

Scanning... No I2C devices found

Scanning... No I2C devices found

Scanning... No I2C devices found

Scanning... No I2C devices found

Scanning... No I2C devices found

Scanning... No I2C devices found

Is all I get - any suggestions? (Or is my board output fried?)

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To use i2c you normally need pullup resistors on sda and scl, except if the slave device has some. Add 2 pullup resistors to your circuit (you can use 10k, that should be ok). – jfpoilpret Jun 17 '15 at 17:20
    
You need to understand how I2C works first. – Chetan Bhargava Jun 19 '15 at 5:37
up vote 1 down vote

You seem to have two issues here:

  • As already pointed out, you have the white wire connected to the wrong pin on the Arduino
  • Also, you need to solder the headers on the Arduino. There is no solder on the pins, which means that there is no connection. You need to solder those headers on; it looks like you just set the Arduino on top, which won't work with headers
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Agreed absolutely. Shoving the header pins into the holes simply won't work. You must solder them. – Nick Gammon♦ Jul 20 '15 at 4:53
up vote 0 down vote

Try adding some pull-up resistors to the I2C lines, that might help a bit. Some 2k2 - 4k7 ones should probably do the trick :)

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That white wire is connected to VIN instead of GND on your Arduino board. You need to move the wire over one slot in the breadboard.

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Check the solder jumper on the display. Note the example code is for one address, but 2 addresses are supported. try the other address in code, or solder the lcd address pads to select the address to match the code. I had the same problem, the printed address on the lcd solder pads is just the last address bits that make the difference..

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