Can't detect I2C displays with Arduino Nano

Question

All cables tested and work:

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

I'm using an Arduino Nano board and an I²C display - I've tried everything to get it to work and I'm now convinced it's 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).

This is the code I used, i2c_scanner, and this output:

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?

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

score 5 · Answer 1 · answered Jun 18 '15 at 16:18

5

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

answered Jun 18 '15 at 16:18

Anonymous Penguin

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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 04:53

score 2 · Answer 2 · edited Jul 08 '18 at 08:48

2

Check the solder jumper on the display. Note the example code is for one address, but two 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.

edited Jul 08 '18 at 08:48

Greenonline

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answered Jun 20 '15 at 02:46

johnm

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score -1 · Answer 3 · edited Jul 07 '18 at 18:06

-1

I had the same problem, with a lot of time lost, I tried to give current from another source, (an Arduino one) is all works, I think these Nano clones have some bugs on output voltages, to be checked. Anyway, so it worked.

edited Jul 07 '18 at 18:06

Greenonline

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answered Jul 07 '18 at 16:50

Format tatoio Al-Formattatoio

1

I am not sure if this is an answer, or a comment. – Greenonline Jul 07 '18 at 18:06
1

@Greenonline You could flag it as "not an answer", but it will probably be declined and you'll be told the reason is - flags should not be used to indicate technical inaccuracies, or an altogether wrong answer. In my opinion, if a person is going to answer a 3 year old question that the OP has abandoned, it better be a good answer. This answer does not address any of the issues that are clearly visible in the OP's picture, not does it point out the incorrect wiring. You could try flagging it as "very low quality" and see what happens. – VE7JRO Jul 07 '18 at 18:47
1

@VE7JRO - Good point, I had flagged it as "Not an answer" but I have retracted it, for the reasons you state, although it would serve better as a comment. I'll leave it be, even though the obvious answer is that of Anonymous Penguin, as I don't want to earn any more declined flags :-). Also, I am not sure why there are two answers from the same user. – Greenonline Jul 07 '18 at 18:52

Can't detect I2C displays with Arduino Nano

3 Answers3