Monochrome 128x32 I2C OLED won't turn on (solved)

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ineffective dosage
 
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Monochrome 128x32 I2C OLED won't turn on (solved)

Post by ineffective dosage »

I purchased the 128x32 I2C OLED (http://www.adafruit.com/products/931) and wired it up as shown at http://learn.adafruit.com/monochrome-ol ... 2c-display with the exception that I'm using a 3.3V Arduino Pro Mini, so Vin is 3.3V (not 5V like in the example) but that page says this is OK to do. 2.2k pullups on the I2C lines.

I successfully installed the libraries Adafruit_SSD1306 and Adafruit_GFX (though I had to rename the libraries - replace '-' with underscores because '-' is an illegal character for library names in Windows apparently).

Then I fired up the example code for 128x32 i2c (changing a #define in the Adafruit_SSD1306.h file to reflext 32 height, not 64 which was the default).

I compiled and uploaded A-OK but the display remains dark no matter what I do.

Is there some way I can test the display at some low basic level, just to see if it winks or something? During power up and resetting (and of course during the example code) the display remains totally dark.

Any clues what I'm doing wrong?
Last edited by ineffective dosage on Fri Jan 24, 2014 8:31 pm, edited 1 time in total.

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by adafruit_support_rick »

Please post clear, focused pictures showing your soldering and connections.

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by ineffective dosage »

Sure thing. Let me know if you need any additional detail - it's just breadboarded at the moment so it can be hard to see which wire goes where because of perspective.

Power is not currently connected during these photos.

Overview. Resistors are 2.2k I2C pullups:
Image

Closeup temp connections to A4/A5 for I2C
Image

Closeup temp connections to I2C display - 3.3V pin is unconnected, Vin is tied to 3.3V supply (but powered down atm). Reset to digital 4 as per test code.
Image

Overview, different angle:
Image

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by adafruit_support_rick »

First thing is to improve the solder connections on the OLED. Those look like cold joints - the solder hasn't flowed over the pads and up the pins. Your solder connections should look like this:
Image
If that doesn't help, try it without the pullups, and try some different breadboard sockets. This seems like a connections problem someplace - if it's not the solders, then it must be in the wiring.

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by ineffective dosage »

Will do. Is there any kind of "flash" or "blink" I can expect to see on the OLED when powering it up or resetting, etc? That would help me troubleshoot as well. As it stand there is no indication whatsoever.

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by adafruit_support_rick »

Nope - I don't recall seeing any power-on blinks.

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Re: Monochrome 128x32 I2C OLED won't turn on

Post by ineffective dosage »

Success, Rick - thanks! Turns out I had a dead spot in my go-to always-reliable-until-this-moment breadboard. Who knows how long before I'd have gotten around to that without your poke in the right direction. :D

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Re: Monochrome 128x32 I2C OLED won't turn on (solved)

Post by adafruit_support_rick »

We see breadboard stuff like that all the time.

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