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Topic: Analog VU Meter - I2C OLED SH1106 - OLEDMeter Animation (Read 78326 times) previous topic - next topic

narkotic

This was a fun "first timer" Arduino project. I'm using these in a set of high powered class-d amplifiers.

I built it on my test bench and was able to get two displays working with two analog inputs. I tested using the audio-out from a iMac headphone port. Worked great.

Once I moved them into my amplifiers, I connected a 15v power supply (was handy) to VIN as I've read it handles between 6-20V, which powered up the unit and came to life.

I then connected the analog inputs to my speaker outputs of the amplifier. I had no music playing, but after a few seconds I heard a little zap / sizzle and one of the meters went blank. The other locked up. I shut everything down, powered back up and the ardunio (nano) was unresponsive. LED's were all on solid.

Question - did I smoke it due to the high-level speaker outputs going into A0/A1? Or by using 15v on VIN?

I think the former - and if you concur, how should I connect this thing so it doesn't blow? The amp uses balanced inputs (XLR), so I could use those instead as it's a lower level, but uncertain how since it uses pos/neg/ground. Thoughts?

Or do you think it happened due to using 15v on VIN (this is a clone nano board).

Thanks!

narkotic

Well - doing rudimentary searching has basically answered my question. Don't know why I thought that would be a good idea in the first place, but most likely it was connecting the A0/1 directly to my amplifier outputs. Lots of volts / amps swinging in both directions is bad for the analog inputs. I'll need to build a circuit to squash it down into a simple 0-5V signal and remove any negative volts as well.

Found a few cool links, here is one that really explains it all:

https://www.instructables.com/id/Arduino-Audio-Input/

In case anyone else wants to do this project...

narkotic

And it works! After building that audio-in circuit I was able to tap into my audio inputs from the positive pins on the XLR connector.

09ZX-6R

how did you get the i2c oled in fritzing?  i cant find it anywhere...even on adafruits github its not there..

stievenart

#64
May 27, 2019, 05:25 pm Last Edit: May 27, 2019, 05:26 pm by stievenart
how did you get the i2c oled in fritzing?  i cant find it anywhere...even on adafruits github its not there..
Try here:
https://github.com/adafruit/Fritzing-Library/tree/master/parts

dmaddoux

Great little project. Having fun with it! Question, just to give me a jump start, I'd like to leave this running for an extended period of time and was thinking how to use a screen saver timeout to blank the screen and use a physical button to reset the timeout and turn the screen back. I'd think if you leave it on continuously it would burn in the display.

Suggestions for a starting point or alternatives?

Thanks!

ChrisTenone

What, I need to say something else too?

dmaddoux

Not sure and do not know first hand. Just saw a mention of it happening from the author on this project:

https://dietpi.com/phpbb/viewtopic.php?t=3077


transfinite

The cheap 0.96" and 1.3" OLEDs will burn in, and slowly get dimmer over time. But they are cheap, so just keep replacement options in mind when building an enclosure for them.

jimLee

OLEDs do burn in. I burnt a couple doing the uncanny eye project. Didn't notice 'till I tried them on another project where I wanted to see some detail and color. Granted I ran the eyes for a couple years.

-jim lee
PNW Ardiuno & Maker club
1012 9Th Street, Anacortes, WA 98221 (Around the back of building)

stievenart

#70
Jul 22, 2019, 07:40 pm Last Edit: Jul 22, 2019, 08:01 pm by stievenart
Do oleds burn in?
One thing that you need to consider is the 5V I2C signal. In the past I have added a logic level converter that drops the signal to the OLEDs to 3.3v as well. Dropping the signal to 3.3V adds life to these OLEDs.

Identical to the I2C part of the article used at SparkFun: https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/all

ChrisTenone

One thing that you need to consider is the 5V I2C signal. In the past I have added a logic level converter that drops the signal to the OLEDs to 3.3v as well. Dropping the signal to 3.3V adds life to these OLEDs.

Identical to the I2C part of the article used at SparkFun: https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/all
Thanks!
What, I need to say something else too?

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