Hi I have a weird issue I’ve tested this setup on arduino nano consisting of (ssd1306,ina219) When I change to esp31 dev 1 kit the ina219 will not show up. I used i2c scanner and it on sees the ssd1306. The ssd1306 does indeed work I can upload and change fonts. I can also run examples on ssd1306. But I can’t run any ina219 they all fail 
@Chuck60, your topic was moved to a more suitable location on the forum.
Please provide a proper wiring diagram / schematic; a photo (sized to around 300kB or less) of a handdrawn one is OK.
I have yet to add the fly back diode in5817 on fan circuit from another post. It will be powered by two separate buck converters
I have made a few changes as per another member I will add a 1k to PWM change 1k on gate to 10k add a fly back diode to fan. Reduce the the Cap on fan from 470uf to 220uf lastly the .05 resistor is 1% 3w. But I removed it from the equation to simplify the problem solving
Try with external pullups of 4.7K to 3v on D21,D22.
Thanks you cattle dog I tried 4.7k on 3.3v nothing 
Try posting the code as you wrote it.
Remove the DS1306 and see if you can get the ina219 to show up.
In your drawing, both the modules are powered with 3.3V.
In the photo the modules seems to be powered with VIN. You need to power both of them with 3.3V.
Do you have a multimeter ? Check the wires and the voltages.
SDA and SCL should not be near each other. The I2C bus can not handle crosstalk. Can you pull those wires apart ?
Did you know that a OLED display disturbs the I2C bus for others ? Removing the OLED as @noweare wrote is a good test.
Unrelated, but the NTC/resistor should be powered from the 3.3volt pin.
The ESP32 is a 3.3volt processor.
Powering the NTC from 5volt could be dangerous to the pin, and you will have temp instability.
Leo..
I’ve tried the ina219 on its own with just the sample code several times. In 5v and 3.3v nothing
I will send it as soon as I’m at my computer
I have powered them on both 3.3v and 5v
The voltages are both 3.3v, vin is 5v
Ah that could be it crosstalk 
but honestly the ina219 is not working even connected to esp32 on its own
I tested it on its own I guess it’s either bad ina219 or a issue with esp
Ok I will power it with 3.3v
How many INA219 modules do you have ? Are they all the same modules ? Where did you buy them. Perhaps there is a large number of INA219 modules out there which do not work. It happens.
Can you check the wiring up to the INA219 chip itself with a multimeter ? Also check all the voltages when it is connected.
Is there something that is the same for every test ? For example a wire, a breadboard, the power supply or something else ? Can you try to change everything ?
You could buy a different INA219 module form a different seller. Use an other computer, and other USB cable, an other power supply, an other Arduino board, an other breadboard, other wires.
If you don't have a reliable multimeter, that should be the first thing you need to buy.
Thank you for your response I have purchased 2 ina219 from another seller and they work all is good now
Thanks for letting us know 
So there is a whole series of bad INA219 modules 
Then we might see more questions about it on this forum.
YW I thought I was the only unfortunate. Mine was sold under the name hiletgo. But they sent me replacements that do in fact work
This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.