INA219 not working/recognized

[Martius108]

Hello,

I built up everything on a breadboard and run all components on 3.3 V. The display shows the initial values as long as only the ATtiny85 is attached to it. As soon as I connect the INA219 the display shows nothing. I have the pins A0 and A1 connected to ground so I had a look into your sketch and found out that you set the I2C address to 0x80, but in my case it should be 0x40, right? But that wasn’t the solution unfortunately. Any idea what else could be the issue here?

When I wrote my first issue here I had a ready made INA219 module attached without any problem. Everything was running on 5V. But now I use the INA chip just with the shunt and a 100 nF capacitor attached.

[wagiminator]

The firmware uses the address with the write bit, so 0x80 = (0x40 << 1) | 0 is correct. You must have made something wrong in the wiring, maybe on the I2C bus because the OLED stopped to work.

[Martius108]

Thank you. The wiring was ok, but under the magnifying glass I found a little shortcut at the INA chip. It’s not so easy to hand solder a SOT-23 :)

[wagiminator]

You're right, I also have my difficulties with that!