user85027: I have a NodeMCU esp32-s board and I'm trying to connect My 16x2 lcd with PCF8574T I2C bus to the esp32 , the problem is that the lcd doesn't show anything and the WireScan sketch can't recognize the lcd too,but when I use arduion uno ,it's recognized and work perfectly ,I hope somebody can help me,the schematic for the connection is :

the schematic for the connection of the lcd with the bus is below with the bus module part number :

user14095: You can run the PCF8574 on 5V and the EXP on 3V3 just be sure the I2C is pulled up to the 3V3 and NOT the 5V. I do this a lot and have never had a problem. The reason it works is the bus is driven by open collector/drain drivers which do not source any voltage.

85027: <p>I have a NodeMCU esp32-s board and I'm trying to connect My 16x2 lcd with PCF8574T I2C bus to the esp32 , the problem is that the lcd doesn't show anything and the WireScan sketch can't recognize the lcd too,but when I use arduion uno ,it's recognized and work perfectly ,I hope somebody can help me,the schematic for the connection is :
<a href="https://i.stack.imgur.com/FjBC1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FjBC1.png" alt="enter image description here" /></a></p>
<p>the schematic for the connection of the lcd with the bus is below with the bus module part number <a href="https://i.stack.imgur.com/0NXcS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0NXcS.png" alt="enter image description here" /></a>:</p>
 14095: <p>You can run the PCF8574 on 5V and the EXP on 3V3 just be sure the I2C is pulled up to the 3V3 and NOT the 5V. I do this a lot and have never had a problem. The reason it works is the bus is driven by open collector/drain drivers which do not source any voltage.</p>
