some help with i2C ina219&Oled display &RTC1307

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1

Hello ,

I’m having some problem whit theI2CD communication.

I have connected

3 ina219 (address 0x40,0x41,0x42)

1 oled (0x3d)

1 RTC( 0x68)

to my arduino (cables lest then 20 cm), didn’t use any external pullups

all devices are connected to 5V on the Arduino

when I run the scanner code in the Arduino - I can see al 4 of them without any problem

I wrote a simple code that read all ina and the rtc , then display in the oled . work just fine

now I wan to do the same thing in pythin code using Raspberry pi 4.

but when I connect the same circuit to the PI - it dosen’t work (I have enable the i2c in the setting)

when I connect only the OLED or the ina219 - it’s working for sometime , then stop

I have read and saw that the pi is work only wiht 3.3V

I guess this is the problem ?

Anyone can confirm that ?

also what do I need to do to make it work on the pi ?

the devcies are working on 5V , so SDA&SCL are 5V also , no ?

do I need to use one of this?

https://www.sparkfun.com/products/12009

will this fix my problem?

Thanks ,

2

The current sensor and the OLED should work on 3.3V because that is supposed to be their regular voltage level. However, your RTC may not since it’s supposed to be 5V. If your RTC is an open-drain system then you can pull the voltage up to 3.3V and power with 5V. Do you have a link for the RTC?

3

https://www.sparkfun.com/products/12708

if what you say is correct ,

I have try to run it without the RTC1307

connect them to 3.3V (from the pi)

and its not working , in the sacn I don’t see nothing

disconnect it , connect the circuit to the arduino (using 5V) - and all devcies are working

4

Do you have other links for your other modules as well so I can make sure I didn’t look up the wrong parts?/

Can you include any images of your setup or schematic?

5

the other modules are not from sparkfun - is this OK?

6

I’ve run into this with the DS1307 before, they will not work on 3.3 volts and require 5 volt power to function.

Now I don’t know for sure if SDA and SCL will work at 3.3 volts, (haven’t tried) but it would be worth your while to remove any pullup from your board that pull both lines up to 5V and let the pullups on your other I2C devices do that work.

That might be enough to make the DS1307 work with your setup (You will need to try) but if it doesn’t you will need some sort of logic level conversion between the 3.3 and 5 volt portions of your I2C bus.

The [PCA9306 should do the trick and the [bi-directional logic level converter might also work provided the impedance on your I2C bus isn’t too low.](https://www.sparkfun.com/products/12009)](https://www.sparkfun.com/products/15439)

7

great bought it , hope it will arriave soon so I can check

Thanks !