Electrical – How to debug an I2C Sensor conntected to a raspberry pi with a multimeter

debuggingi2cmultimeterraspberry pisensor

I am a noob in eletronics, so I need some help. I want to debug an i2c sensor with a digital multimeter such like this:enter image description here

And I have a setting like in the picture below where tmp102 is my i2c sensor on a breakout board, red is 3V, black is ground, green is SCL and yellow is SDA. Here it is a anduino, but I am using a raspberry pi, but the connections are the same.
enter image description here

My question: how can I use this multimeter with what configuration (position of the pointer and cable plugin ports) on the above setting to debug it? Where put the pins on the setting? Where can I measure something with this multimeter and what values should I expect?

THanks in advance for some help. I couldn't find such a easy and simple guide by using a lot of search engines. I only want to know in a simple an practical way what is the right way to use a multimeter to verify that an i2c sensor works right/ is right connected from the electrical point of view…

Best Answer

How you connect your measuring device depends on what you want to verify.

With a multimeter you can check pullup functionality and SCL frequency.

For pull up functionality you need to set your multimeter to DC voltage sensing, connect the black probe to gnd, and the red to SCL and SDA, alternatively. Both should read VDD, in your case 3 V.

To measure SCL frequency set your multimeter to Hz, connect the negative probe to GND and the positive to SCL. Now load and run a script that continuosly tries to access the temperature sensor: the frequency you will read on the multimeter is (to some extent) close to SCL frequency.

There are not other tests you can perform with a multimeter, if we exclude basic connectivity checks.