Lesson 5 of 7

I²C: find the MPU-6050

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#include <Wire.h> // Scan the I2C bus, then read the MPU-6050's WHO_AM_I register const int IMU = 0x68; void setup() { Serial.begin(115200); Wire.begin(); // SDA and SCL: the same pins as A4 and A5 Serial.println("Scanning I2C..."); int found = 0; for (int address = 1; address < 127; address++) { Wire.beginTransmission(address); if (Wire.endTransmission() == 0) { Serial.print("Found a device at 0x"); Serial.println(address, HEX); found++; } } Serial.print("Devices found: "); Serial.println(found); } void loop() { Wire.beginTransmission(IMU); Wire.write(0x75); // register 0x75 holds the chip's ID Wire.endTransmission(false); Wire.requestFrom(IMU, 1); if (Wire.available()) { Serial.print("WHO_AM_I = 0x"); Serial.println(Wire.read(), HEX); } else { Serial.println("No answer"); } delay(1000); }

Stopped · Your code isn't running yet. Until you press Run, the board runs the program already on it.

Nothing printed yet. Press Run.

Scan the I²C bus for devices, then ask an MPU-6050 motion sensor who it is. I²C is two wires shared by many chips, each with its own address.

An MPU-6050 on the bus
127 addresses on one pair of wires
On the WiFi, a Qwiic sensor goes on Wire1, not Wire

Pin	Connects to	What it does
`SDA`	The module's SDA	I²C data, the same pin as A4.
`SCL`	The module's SCL	I²C clock, the same pin as A5.
`5V`	The module's VCC	Its regulator makes 3.3 V for the chip.
`GND`	The module's GND	The shared ground.

Wire it in

Sensors and actuators this board drives, with the real connections.

MPU-6050 IMUSupply 5 V
VCC to 5V, GND to GND, SDA to SDA, SCL to SCL. It answers at 0x68 (0x69 with AD0 high). The breakout's own pull-up resistors matter here: the R4 has none fitted.
Part pin Board pin
VCC 5VWire colour red
GND GNDWire colour black
SDA SDAWire colour blue
SCL SCLWire colour yellow
Careful
Use a breakout with a regulator on it (the common GY-521 has one); the bare chip is 3.3 V only.

Part pin	Board pin
VCC	5VWire colour red
GND	GNDWire colour black
SDA	SDAWire colour blue
SCL	SCLWire colour yellow

All 6 parts on the Arduino UNO R4 page

I²C: find the MPU-6050

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in

I²C: find the MPU-6050

Try it yourself

Serial monitor

Checks

Break it

Inputs

Parameters

Wire it in