Start with the job, not the chip name: do you need tilt and balance, heading over time, barometric altitude, or only raw rotation rate? A 6-axis IMU is accelerometer + gyroscope, 9-axis adds a magnetometer, and 10DOF adds a barometer. That determines whether heading and altitude are possible at all.
| Project need | Sensor class to choose | What it gives you | Products on this page | Key limitation |
|---|---|---|---|---|
| Tilt, balancing robot, gesture sensing, basic motion | 6-axis IMU | Pitch and roll with accelerometer-assisted correction | GY-521 MPU6050 accelerometer gyroscope module, GY-BMI160 6-axis IMU with SPI/IIC | No stable compass heading; yaw still drifts |
| Stable heading, compass-aware robotics, AHRS | 9-axis IMU | Accelerometer + gyro + magnetometer for heading-aware fusion | MPU9250 9-axis IMU/AHRS module, GY-91 MPU9250 + BMP280 10-DOF module | Magnetometer performance can fall apart near motors, steel, or heavy wiring |
| Heading plus pressure or altitude | 10DOF IMU | Motion sensing, compass data, and barometric pressure on one board | GY-87 10DOF IMU with level converter, CJMCU MPU9250 + BMP280 10DOF module, GY-801 10DOF IMU sensor module | The barometer matters only if you actually need pressure or altitude; otherwise a plain IMU is simpler. If barometric sensing is the main requirement, browse pressure and altitude sensors directly |
| Angle output without writing fusion code | Serial angle module | Direct angle data over TTL Serial instead of raw IMU registers | GY-25 MPU6050 serial angle module | Easier integration, but it still does not provide absolute yaw; see how a serial angle-output module simplifies basic tilt projects |
| Simple rotational-rate sensing only | Gyro-only board | Raw angular-rate output without accel or mag | GY-50 L3G4200 3-axis digital gyro, GY-35 ENC-03RC 1-axis gyroscope | The GY-50 is a 3-axis digital gyroscope only, so it is not the right choice when tilt correction needs an accelerometer. The GY-35 is a 1-axis analog gyroscope with an MCP601 amplifier, only suits simple analog rotational sensing, and needs an ADC on the controller |
For a first accelerometer gyroscope module in robotics, the GY-521 MPU6050 board is the straightforward pick when the job is tilt, balance, or motion sensing rather than compass heading. Want direct angles over serial? The GY-25 MPU6050 module uses an MPU6050 plus onboard processing to send angle data over TTL Serial.
For heading-aware builds, MPU9250-based options add the magnetometer needed for AHRS work. If pressure matters too, the GY-87 combines MPU6050, HMC5883L, and BMP180 with 5 V-friendly logic conversion, while the GY-91 and CJMCU 10DOF board pair MPU9250 with BMP280 on compact layouts. The CJMCU board is 15x15mm. That matters in tight enclosures. The GY-801 10DOF module is another one-board route, combining L3G4200D, ADXL345, HMC5883L/MMC5883MC, and BMP180 on a 10-pin I2C module.
All MEMS rate gyros drift, and standalone gyro yaw is trustworthy for only about 10–30 seconds before accumulated error becomes a real issue. A gyroscope gives relative rotation, not absolute heading. An accelerometer can stabilize pitch and roll because gravity provides a reference, but it gives no information about rotation around the vertical axis, so a 6-axis accelerometer gyroscope module still cannot fix yaw on its own.
If your project needs compass direction or AHRS behavior, move to a 9-axis module such as the MPU9250 9-axis IMU/AHRS board, the GY-91 MPU9250 + BMP280 module, or the CJMCU MPU9250 + BMP280 board, which add the magnetometer needed for heading-aware builds. The GY-87 10DOF IMU includes HMC5883L for compass sensing and is the easier fit for 5 V systems. If you only need tilt or balancing, a 6-axis option is the better fit than paying for extra sensors you will not use; that is where an accelerometer-only and combo sensor category overlaps with this one.
If heading is the real requirement, start with using a 9-axis MPU9250 module when the project truly needs heading.
Pick by interface and output style first: raw I2C or SPI IMU, direct TTL Serial angles, or analog gyro output. That decision narrows the list faster than comparing chip names. For builds around Arduino boards, the easiest starting points are the 5 V-friendly boards and simple I2C modules.
| Product name | Sensor class | Interface/output | Voltage note | Heading capable? | Pressure/altitude included? | Distinguishing note |
|---|---|---|---|---|---|---|
| GY-521 MPU6050 3-axis accelerometer gyroscope module | 6-axis IMU | I2C | Onboard regulator for 3V or 5V operation | No | No | Configurable I2C address 0x68/0x69; includes DMP; good default mpu6050 gyroscope module path |
| GY-BMI160 Module 6DOF 6 Axis Angular Velocity | 6-axis IMU | IIC, SPI | — | No | No | Supports both IIC and SPI for buyers balancing simple wiring against faster digital access |
| MPU9250 SPI/I2C 9-axis gyro accelerator magnetometer module | 9-axis IMU/AHRS | I2C, SPI | — | Yes | No | Includes DMP, 512-byte FIFO buffer, and onboard I2C pull-up resistors |
| GY-25 MPU6050 3 axis accelerometer gyroscope module | Serial angle module | TTL Serial | — | No | No | Outputs direct angle data at 9600/115200bps in continuous or query modes |
| GY-87 10DOF IMU MPU6050 HMC5883L BMP180 sensor module | 10DOF IMU | I2C | Onboard I2C logic level converter for 5V systems | Yes | Yes | MPU6050 + HMC5883L + BMP180 on one board |
| GY-91 MPU9250+BMP280 10-DOF module | 10DOF IMU | — | — | Yes | Yes | Compact MPU9250 + BMP280 board with ±4800 uT magnetic field range |
| CJMCU 9-axis IMU MPU9250 + BMP280 atmospheric sensor | 10DOF IMU | I2C, SPI | Operates at 3.3V | Yes | Yes | 15x15mm board; BMP280 rated at ±0.12 hPa accuracy with physical measurement error of +/- 1-3cm |
| GY-801 10DOF IMU BMP180 ADXL345 HMC5883L L3G4200D sensor module | 10DOF IMU | I2C | — | Yes | Yes | 10-pin I2C module using separate L3G4200D, ADXL345, HMC5883L/MMC5883MC, and BMP180 sensors |
| GY-50 L3G4200 3-axis digital gyro module | 3-axis gyroscope sensor | Digital gyro output | 1.8V low-voltage compatible IO | No | No | 3-axis digital gyroscope only; no accelerometer or magnetometer for fusion |
| GY-35 ENC-03RC 1-axis gyroscope module | 1-axis analog gyro | Analog output | — | No | No | Uses analog output and requires an ADC on the controller |
If you want the standard raw IMU route, getting started with a standard MPU6050-based accelerometer gyroscope module is the most direct next step. If your host is a Raspberry Pi, note that the analog-output GY-35 ENC-03RC board is not Pi-direct because Raspberry Pi boards do not have analog inputs.
MPU6050 and MPU9250 are both legacy families, and both have been EOL since roughly 2019–2020. That is why pricing, availability, and authenticity vary so much across these modules.
For buyers starting fresh on 3.3 V platforms such as ESP32 boards, a newer-family part can make more sense than leaning on old 5 V-first MPU tutorials. If you are choosing a 10DOF MPU9250 combo, see working with an MPU9250 plus BMP280 combo after verifying the board is the right chip.
Raw IMUs give you more control, but they also require calibration and host-side fusion such as a complementary filter, Madgwick, Mahony, or DMP-based workflow. If the goal is simply getting pitch and roll quickly, the GY-25 MPU6050 serial angle module is the simpler branch: it provides direct angle data fusion over TTL Serial, supports 9600/115200bps, offers continuous or query output modes, and fits into a 15x11mm footprint.
There is a trade-off. Its Euler angles may influence each other at 90 degrees, which is the gimbal-lock-style behavior many buyers run into in compact tilt projects. The GY-521 MPU6050 board sits in the middle because the MPU6050 includes DMP, but it still behaves like a raw IMU purchase in most workflows. No 6-axis fused-angle option on this page provides absolute yaw heading by itself. For host-side reading on digital boards such as Raspberry Pi boards, TTL Serial, I2C, and SPI are all easier fits than analog sensors.
| Approach | Best for | Output type | Main advantage | Main limitation |
|---|---|---|---|---|
| Raw IMU such as the GY-521 MPU6050 accelerometer gyroscope or MPU9250 9-axis AHRS module | Buyers who want control over fusion, calibration, and filtering | Raw I2C/SPI sensor data | More flexible and easier to integrate into custom AHRS logic | More software work; yaw still needs a magnetometer or external reference |
| Serial angle-output module such as the GY-25 MPU6050 with serial output | Fast tilt projects and simple angle display/control | Fused Euler angles over TTL Serial | Very quick integration without writing raw IMU code | Still no absolute yaw; angle behavior gets awkward near 90° |
If that simplified route is what you need, start with using a GY-25 when you want angle values over serial instead of raw IMU data.
Because all MEMS gyros have bias or offset, and standalone gyro yaw is trustworthy for only about 10–30 seconds before drift becomes noticeable. Nonzero readings at rest are normal, startup calibration must be done while the sensor is completely still, and the bias changes with temperature.
No. A gyroscope measures turn rate, not absolute heading, and 6-axis modules such as MPU6050-based boards only provide relative rotation. Stable heading needs a magnetometer, as on MPU9250-based boards, the GY-87, or the GY-91, or another external reference such as GPS or encoders.
The GY-521 is the breakout board name, while MPU6050 is the sensor chip on it. The GY-521 board on this page adds an onboard voltage regulator and a configurable I2C address of 0x68 or 0x69.
I2C is the simplest default for most Arduino, ESP32, and Pico projects. SPI is the better fit for higher-speed reads. GY-25 sends angles over TTL Serial at 9600/115200bps, and GY-35 uses analog output that needs an ADC. That last point is what makes the GY-35 a poor fit for Raspberry Pi systems without extra hardware.
No — both MPU6050 and MPU9250 have been EOL since about 2019–2020, so current modules may come from old, recycled, or cloned stock. The practical checks are reading WHOAMI and, on “9250” boards, confirming that the AK8963 magnetometer is actually present.
No — 9-axis adds a magnetometer and 10DOF adds a barometer, but extra sensors also add calibration burden. For balancing and tilt, a 6-axis MPU6050-style board is often enough, and near motors or steel the magnetometer can become the weakest sensor on the board.
Choose GY-25 when you want tilt or angle data over TTL Serial without writing fusion code; it supports 9600/115200bps plus continuous and query modes. It still does not give absolute yaw, and Euler-angle behavior can become messy around 90 degrees.
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