820
The BMA250E is an advanced, ultra-small, triaxial, low-g acceleration sensor with digital interfaces, aiming for low-power consumer electronics applications.
Featuring 10 bit digital resolution, the BMA250E allows low-noise measurement of accelerations in 3 perpendicular axes.
A typical module
technical Information
Parameter | Technical data |
---|---|
Digital resolution | 10 bit |
Resolution (in ±2g range) |
3.9 mg |
Measurement ranges (programmable) |
±2 g, ±4 g, ±8 g, ±16 g |
Sensitivity (calibrated) | ±2 g: 256 LSB/g ±4 g: 128 LSB/g ±8 g: 64 LSB/g ±16 g: 32 LSB/g |
Zero-g offset (typ., over life-time) | ±80 mg |
Noise density (typ.) | 400 μg/√Hz |
Bandwidths (programmable) | 1000 Hz … 8 Hz |
Digital inputs/outputs | SPI & I²C, 2x digital interrupt pins |
Supply voltage (VDD) | 1.62 V … 3.6 V |
I/0 supply voltage (VDDIO) | 1.2 V … 3.6 V |
Temperature range | -40 … +85°C |
Current consumption – full operation – low-power mode |
130 μA (@ 2 kHz data rate) 6.5 μA (@ 40 Hz data rate) |
LGA package | 2 x 2 x 0.95 mm³ |
Interrupts | – Data-ready (e. g. for processor synchronization) – Any-motion (slope) detection (e. g. for wake-up) – Tap sensing (e. g. for tap-sensitive UI control) – Orientation change recognition (e. g. for portrait/landscape switching) – Flat detection (e. g. for position sensitive switching) – Low-g / high-g detection (e. g. for shock and free-fall detection) – No-motion (e.g. for power saving) |
Parts Required
Here are the parts I used
you can connect to the sensor using a standard header the classic dupont style jumper wire.
Name | Link | |
ESP32 | ||
BMA250 | ||
Connecting cables |
Connection
Wemos LOLIN32 | Module |
3.3v | Vcc |
Gnd | Gnd |
SDA – 21 | SDA |
SCL – 22 | SCL |
Code
// Distributed with a free-will license. // Use it any way you want, profit or free, provided it fits in the licenses of its associated works. // BMA250 // This code is designed to work with the BMA250_I2CS I2C Mini Module available from ControlEverything.com. // https://www.controleverything.com/content/Accelorometer?sku=BMA250_I2CS#tabs-0-product_tabset-2 #include <Wire.h> // BMA250 I2C address is 0x18(24) #define Addr 0x18 void setup() { // Initialise I2C communication as MASTER Wire.begin(); // Initialise Serial Communication, set baud rate = 9600 Serial.begin(9600); // Start I2C Transmission Wire.beginTransmission(Addr); // Select range selection register Wire.write(0x0F); // Set range +/- 2g Wire.write(0x03); // Stop I2C Transmission Wire.endTransmission(); // Start I2C Transmission Wire.beginTransmission(Addr); // Select bandwidth register Wire.write(0x10); // Set bandwidth 7.81 Hz Wire.write(0x08); // Stop I2C Transmission Wire.endTransmission(); delay(300); } void loop() { unsigned int data[0]; // Start I2C Transmission Wire.beginTransmission(Addr); // Select Data Registers (0x02 − 0x07) Wire.write(0x02); // Stop I2C Transmission Wire.endTransmission(); // Request 6 bytes Wire.requestFrom(Addr, 6); // Read the six bytes // xAccl lsb, xAccl msb, yAccl lsb, yAccl msb, zAccl lsb, zAccl msb if(Wire.available() == 6) { data[0] = Wire.read(); data[1] = Wire.read(); data[2] = Wire.read(); data[3] = Wire.read(); data[4] = Wire.read(); data[5] = Wire.read(); } delay(300); // Convert the data to 10 bits float xAccl = ((data[1] * 256.0) + (data[0] & 0xC0)) / 64; if (xAccl > 511) { xAccl -= 1024; } float yAccl = ((data[3] * 256.0) + (data[2] & 0xC0)) / 64; if (yAccl > 511) { yAccl -= 1024; } float zAccl = ((data[5] * 256.0) + (data[4] & 0xC0)) / 64; if (zAccl > 511) { zAccl -= 1024; } // Output data to the serial monitor Serial.print("Acceleration in X-Axis :"); Serial.println(xAccl); Serial.print("Acceleration in Y-Axis :"); Serial.println(yAccl); Serial.print("Acceleration in Z-Axis :"); Serial.println(zAccl) ; }