Piezo Accel Click

How does it work?

Piezo Accel Click, as its foundation, uses the 820M1-0025, a piezoelectric accelerometer designed for embedded condition monitoring and preventive maintenance applications from TE Connectivity. The 820M1-0025 accelerometer is available in the range of ±25g and features a flat frequency response up to >15kHz. Featuring stable piezoceramic crystals in shear mode sealed in a fully hermetic LCC package, the accelerometer incorporates an amplified ±1.25V output with optimum measurement resolution. This Click board™ is suitable for machine health monitoring and has superior resolution, dynamic range, and bandwidth to MEMS devices.

The piezoelectric technology incorporated in the 820M1-0025 accelerometer has a proven track record for offering the reliable and long-term stable output required for condition monitoring applications. This output signal can be processed in two ways, as an analog value or converted to a digital using the LTC1864, a successive approximation A/D converter with a 16-bit resolution from Analog Devices. This ADC includes a sample-and-hold feature and has a differential analog input with an adjustable reference pin used as the reference input resulting in accuracy and stability the 4.096V reference voltage level provided by the MCP1541 from Microchip.

Piezo Accel Click communicates with MCU using the 3-Wire SPI serial interface through an earlier mentioned AD converter, the LTC1864. The 5V logic level provides a needed reference voltage for one side of the TXB0106, a 6-bit bidirectional level shifting, and a voltage translator with automatic direction sensing from Texas Instruments. On another side of the level shifter, the reference voltage is taken from the 3.3V pin from the mikroBUS™.

In addition to the AD converter, the output of the 820M1-0025 can be also sent directly to an analog pin of the mikroBUS ™ socket labeled as AN. An output signal processing can be performed by placing an onboard SMD jumper labeled as AN SEL to an appropriate position marked as AN and ADC.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to properly use the SPI communication lines. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on Piezo Accel Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Analog Signal	AN	1	AN	PWM	16	NC
	NC	2	RST	INT	15	NC
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Piezo Accel Click electrical specifications

Software Support

We provide a library for the Piezo Accel Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Library Description

This library contains API for Piezo Accel Click driver.

Key functions:

• piezoaccel_cfg_setup – Config Object Initialization function.
• piezoaccel_init – Initialization function.
• piezoaccel_default_cfg – Click Default Configuration function.

Examples description

This application demonstrates the performance of Piezo Accel Click board™.

void application_task ( void ) {
    float read_val;
    
    read_val = piezoaccel_g_unit_read( &piezoaccel, &setup_cfg_data );
    log_printf( &logger, "%.2f,%.2frn", read_val, time_var );
    time_var += time_incr;
    Delay_ms( time_incr );
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on mikroE github account.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.PiezoAccel

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.