Measure the angle direction of a magnetic field from a magnet with HMC1501 and PIC32MZ2048EFH100
Make previously unattainable levels of precision a reality
Published Sep 15, 2023
Click board™
Magnetic linear click
Dev. board
Flip&Click PIC32MZ
Compiler
NECTO Studio
MCU
PIC32MZ2048EFH100
Discover how linear magnetic displacement sensors redefine precision in countless industries, offering a world of opportunities for accurate position tracking and control
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Hardware Overview
How does it work?
Magnetic linear Click is based on the HMC1501, a linear magnetic displacement sensor from Honeywell. The key feature of the HMC1501 IC is the high accuracy of the magnetic field sensing. Unlike most of the magnetic sensors on the market which rely on the Hall-effect, the integrated sensors of the HMC1501 IC are produced using the Honeywell’s proprietary Anisotropic Magneto-Resistive (AMR) technology, which yields an absolute magnetic angle sensing with the angular error of only 0.07° in the range of ±45°. The magneto-resistive sensing elements form a single saturated-mode Wheatstone bridge, positioned in the XZ plane (parallel with the surface of the IC). The bridge is positioned towards the edge of the IC casing, allowing which is the optimal position for linear sensing applications. The IC outputs an analog differential voltage with respect to the angle of the magnetic field. The voltage from the selected mikroBUS™ power rail is directly applied to the internal Wheatstone bridge
of the HMC1501. By construction, in the absence of the magnetic field, its outputs will be set at half the supply voltage (with the small offset of 3mV/V typically). The same applies if there is a magnetic field present, but it is positioned at 0° (zero-crossing) in respect to the bridge. In both cases all the magneto-resistive elements forming the bridge, will have identical resistances. Once the magnetic field is applied in any direction in the range of ±45°, the bridge will become unbalanced, resulting with voltage change on the outputs. Outputs of the Wheatstone bridge are routed to the operational amplifier, which serves as the buffer for the A/D converter. For this purpose, only a single channel of the MCP6022, a dual rail-to-rail op-amp from Microchip, is used. This op-amp is biased to half the power supply voltage and has a gain of 25. This buffered signal is then used as the input for the A/D converter. Magnetic linear click uses the MCP3201, a 12-bit A/D converter (ADC) with the SPI Interface, produced by Microchip. This
ADC has a high resolution which can be used even for more demanding applications. At 0°, the ADC will output half of its full-scale (FS) value, and it will swing towards 0 if the angle of the magnetic field is positioned towards the negative direction, and 4095 if the angle of the magnetic field is positioned towards the positive direction. This ADC has a dedicated voltage reference input pin, allowing ADC conversion within the range of the input signal. The converted output value can be read via the SPI interface, routed to the mikroBUS™ SPI pins for easy interfacing with a vast number of different microcontrollers (MCUs). This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this 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.
Features overview
Development board
Flip&Click PIC32MZ is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32MZ microcontroller, the PIC32MZ2048EFH100 from Microchip, four mikroBUS™ sockets for Click board™ connectivity, two USB connectors, LED indicators, buttons, debugger/programmer connectors, and two headers compatible with Arduino-UNO pinout. Thanks to innovative manufacturing technology,
it allows you to build gadgets with unique functionalities and features quickly. Each part of the Flip&Click PIC32MZ development kit contains the components necessary for the most efficient operation of the same board. In addition, there is the possibility of choosing the Flip&Click PIC32MZ programming method, using the chipKIT bootloader (Arduino-style development environment) or our USB HID bootloader using mikroC, mikroBasic, and mikroPascal for PIC32. This kit includes a clean and regulated power supply block through the USB Type-C (USB-C) connector. All communication
methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, user-configurable buttons, and LED indicators. Flip&Click PIC32MZ development kit allows you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
2048
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
524288
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Flip&Click PIC32MZ as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for Magnetic linear Click driver.
Key functions:
magneticlinear_read_data- This function reads Magnetics Linear data
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* \file
* \brief Magneticlinear Click example
*
* # Description
* This application reads magnetics linear data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Device initialization.
*
* ## Application Task
* Reads magnetic linear data and logs it to USB UART every 500ms.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "magneticlinear.h"
// ------------------------------------------------------------------ VARIABLES
static magneticlinear_t magneticlinear;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
magneticlinear_cfg_t cfg;
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, "---- Application Init ----" );
// Click initialization.
magneticlinear_cfg_setup( &cfg );
MAGNETICLINEAR_MAP_MIKROBUS( cfg, MIKROBUS_1 );
magneticlinear_init( &magneticlinear, &cfg );
}
void application_task ( void )
{
uint16_t magnetic_data;
magnetic_data = magneticlinear_read_data( &magneticlinear );
log_printf( &logger, " Magnetic Linear data : %u\r\n", magnetic_data );
Delay_ms ( 500 );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
