Zoltan Hudak / Mbed OS HMC1501_Hello

Example program for the HMC1501 magnetic 90° angle sensor connected to a HX711 high precision 24-bit programmable analog-to-digital converter (ADC) .

Dependencies:   HMC1501 HX711

Example program for the HMC1501 magnetic 90° angle sensor. The HMC1501 analog output is connected to a HX711 high precision 24-bit analog to digital converter module.

HMC1501

100


The Honeywell HMC1501 is a miniature surface mount sensor for linear, 90° angular, or rotary displacement designed for magnetic saturating field sensing. The HMC1501 contains a single saturated-mode Wheatstone bridge sense element that creates an output voltage with respect to the direction of the magnetic flux passing over the sensor surface. It's a cost effective and space-efficient solution for high volume OEM designs. Applications for the HMC1501 sensor include Position Sensing, Rotary speed and angle detection, and non-contact precision location measurement systems. The HMC1501 sensor utilize Honeywell’s Anisotropic Magneto-Resistive (AMR) technology that provides advantages over hall-effectbased magnetic sensors. It is able to resolve better than tenths of a degree or tenths of millimeters, withstand large variations in magnet-to-sensor gaps, and exhibit insensitivity to shocks and vibrations.

Wiring of a connection with an HX711 Analog-to-Digital converter module:

https://os.mbed.com/media/uploads/hudakz/hmc1501_demo_wiring.png

Used libraries:

Import libraryHMC1501

Library for the HMC1501 magnetic 90° angle sensor.

Last commit 19 Sep 2020 by Zoltan Hudak

Import libraryHX711

Library for communication with the HX711 24-Bit Analog-to-Digital converter.

Last commit 19 Sep 2020 by Zoltan Hudak

main.cpp

Committer:
hudakz
Date:
2020-09-19
Revision:
0:7eed1f44df4a
Child:
1:668c95f5e6f9

File content as of revision 0:7eed1f44df4a:

#include "mbed.h"
#include "HX711.h"
#include "HMC1501.h"

//
DigitalOut      led1(LED1);
HX711           hx711(3.2f, D2, D3, 32);    // avdd in Volts, sck pin, dout pin, gain
HMC1501         hmc1501(-35.5, 47.05);      // measured by rotating a magnet: minV [mV], maxV [mV]
Ticker          ticker;
volatile bool   tick = false;
//

/**
 * @brief
 * @note
 * @param
 * @retval
 */
void onTick()
{
    tick = true;
}

/**
 * @brief
 * @note
 * @param
 * @retval
 */
int main()
{
    printf("Starting...\r\n");
    ticker.attach_us(onTick, 1000 * 1000);   // 500ms
    hx711.powerUp();
    while (true) {
        if (tick) {
            tick = false;
            led1 = !led1;
            if (hx711.isReady()) {
                float mV = hx711.read();    // read voltage in mV
                printf("hx711 voltage \t= %fmV\r\n", mV);
                printf("hmc1501 offset \t= %f mV\r\n", hmc1501.getOffset());
                printf("hmc1501 angle \t= %f deg\r\n", hmc1501.angle(mV));
                printf("-------------------------------------------\r\n");
            }
        }
    }
}