KY-024 Linear, magnetic hall sensor

This module contains a Hall effect switch that detects and reacts to magnetic fields. In the idle state, when no external magnetic field is present, the output voltage is typically half the supply voltage. When a south magnetic pole approaches the marked side of the sensor, the output voltage increases. A north magnetic pole, on the other hand, lowers the output voltage. These fluctuations are symmetrical and enable precise threshold measurements.

The sensor emits a digital high signal as soon as a preset threshold value is exceeded. This threshold value is set via a rotary potentiometer and compared with the measured value of the sensor by the built-in LM393 comparator. If the set value is exceeded, the sensor outputs a logic high signal.

The digital output signals whether a magnetic field has been detected, while the analog output provides the direct measured value of the sensor unit. Two LEDs indicate the operating status: LED1 indicates that the sensor is supplied with voltage, and LED2 lights up when a magnetic field has been detected.

This module is ideal for applications where the detection and measurement of magnetic fields is required, such as in speed sensors, position sensors or safety systems. With the AH49E chipset and the LM393 comparator, it offers a reliable and precise solution for magnetic field detection. The sensor works with a supply voltage of 5V and offers an accuracy of 9 to 12 bits.

User note

This sensor is ideally suited for threshold value measurement. This means that the sensor emits a digital high signal as soon as a threshold value set by the user on the rotary potentiometer is exceeded. It should be noted here that the digital signal is a comparison of the value set on the rotary potentiometer and the measured value on the sensor, which are then compared by the LM393 comparator installed on the board. The set value of the rotary potentiometer is the threshold value, which is used to define a logical high signal.

Digital output: If a magnetic field is detected, a signal is output here

Analog output: Direct measured value of the sensor unit

LED1: Indicates that the sensor is supplied with voltage

LED2: Indicates that a magnetic field has been detected

Functionality of the sensor

This sensor has two functional components on its circuit board: The front sensor unit, which physically measures the environment and outputs it as an analog signal to the second unit, the comparator. The comparator compares the measured value of the sensor with the value set on the rotary potentiometer and outputs a logical high signal on the digital pin and LED L1 if the value on the rotary potentiometer is exceeded.

Please note: The signal is inverted. If a high value is measured, this results in a lower voltage value at the analog output.

The rotary potentiometer can be set as follows:

Pin assignment

Analog sensor, therefore the following must be considered: The Raspberry Pi has, in contrast to the Arduino, no analog inputs or there is no ADC (analog digital converter) integrated in the chip of the Raspberry Pi. This limits the Raspberry Pi, if you want to use sensors, which do not output digital values, but a continuously changing value (example: potentiometer -> different position = different voltage value).

To avoid this problem, our sensor kit X40 contains the KY-053, a module with a 16-bit ADC, which you can use on the Raspberry to expand it with 4 analog inputs. This module is connected to the Raspberry Pi via I2C, takes over the analog measurement and transfers the value digitally to the Raspberry Pi.

So we recommend to connect the KY-053 module with the mentioned ADC in between for analog sensors of this set. You can find more information on the KY-053 Analog Digital Converter information page.

Code example

Attention! To use this module in combination with the KY-053 Analog-Digital-Converter, a virtual environment must be set up. All the necessary information can be found here.

#!/usr/bin/python
# coding=utf-8
import time
import board
import busio
import adafruit_ads1x15.ads1115 as ADS
from adafruit_ads1x15.analog_in import AnalogIn
import gpiozero

# Create the I2C bus
i2c = busio.I2C(board.SCL, board.SDA)

# Create the ADC object using the I2C bus
ads = ADS.ADS1115(i2c)

# Create single-ended input on channels
chan0 = AnalogIn(ads, ADS.P0)
chan1 = AnalogIn(ads, ADS.P1)
chan2 = AnalogIn(ads, ADS.P2)
chan3 = AnalogIn(ads, ADS.P3)

delayTime = 1
Digital_PIN = 24

input = gpiozero.DigitalInputDevice(Digital_PIN, pull_up=None, active_state=True)

while True:
    analog = '%.2f' % chan0.voltage
 
    # Output to the console
    if input.is_active == False:
        print ("Analog voltage value:", analog,"V, ","Limit value: not yet reached")
    else:
        print ("Analog voltage value:", analog, "V, ", "Limit value: reached")
        print ("---------------------------------------")
 
    time.sleep(delayTime)