Hall Sensor reacts to magnetic field and changes its output depends on the polarity of magnet and magnetic field strength still now used in many applications, by using this types of sensor we can create multipurpose hall effect sensor circuit.
Here taken Hall Effect Sensor DRV5013 from texas instruments, it is a Digital Latch Hall Effect Sensor and operates with wide voltage ranges (2.5 to 38V) and provides bipolar switching, it has reverse supply protection upto -22 Volts and also output short circuit protection with current limitation feature. The DRV5013 available in through hole and surface mount packages.
This hall effect sensor has only three pins and fabricated in small size hence it can easily implemented in the design of Hand held electric tools, power tools, tachometer and valve and solenoid etc..
This sensor output state is depends on the magnetic field perpendicular to the package, here a South Pole near front side (Marked side of package) causes the output to pull low. Make sure to position the magnet south pole to face the sensor.
In this article two different application circuit developed based on hall effect sensor DRV5013. It can be modified to any magnetic sensing & switch or alarm circuit (Multipurpose..).
1. Hall Effect Sensor Switch
In this circuit any load can be controlled depends on the hall sensor output, A SPDT Relay is connected at the output stage of hall sensor. When the magnet south pole appears near to DRV5013, then the output becomes low, it makes the Q1 transistor to open and hence the +ve supply reaches Q2 transistor base through R3 resistor. Q2 transistor becomes close when the base bias appears. Then the LED and Relay gets supply and comes to turn ON state.
2. Hall Effect Sensor Alarm Circuit
This circuit works same as the previous circuit but at the output stage Buzzer placed to give alert sound. This circuit can be used as door open alarm, desk drawer open alarm, object alarm etc…