SS39ET/SS49E/SS59ET Series Linear Position Sensor ICs

2 Honeywell

Sensing and Control

Building Security

A secure electronic lock can be designed using an array of

linear magnetic sensors configured to detect a specific

magnetic pattern. If a strong external magnet were brought in

proximity to the array, it would be read as a random attempt

and could trigger an alarm. The array of linear Hall-effect

sensors could be used to unlock the system only if the

magnetic field read by each sensor is of the correct polarity

and within acceptable amplitude limits.

Figure 3. Electronic Locks

Without reproducing the exact magnetic flux pattern, it would

be virtually impossible to unlock the system with a single, or

even multiple, strong magnets. Tiny Honeywell SS39ET

Surface-Mount Linear Hall-effect Sensor ICs would provide

the needed sensitivity, output and very small size.

Customer Benefits

Small: Subminiature sensors easily fit into tight spaces

Flexible: Surface-mounting allows for a low-profile array on

a PC board

Energy efficient: Low voltage capability down to 2.7 V

High volume use: Low cost and taping option for automatic

component placement make this product suitable for high-

volume production

Water Pump Control

A water pump is essentially a special application of an electric

motor. These pumps are commonly manufactured for home

appliances.

Figure 4. Washing Machine

A linear Hall-effect sensor

generates an enhanced

control signal for better

resolution of the rotor

position, which can

improve the motor's

efficiency.

A crude RPM measurement

would verify that the pump is

working properly. The output of

the sensor may be used as an

alarm or a shut-off signal to help

prevent motor overload.

Figure 5. Aquarium Pump

A pump may use one or more valves, engage a clutch or gear

to begin, or move a lever or piston a specified distance. The

linear Hall-effect sensor IC can be used to verify that the valve,

clutch, lever or piston is in the specified position.