Aleph Opto Sensors – Typical Applications

Application Interrupter Type Reflective Type Actuator Type
Aleph Opto Sensors Aleph Opto Sensors Aleph Opto Sensors
Office Automation Copy Machines Printers
FAX Machines Typewriters
Computer Printers Card – Tape Readers
FDD Laser Disks
Test Equipment Electric Scales Encoders
Speed Meters Time Recorders
Home Equipment Sewing Machines Video Disks Fan Heaters
Audio CDs VCRs Air Conditioning
Others Auto Vending Machines Medical Equipment Pre-payed Card Readers
ATM Equipment Amusement Games Factory Automation


Aleph Opto Sensors Opto sensor consists of a light emitting element which transforms an electrical signal to an optical signal, and a light receiving element which transforms the optical signal to an electrical signal. Both of these elements are housed in one package, making the opto sensor essentially a non- contact switch. Opto sensors detect presence, length, number, etc., of objects, using visible or infrared light which is blocked or reflected by the object. Aleph Opto Sensors

Interrupter type opto sensors

This is the most popular type of opto sensors. Emitting and receiving elements are housed in one package and face each other. They sense presence of objects in the sensing slot, without physical contact. Selection of aperture widths : 0.5mm, 1.0mm and 1.3mm is available to achieve the required sensing resolution. Selection of sensing slot widths: 3mm, 5mm and 10mm is available for the required interrupter size. To meet as many applications as possible, we have provided many additional features, such as: dustproof and waterproof package, pin and insulated wire terminations, phototransistor, photo Darlington and logic IC outputs, snap action and screw mounting options, etc.

Reflective type opto sensors

Aleph Opto Sensors Emitting and receiving elements are mounted on the same surface at a fixed angle to each other. They detect presence or position of an object through light reflection. Use of high contrast materials (e.g. white and black) is recommended to achieve high sensing resolution. For use with numerous applications, we have provided these sensors with different sensing distances, package styles, sizes, mounting types, output configurations, etc.

Actuator type opto sensors

Aleph Opto Sensors This sensor is a combination of the interrupter opto sensor with a mechanical actuator, which physically blocks the light path between emitting and receiving elements. Normally the actuator blocks the beam path and opens it only when it is mechanically actuated by the sensed object. Most actuators travel in only one direction (Fig. 3), but we have also designed a one that senses movement in three directions. For use with numerous applications, we have also provided different package and actuator styles and sizes, mounting types, output configurations, etc.  

Application Notes

Interrupter type opto sensors

  • Do not use (interrupter) materials which are translucent to visible and infrared light.
  • For proper operation in dusty and/or humid environment, select dustproof and/or waterproof sensors.
  • Avoid using opto sensors in environments where high intensity of ambient light may cause erroneous operation.

Reflective type opto sensors

  • Use high contrast materials for the sensed objects.
  • Choose the sensed area to be as wide as practical, to ensure highest sensing resolution.
  • For proper operation in dusty environment, select dustproof sensors.
  • Avoid using opto sensors in environments where high intensity of ambient light may cause erroneous operation.
  • Locate sensor with its active surface facing down to protect from dust contamination or use sensors with dustproof covers.
  • If soft materials (e.g. paper) are being sensed, it is recommended that such material wipes (cleaning action) the active surface of the sensor.

Actuator type opto sensors


  • There are two types of actuator sensors: spring loaded and counterweight. The spring loaded actuator can be located in any position, but the counterweight one must be positioned as shown on the drawings.
  • Actuator type sensors are designed to be mounted on sheet metal. If mounted on printed circuit board or plastic plate, proper attachment to such materials must be provided to avoid mechanical shift. When more adhesion is needed, glue may be used.
  • Mounting hole size and shape vary between models; see recommended mounting hole dimensions for each model.
  • If mounting hole has a punch burred edges, insert the sensor from the other side (see Fig. 5). Reversed insertion may cause mechanical damage to the sensor.

Aleph Opto SensorsMechanical

  • Proper operating angle is important to achieve stable operation; see specification sheets.
  • Avoid establishing operating point (OP) very close to total travel point (TTP) to guard against unstable operation (see Fig. 6).
  • When used for high speed sensing, make sure that the actuator has enough time to return to free position (FP) after each actuation.
  • When Aleph Opto Sensorsusing spring loaded actuator type sensors, make sure that the spring pressure on the actuator will allow proper movement of the sensed object. Keep in mind that the actuator will wear through repeated mechanical contact with the sensed object.


  • When using models without internal current limiting resistors in series with the input LED, adding external resistor is necessary. Calculate the resistor’s value for the required supply voltage range (5 through 24v).
  • Models with internal current limiting resistors have specified supply voltages; see specification sheets.
  • Check maximum ratings and electrical specifications before selecting a sensor.
  • Standard supply voltage is 5V; if 12V or 24V is required please contact ALEPH.
  • If your application requirements cannot be met by any of our standard models, due to any of the reasons listed below, please contact ALEPH:
    • high speed, or extremely low speed
    • long life
    • wire style (color, UL grade, gauge, length, etc.)
    • connector style
    • actuator style
    • package style
    • mounting plate thickness, etc.