DD-301/302/401/402 Series Reflective Photoelectric Switch — Wire-Lead OEM Type
The close-range eye inside printers, note counters, kiosks and vending mechanisms: 5 mm reflective sensing that wires straight to a 5 V board.
- 5 mm rated distance on 90% white paper — no reflector, no slot
- DC5–24V ±10%: same part on logic boards and 24 V rails
- Horizontal (301/401) or vertical (302/402) optical axis
- Dark-ON (301/302) or Light-ON (401/402) by model — no inverter needed
- 940 nm invisible IR, 500 Hz+ switching, NPN output
Built for the Inside of a Machine, Not the Outside
Most photoelectric catalogues start at conveyor scale. The DD-301/302/401/402 series starts where OEM engineers actually live: a few millimetres above a sheet of paper, a card track or a feed pawl, inside a housing where every millimetre and every interface component counts. The sensor reads the reflection directly off the target surface at up to 5 mm — thin media never has to thread through a fork, and no reflector needs mounting on the far side.
Because the emitter is a 940 nm GaAs infrared source and the output is a plain NPN open-collector, the part behaves predictably next to shop lighting and connects to microcontroller inputs and PLCs alike. Pick the optical axis (horizontal or vertical) and the logic (Dark-ON or Light-ON) from the model table and the sensor drops into the design without an inverter stage.
Same electronics, two optical orientations: side-sensing for media edges, top-sensing for media paths running underneath.
Model Selection Table
| Model | Detection Method | Sensing Distance | Output |
|---|---|---|---|
| DD-301 / DD-301A | Diffuse reflective, horizontal (side-sensing) optics | 5 mm (90% reflectance white paper) | NPN, Dark-ON (ON when beam blocked / no reflection) |
| DD-401 / DD-401A | Diffuse reflective, horizontal (side-sensing) optics | 5 mm (90% reflectance white paper) | NPN, Light-ON (ON when reflection received) |
| DD-302 / DD-302B | Diffuse reflective, vertical (top-sensing) optics | 5 mm (90% reflectance white paper) | NPN, Dark-ON (ON when beam blocked / no reflection) |
| DD-402 / DD-402B | Diffuse reflective, vertical (top-sensing) optics | 5 mm (90% reflectance white paper) | NPN, Light-ON (ON when reflection received) |
Common ratings: DC5–24V ±10% supply, 940 nm GaAs IR emitter, switching frequency 500 Hz or higher, IP50, wire-lead termination. Operating temperature range and lead length — contact the factory for confirmation.
Note: general-purpose detection sensors, not IEC 61496-certified safety components — do not use them alone for personnel protection.
Typical Applications
Paper Path Sensing in Printers
Detects sheet presence directly off the paper surface at millimetre range — no slot to thread the media through.
Note & Card Handling Equipment
Close-range reflection off notes and cards suits ATMs, counters, kiosks and card readers; 500 Hz+ keeps up with feed rates.
5 V Logic Board Integration
DC5–24V supply lets the sensor hang straight off the control board rail — no regulator stage, no interface circuit.
Small-Part Presence Inside Mechanisms
Horizontal and vertical optics let designers aim the axis to suit the mechanism instead of redesigning the mount.
Frequently Asked Questions
What is the rated sensing distance, and what does the 90% white paper condition mean?
The rated distance is 5 mm, measured against a standard 90%-reflectance white paper target. Darker or less reflective materials return less light, so plan for a shorter working distance with such targets and validate on real media during design-in.
How do I pick between DD-301, DD-401, DD-302 and DD-402?
Two choices set the model. Optical orientation: DD-301/DD-401 sense sideways (horizontal), DD-302/DD-402 sense from the top (vertical). Output logic: DD-301/DD-302 are Dark-ON (output ON when no reflection is received), DD-401/DD-402 are Light-ON (output ON when reflection is received). The A/B suffixed variants share the same logic as their base models.
Can this sensor really run on a 5 V control board?
Yes. The supply range is DC5–24V ±10%, covering 5 V logic rails and 24 V industrial supplies with the same part — one of the main reasons OEMs design this series into printers, kiosks and appliance mechanisms.
Is the output NPN or PNP, and can the logic be switched on site?
All models are NPN open-collector. The Light-ON/Dark-ON logic is fixed per model number — there is no control wire — so choose the polarity your controller expects at ordering time, or use both variants across the design.
How fast can it count passing objects?
Switching frequency is 500 Hz or higher, which comfortably covers sheet feeding, card transport and small-part escapement speeds at the 5 mm working range.
Can it be used in wet or washdown locations?
No. The series is rated IP50 — dust-protected only — and is intended for dry equipment interiors. For splash-exposed mounting choose an IP65-rated sensor such as the BGS-CX441/CX442, or IP67 such as the BGS-CX61.
Is this sensor suitable for safety guarding?
No. It is a general-purpose OEM detection component, not an IEC 61496-certified safety device, and must not be used alone for personnel protection.
Do you support OEM volume pricing and samples?
Yes — this series is built for volume OEM integration. Contact the factory with your model split (orientation and logic), target annual volume and lead preferences; samples and certification documents are available on request.