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BIDIRECTIONAL INFRARED VISITOR COUNTING SENSORS

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D3 SERIES

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1. Description

SensMax D3 series bidirectional infrared visitor counting sensors are wireless, battery-powered devices designed for accurate visitor counting in areas with distinct pedestrian flows. The family includes the SensMax D3 Pro, SensMax D3 LR, SensMax D3 SLR models, as well as real-time modifications SensMax D3 LR TS and SensMax D3 SLR TS.

The sensors operate on the principle of crossing an infrared beam. A distinctive feature of the D3 series is the use of three focused infrared beams, which allows for highly accurate determination of the visitor's direction of movement to IN or OUT.

Each sensor structurally consists of two physical blocks: Transmitter (TX) and Receiver (RX), installed strictly opposite each other on the walls or openings of corridors, doors, or entrances. The transmitter emits an invisible focused infrared barrier. Each crossing of this barrier is registered by the receiver, which instantly determines the direction of passage and saves the data in its internal memory or transmits it further into the system in real time.

Key benefits:

  • Direction of movement detection (IN/OUT): Separate counting of incoming and outgoing visitors for detailed attendance analysis.
  • 100% wireless operation: Powered by standard AA batteries eliminates the need for routing power or communication cables.
  • Easy installation: Installation takes a few minutes and is performed on any flat surface using strong double-sided tape from the delivery kit or specialized mounting brackets.
  • Tamper and block protection: Devices are equipped with a built-in sound signal and a function for sending a notification to the software if the infrared beam is blocked or obstructed by a foreign object for a long time.
  • GDPR and privacy compliance: 100% compliant with personal data protection laws, as the sensors collect exclusively numerical passage statistics without video recording or registering personal data.
  • Occupancy tracking (for TS models): Ability to track the number of people inside a room in real time (Occupancy Tracking) with data transmission to LED screens (LED-391) and to the cloud.

2. Modifications and network architecture

Radio frequency options (868 / 915 / 920 MHz)

By default, all LR and SLR series devices (both sensors and collectors) are supplied configured to a frequency of 868 MHz. For regions with other radio frequency standards (USA, Asian countries, etc.) or upon special request, we produce modifications operating at frequencies of 915 MHz and 920 MHz.

The SensMax D3 family of bidirectional sensors is divided into two main groups according to the data transmission mode:

Standard D3 series (Batch transmission)

Sensors of this series accumulate hourly attendance statistics in the internal memory and automatically transmit it to the data collector (gateway) every 20 minutes. Suitable for standard retail analytics tasks.

  • SensMax D3 Pro: Wireless communication range up to 50 meters (in line of sight). Designed for small shops and offices.
  • SensMax D3 LR (Long Range): Operates at a frequency of 868 MHz (915/920 MHz upon request) with a wireless communication range of 150 to 250 meters. Optimal for supermarkets and multi-story stores.
  • SensMax D3 SLR (Super Long Range): Operates at a frequency of 868 MHz (915/920 MHz upon request) with a wireless communication range of up to 800 meters (up to 1000 meters in line of sight). Designed for large shopping centers, hypermarkets, and exhibition complexes.

D3 TS series (Real-time transmission)

TS series sensors transmit data on each passage instantly (in real time) or as 5-minute batches. Ideal for room occupancy control systems.

  • SensMax D3 LR TS: Operates at a frequency of 868 MHz (915/920 MHz upon request) with a wireless communication range of up to 150 meters.
  • SensMax D3 SLR TS: Operates at a frequency of 868 MHz (915/920 MHz upon request) with a wireless communication range of up to 800 meters.

3. Features and benefits of bidirectional counting

Unlike unidirectional systems, the D3 sensor family offers deeper analytics by separating directions of movement:

  • Separate accounting of IN and OUT: Allows you to accurately assess sales conversion, the distribution of flows within trading zones, and identify peak load periods.
  • Real-Time Occupancy control: The use of D3 TS models in conjunction with SMX TS gateways allows you to calculate the number of visitors inside the premises at the current moment in real time.

4. Application

Retail stores, supermarkets, shopping centers, libraries, museums, train stations and airports, public and office buildings, Washroom zones. When installed in a specialized IP68 waterproof housing, the sensors can be operated outdoors (in parks, on pedestrian streets, ecological trails).

5. Delivery kit

The standard delivery kit for SensMax bidirectional sensors includes:

  • Transmitter block (TX) - 1 pc.
  • Receiver block (RX) - 1 pc.
  • AA 1.5V alkaline batteries - 4 pcs.
  • L-type mounting brackets - 2 pcs.

6. Models comparison

Parameter SensMax D3 Pro SensMax D3 LR SensMax D3 SLR SensMax D3 LR TS SensMax D3 SLR TS
Radio frequency 2.4 GHz 868 / 915 / 920 MHz* 868 / 915 / 920 MHz* 868 / 915 / 920 MHz* 868 / 915 / 920 MHz*
Operation mode Batch (every 20 mins) Batch (every 20 mins) Batch (every 20 mins) Real time / 5 mins Real time / 5 mins
Operating conditions Indoor / Outdoor (in IP68) Indoor / Outdoor (in IP68) Indoor / Outdoor (in IP68) Indoor / Outdoor (in IP68) Indoor / Outdoor (in IP68)
Communication range Up to 50 m Up to 250 m Up to 800 m Up to 150 m Up to 800 m
Compatible collectors SMX PRO SMX LR SMX SLR SMX LR TS SMX SLR TS
Internal memory 25 days of hourly data 25 days of hourly data 25 days of hourly data 2000 records 2000 records
Infrared beams 3 beams 3 beams 3 beams 3 beams 3 beams
Housing material ABS plastic ABS plastic ABS plastic ABS plastic ABS plastic
Standard color Black / White Black / White Black / White Black / White Black / White
Protection class (IP) IP54 (IP68 in protection) IP54 (IP68 in protection) IP54 (IP68 in protection) IP54 (IP68 in protection) IP54 (IP68 in protection)
Dimensions (one unit) 67×67×25 mm 67×67×25 mm 67×67×25 mm 67×67×25 mm 67×67×25 mm
Power supply 4 AA batteries (2 pcs. each) 4 AA batteries (2 pcs. each) 4 AA batteries (2 pcs. each) 4 AA batteries (2 pcs. each) 4 AA batteries (2 pcs. each)
Battery life Up to 1 year Up to 1 year Up to 1 year Up to 1 year Up to 1 year

* Modifications for 915 MHz and 920 MHz are available upon special order.

7. Technical specifications

  • Operating principle: Interruption of three focused infrared beams (Bidirectional IN/OUT direction detection).
  • Aisle width:
  • Optimal: 1.0 m - 6.0 m.
  • Maximum: up to 9.0 m.
  • Counting accuracy:
  • 95% with aisle width up to 3.0 m.
  • Margin of error: With an aisle width of more than 3.0 m, the accuracy decreases by approximately 0.6% - 1.0% for each additional meter (depends on the density of the flow of people).
  • Infrared radiation angle: Beam divergence is 6°.
  • Serial numbers syntax: Unique identifier starting with the prefix "04" (for example, 040000123).
  • Tamper protection:
  • If the IR beams are blocked (obstructed) continuously for a long time (usually more than 15 minutes), the receiver block emits a warning sound.
  • The sensor transmits a blocking flag to the gateway, which triggers a fault warning in the SensMax software.
  • Operating temperature: from -20°C to +55°C (can be extended to -30°C when using high-quality 1.5V lithium batteries, such as Energizer Ultimate Lithium).
  • Housing dimensions: 67 × 67 × 25 mm (for each TX and RX block).
  • Weight: ~65 g per unit (without batteries).

Recommendations for choosing batteries

To ensure stable operation of the sensors during the entire declared service life (from 6 to 12 months), it is recommended to use high-quality batteries:

  • High-quality 1.5V Alkaline batteries: Optimal choice for standard indoor operating conditions.
  • 1.5V Lithium batteries: Recommended for outdoor installation or unheated rooms. Lithium batteries maintain stable operating voltage at low temperatures (down to -30°C) and have a long shelf life.

8. Sensor elements and LED indicators

The receiver and transmitter blocks are equipped with status LED indicators and buttons for configuration, diagnostics, and testing.

Front view (Receiver RX)

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[1] IR Link LED - Orange
[2] DIR A LED - Red (OUT direction)
[3] DIR B LED - Red (IN direction)
[4] Status LED - Green
[5] Device serial number (starts with "04")

Rear / inside view (RX)

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[6] Battery compartment (2x AA)
[7] Pairing button

Receiver RX indicators table

Element / LED Type / Color Status Description
[1] Link LED LED / Orange Blinking Indicates that the transmitter and receiver units are correctly aligned relative to each other and the IR barrier is active.
[2] DIR A LED LED / Red Blinking Lights up with each visitor count in the OUT direction.
[3] DIR B LED LED / Red Blinking Lights up with each visitor count in the IN direction.
[4] Status LED LED / Green Blinking Blinks rarely (once every 10 sec) in standby mode. Blinks fast (1 time per sec) during visitor passage (fast scanning mode for direction detection).
[5] Pairing button Button Press 1 time Internal button for pairing the receiver with the SMX gateway and checking the connection quality.

Front view (Transmitter TX)

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[1] Status LED - Green

Rear / inside view (TX)

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[2] Battery compartment (2x AA)
[3] Aisle width selector (AISLE WIDTH)

Transmitter TX indicators table

Element / LED Type / Color Status Description
[1] Status LED LED / Green Blinks Blinks rarely (once every 10 sec) in standby mode. Blinks fast (1 time per sec) during visitor passage (fast scanning mode for direction detection).
[3] AISLE WIDTH Selector / Switch Setting Switch for infrared beam power in accordance with the aisle width. For details, see the section "Adjusting beam power (AISLE WIDTH)".

9. Supported data collectors and gateways

For D3 family sensors, a stationary data collector (gateway) is required to receive and further forward statistics:

For standard sensors (D3 Pro, D3 LR, D3 SLR):

  • SensMax SMX PRO gateway: Serves up to 5 D3 Pro sensors with a communication range of up to 50 meters.
  • SensMax SMX LR gateway: Serves up to 30 D3 LR sensors with a communication range of up to 150-250 meters.
  • SensMax SMX SLR gateway: Serves up to 30 D3 SLR sensors with a communication range of up to 800 meters.
  • Backward compatibility: Standard D3 sensors are also backward compatible with previous generation TCPIP (Pro/LR/SLR) and 3G (Pro/LR/SLR) collectors, serving up to 5 (Pro) or 30 (LR/SLR) bidirectional sensors per device.

For real-time sensors (D3 LR TS, D3 SLR TS):

  • SensMax SMX LR TS gateway: Serves up to 20 real-time sensors with a communication range of up to 150 meters.
  • SensMax SMX SLR TS gateway: Serves up to 20 real-time sensors with a communication range of up to 800 meters.

10. Physical installation and alignment

Height and positioning

  • Recommended height: Install the sensors at a height of 1.5 - 1.6 meters from the floor level. This is the optimal height for fixing intersections by the body of an adult and a child, eliminating false triggering on bags, packages, or small animals.
  • Horizontal alignment: The Transmitter (TX) and Receiver (RX) blocks must be located strictly opposite each other on the same horizontal axis. Since D3 sensors use 3 beams, the accuracy of horizontal and vertical alignment is critically important for correctly recognizing passage directions.
  • Surface preparation: The surface before installation must be cleaned of dust and degreased. Installation is carried out on strong double-sided tape from the delivery kit or using screws.

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Direction orientation (DIR A / DIR B)

Proper orientation of the sensor blocks during installation is critical for the correct registration of visitor movement directions (IN / OUT):

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  • DIR A LED (on the RX receiver block) and its corresponding IR beams must be oriented out of the store (towards the street, shopping gallery, or corridor). Crossing the beams from the DIR A side is registered by the system as IN.
  • DIR B LED (on the RX receiver block) and its corresponding IR beams must be oriented inside the store (towards the trading floor or room). Crossing the beams from the DIR B side is registered as OUT.

Note

If you mix up the orientation of the blocks during installation, the statistics in the SensMax reports will be inverted (IN will be displayed as OUT, and vice versa). The counting direction can be manually adjusted in the SensMax software settings, however, to avoid unnecessary confusion and additional actions, it is recommended to initially set DIR A outward and DIR B inward.

Checking alignment

  1. Install batteries in both blocks and mount them opposite each other.
  2. Check the indication on the front panel of the Receiver (RX).
  3. Orange Link LED should blink periodically. This means that all 3 IR beams of the transmitter are successfully received by the receiver.

Green Status LED operation modes during alignment:

  • Standby mode: When the alignment is configured correctly and there are no visitors in the aisle, the green Status LED blinks rarely (once every 10 seconds). This is a normal energy-saving state.
  • Scanning mode: When a person passes, the sensor switches to fast scanning mode to determine the direction of movement, and the green LED blinks fast (1 time per second) during the passage and for several seconds after it.
  • Alignment error: !!! warning "blinks fast and continuously" Adjust the position of the blocks until the Status LED returns to the rare flashing mode (once every 10 seconds).

Adjusting beam power (AISLE WIDTH)

The AISLE WIDTH switch on the transmitter board (TX) allows you to adapt the power of the infrared beam to the actual width of the passage.

This is especially true for aisles with a large amount of glazing, shop windows, or mirror partitions. With excessive radiation power, the IR beam can be reflected from such surfaces, which can affect the accuracy of passage registration. Setting the selector to the position corresponding to the width of the passage optimizes the signal level and guarantees the maximum accuracy of the counting system.

Additional mounting accessories

When mounting in difficult conditions (uneven walls, corner passages, outdoor installation), the following branded accessories are used:

  • V-type swivel bracket: Allows you to rotate the sensor blocks at an angle of up to 180° horizontally for precise alignment.
  • L-type corner bracket: 90-degree bracket for mounting perpendicular to the wall.
  • Outdoor housing: Sealed protective housing (IP68) made of ABS plastic with a transparent window for outdoor installation in the open air.

11. Commissioning and pairing

Each receiver of the D3 series sensor must be paired (linked) to its data collector before starting work:

  1. Turn on the gateway: Connect the SensMax SMX data collector to the power source.
  2. Set the sensor power: Insert 2 AA batteries into the TX transmitter and 2 AA batteries into the RX receiver.
  3. Start the search mode on the collector:
  4. Find the pairing button on the collector body (located on the end side next to the USB port).
  5. Using a thin object (pencil, paper clip), briefly press the button.
  6. The Radio Link LED on the collector will start blinking, indicating the transition to the sensor search mode.
  7. Start pairing on the sensor:
  8. Open the RX receiver housing.
  9. Press the internal Pairing button once.
  10. The receiver will send a pairing packet to the gateway.
  11. Pairing confirmation:
  12. Upon successful pairing, the collector registers the sensor, synchronizes the built-in real-time clock with it.
  13. The indicator on the gateway will return to normal operation.
  14. The sensor will start counting, relying on accurate synchronized clocks.

Alternative pairing method (via collector web interface)

If the sensors are already mounted or you want to avoid disassembling the receiver housing to press the button, the binding can be done programmatically via the SensMax SMX data collector web interface:

  1. Connect to the collector web interface: Open the built-in collector settings web page in a browser.
  2. Go to the device list: On the Home tab, click the Edit device list button.
  3. Add a sensor: Click the add button and enter:
  4. Sensor serial number: printed on the device body (starts with the prefix "04").
  5. Security code: printed on the device body next to the serial number.
  6. Complete pairing: Save the settings. The collector will establish a connection with the sensor via the radio channel and synchronize the system time automatically. This may take from 5 to 20 minutes, depending on the type of sensor.

Checking radio communication quality with the collector

After pairing, it is recommended to check the stability of the radio signal directly at the site of future equipment installation:

  1. Place the collector at its permanent work location.
  2. Move the receiver (RX) to the proposed mounting point.
  3. Start communication test:
  4. Press the Pairing button on the RX receiver board.
  5. The sensor will send a test radio packet and display the result:
    • Connection is normal: The sensor will emit two short beeps and blink the green LED.
    • No connection: The sensor will emit one low long beep and blink the red LED.
  6. Adjustment: In case of uncertain connection, adjust the position of the collector or sensor. The test can be performed an unlimited number of times.

12. Time synchronization

For the correct formation of hourly and real-time reports, the accuracy of the internal sensor clocks is critically important.

Time synchronization is performed fully automatically during pairing and during each communication session of the sensor with the gateway. The gateway reads the exact time (NTP) and transmits it to the sensors.

Important

Please note that the sensor will not start counting visitors (and the LED indicators will not blink when crossing the beams) until the current date and time are set on the device. Initial configuration (synchronization) of time with the gateway is a prerequisite for the sensor to start working.

13. Certification and standards compliance

SensMax sensors are manufactured in accordance with strict international requirements for quality and environmental safety:

  • CE (Conformité Européenne): Compliance with EU safety, electromagnetic compatibility, and radio frequency spectrum standards.
  • RoHS (Restriction of Hazardous Substances): Products are manufactured without the use of harmful and hazardous substances.
  • GDPR Compliant: Full compatibility with European privacy laws. The sensors perform purely mathematical quantitative passage counting without collecting biometric, personal, or video data of visitors.

14. Ordering Information

Important: Radio frequency compatibility

When ordering equipment (sensors and gateways), make sure they work on the same radio frequency. By default, LR, SLR, and TS devices are shipped tuned to 868 MHz. If you require modifications for 915 MHz or 920 MHz, be sure to specify this when ordering (for example: SensMax D3 LR - 915 MHz). Equipment with different frequencies will not be able to communicate with each other.

Bidirectional sensors (batch transmission)

Model / Part Number Description Compatible collector
SensMax D3 Pro Wireless bidirectional counting sensor (up to 50 m) SensMax SMX PRO
SensMax D3 LR Wireless bidirectional counting sensor Long Range (868 MHz*, up to 150 m) SensMax SMX LR
SensMax D3 SLR Wireless bidirectional counting sensor Super Long Range (868 MHz*, up to 800 m) SensMax SMX SLR

Bidirectional sensors (real time)

Model / Part Number Description Compatible collector
SensMax D3 LR TS Wireless bidirectional real-time sensor (868 MHz*, up to 150 m) SensMax SMX LR TS
SensMax D3 SLR TS Wireless bidirectional real-time sensor Super Long Range (868 MHz*, up to 800 m) SensMax SMX SLR TS

Data collectors (gateways)

Model / Part Number Description Compatible sensors
SensMax SMX PRO Wireless data collector (Ethernet/Wi-Fi AP) SensMax D3 Pro
SensMax SMX LR Wireless data collector Long Range 868 MHz* (Ethernet/Wi-Fi AP) SensMax D3 LR
SensMax SMX SLR Wireless data collector Super Long Range 868 MHz* (Ethernet/Wi-Fi AP) SensMax D3 SLR
SensMax SMX LR TS Wireless real-time data collector (Ethernet/Wi-Fi AP) SensMax D3 LR TS
SensMax SMX SLR TS Wireless real-time data collector Super Long Range 868 MHz* (Ethernet/Wi-Fi AP) SensMax D3 SLR TS

Accessories

Model / Part Number Description Compatible sensors
V-type swivel bracket Plastic swivel bracket (up to 180° horizontally) All D3 series sensors
L-type corner bracket 90-degree bracket for perpendicular mounting All D3 series sensors
Outdoor housing Sealed waterproof protective box (IP68) All D3 series sensors

* Modifications for 915 MHz and 920 MHz are available upon special order.

Contacts

SensMax is a registered trademark. SensMax reserves the right to make changes to the products described herein without prior notice. The information contained in this publication regarding device applications and the like is provided solely for your convenience. SensMax disclaims all liability arising from this information and its use. The use of SensMax devices in life-support and/or safety-critical applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify, and hold harmless SensMax against any and all damages, claims, suits, or expenses arising from such use. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights of SensMax.