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UNIDIRECTIONAL INFRARED VISITOR COUNTING SENSORS

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S1 SERIES

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1. Description

SensMax unidirectional infrared visitor counting sensors are wireless, battery-powered devices designed for counting visitors in areas with distinct pedestrian flow aisles. The family includes the SensMax S1 Pro, SensMax S1 LR, and SensMax S1 SLR models.

The sensors operate on the principle of crossing an infrared beam. 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, and each interruption of this barrier (a person passing) is registered as a crossing and stored in the internal memory of the receiver.

Since these sensors use a unidirectional counting algorithm, they record any beam crossings without separating the direction of movement (meaning they do not separate incoming and outgoing visitors). To estimate the total visitor traffic volume in reports, the obtained total number of crossings is usually divided by two.

Key benefits:

  • 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 crossing statistics without video recording or registering personal data.
  • Automatic data collection: Automatic transmission of accumulated data over a radio channel in real time or in batches to SensMax SMX data collectors.

2. Modifications and network architecture

The SensMax S1 family of unidirectional sensors is designed for automatic data transmission. The receiver block periodically transmits the accumulated hourly statistics via a wireless radio channel to the stationary SensMax SMX data collector (gateway) located within the network's range. The gateway then sends the data to a central database or cloud reporting portal via Wi-Fi or Ethernet.

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 family includes the following modifications:

  • SensMax S1 Pro (Standard): Communication range up to 50 meters. For small stores and offices.
  • SensMax S1 LR (Long Range): Communication range up to 250 meters. For supermarkets and multi-story stores.
  • SensMax S1 SLR (Super Long Range): Communication range up to 800 meters (up to 1000 meters in open space). For large shopping centers, museums, and industrial facilities.

3. Features and benefits of unidirectional counting

SensMax unidirectional sensors are the optimal choice for most small and medium-sized commercial facilities (retail stores, pharmacies, service salons, offices).

Key solution benefits:

  • Simplicity and clarity of reports: The sensor records every intersection of the IR beam. In the SensMax Software, this data is displayed as a single, simple, and intuitive line on the chart. This eliminates confusion with "IN/OUT" directions, which often arises for users when analyzing bidirectional systems.
  • Mathematical accuracy (Division by 2): In dead-end rooms (where entry and exit are made through the same door), each visitor crosses the beam twice - when entering and when exiting. The SensMax Software automatically divides the total number of registered crossings by 2, providing the business owner with accurate statistics of the real number of visitors.
  • Configuration flexibility for transit zones: If the sensor is installed in a transit (through) zone where people move only in one direction without returning, the divide-by-2 function in the SensMax Software settings can be easily disabled.

Using a unidirectional model allows you to get clean, representative attendance statistics without excessive complexity when setting up reports.

4. Application

Retail stores, shopping centers, libraries, museums, restrooms, office buildings, public exhibition areas (and when using a special protective housing - also in outdoor areas).

5. Delivery kit

The standard delivery kit for SensMax unidirectional 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 S1 Pro SensMax S1 LR SensMax S1 SLR
Operating conditions Indoor / Outdoor (in special protective housing) Indoor / Outdoor (in special protective housing) Indoor / Outdoor (in special protective housing)
Data collection method Automatic wireless Automatic wireless Automatic wireless
Radio frequency 2.4 GHz 868, 915, 920 MHz* 868, 915, 920 MHz*
Communication range Up to 50 m Up to 250 m Up to 800 m
Compatible collectors SMX PRO SMX LR SMX SLR
Internal memory 25 days of hourly data 25 days of hourly data 25 days of hourly data
Infrared beams 1 beam 1 beam 1 beam
Housing material ABS plastic ABS plastic ABS plastic
Standard housing color Black or White Black or White Black or White
Protection class (IP) IP54 (IP68 in special protective housing) IP54 (IP68 in special protective housing) IP54 (IP68 in special protective housing)
Dimensions (one unit) 67×67×25 mm 67×67×25 mm 67×67×25 mm
Power supply 4 AA batteries (2 pcs. per TX/RX block) 4 AA batteries (2 pcs. per TX/RX block) 4 AA batteries (2 pcs. per TX/RX block)
Battery life Up to 2 years Up to 2 years Up to 2 years

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

7. Technical specifications

  • Operating principle: Interruption of a focused infrared barrier (Unidirectional).
  • Aisle width:
  • Optimal: 1.0 m - 5.0 m.
  • Maximum: up to 10.0 m.
  • Counting accuracy:
  • 95% with aisle width from 2.0 m to 3.0 m.
  • Margin of error: With an aisle width of more than 3.0 m, the counting accuracy decreases by approximately 0.6% - 1.0% for each additional meter (depends on the density of the pedestrian flow).
  • Infrared radiation angle: Beam divergence is 6°.
  • Serial numbers syntax: Unique identifier starting with the prefix "03" (for example, 030000123).
  • Tamper protection:
  • If the infrared beam is blocked (obstructed) continuously for a long time (usually more than 15 minutes), the receiver block emits a warning sound.
  • S1 series sensors transmit a blocking flag to the gateway, which triggers a fault warning in the SensMax reporting 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 1.5V).
  • Housing dimensions: 67 × 67 × 25 mm (for each Transmitter and Receiver block).
  • Weight: ~60 g per unit (without batteries).

Recommendations for choosing batteries

To ensure stable operation of the sensors during the entire declared service life (up to 2 years), it is recommended to use only new 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 1.5V 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] Crossing LED - Red
[3] RF Link LED - Green
[4] Battery LED - Red
[5] Device serial number

Rear / inside view (RX)

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[6] Battery compartment
[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] Crossing LED LED / Red Blinks 1 time Lights up with each crossing of the IR beam by a pedestrian (passage registration).
[3] RF Link LED LED / Green Blinking Indicates an active radio communication session with the gateway.
[4] RF Link LED LED / Green Blinking Slow periodic blinking indicates that the device is turned on and operating normally.
[5] Battery LED LED / Red Blinking Indicates low battery level. Batteries should be replaced soon.
[6] Battery compartment Hardware N/A Located inside the housing. Holds 2 AA type batteries in each block (Transmitter and Receiver).
[7] Pairing button Button Press 1 time Internal button for pairing the receiver with the SMX gateway and checking connection quality with it.

Front view (Transmitter TX)

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[1] Power LED - Green
[2] Battery LED - Red
[3] IR Emitter

Rear / inside view (TX)

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[4] Battery compartment

Transmitter TX indicators table

Element / LED Type / Color Status Description
[1] Power LED LED / Green Blinks 1 time per 10 sec Indicates that the device is operating.
[2] Battery LED LED / Red Blinking Indicates low battery level. Batteries should be replaced soon.

9. Supported data collectors and gateways

For S1 family sensors, a stationary data collector (gateway) is required to receive and forward statistics:

  • SensMax SMX PRO gateway: Serves up to 5 S1 sensors with a communication range of up to 50 meters.
  • SensMax SMX LR gateway: Serves up to 30 S1 LR sensors with a communication range of up to 250 meters.
  • SensMax SMX SLR gateway: Serves up to 30 S1 SLR sensors with a communication range of up to 800 meters.
  • Note on legacy collectors: The S1 family is also backward compatible with legacy TCPIP (Pro/LR/SLR) and 3G (Pro/LR/SLR) data collectors, which support up to 10 (Pro) or 60 (LR/SLR) sensors.

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 height is optimal for fixing intersections by a person's torso, while eliminating false responses to low-hanging bags, packages, or small pets.
  • Horizontal alignment: The Transmitter (TX) and Receiver (RX) blocks must be installed strictly opposite each other on the same horizontal axis.
  • Surface preparation: The surface of walls or jambs before installation must be cleaned of dust and degreased. For quick mounting, use high-quality double-sided tape. ir_sensor_install.png

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 the receiver is stably receiving the IR signal from the transmitter.

It is possible to purchase additional mounting accessories

In places where walls are uneven, angled, or have ledges, use branded SensMax mounting brackets:

  • V-type plastic swivel bracket: Allows you to rotate the blocks at an angle of up to 180° horizontally for precise alignment on wide or corner aisles.
  • L-type corner bracket: 90-degree bracket for installing blocks perpendicular to the wall.
  • Commissioning in outdoor conditions: Use a special waterproof sealed plastic housing with clear glass (protection class IP68) to protect the sensors during outdoor operation (in parks, gardens, etc.).

11. Commissioning and pairing (S1 Family)

Each receiver of the S1 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 supply network.
  2. Set the sensor power: Insert 2 AA batteries into the S1 transmitter and 2 AA batteries into the S1 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 that the gateway is in the mode for finding new devices.
  7. Start pairing on the sensor:
  8. Open the S1 receiver housing.
  9. Press the internal Pairing button once.
  10. The receiver will send a pairing request to the collector.
  11. Pairing confirmation:
  12. Upon successful connection, the collector registers the sensor in memory and automatically synchronizes the current time and date with it.
  13. The Radio Link LED on the collector will stop blinking fast and return to normal operation.
  14. The sensor will start recording statistics based on the synchronized clock.

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 "03").
  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 successful sensor pairing, it is recommended to check the stability of the radio channel directly at the planned equipment installation point before its final mounting:

  1. Place the collector: Install and connect the SensMax data collector in its permanent location (for example, in a server room, switch cabinet, or office).
  2. Move to the sensor installation location: Move the paired receiver (RX) to the proposed mounting point (for example, to the aisle or entrance group).
  3. Start communication test:
  4. Press the Pairing button on the board inside the open receiver housing.
  5. The sensor will send a test radio packet to the collector and display the communication result using light and sound indications:
    • Connection is normal: The sensor will emit two short beeps and blink the green LED (RF Link LED). This confirms stable bidirectional data exchange.
    • No connection: The sensor will emit one low long beep and blink the red LED (Crossing LED / Battery LED).
  6. Testing features: The communication check button can be pressed an unlimited number of times. This allows you to accurately determine the optimal mounting location, check the passage of the radio signal through closed doors and other obstacles, and also adjust the location of the collector or sensor in case of uncertain reception.

12. Time synchronization

The correctness of hourly reports directly depends on the accuracy of the internal device clocks.

Time synchronization for S1 family sensors is performed completely automatically. During pairing and during each communication session, the gateway reads the exact network time (via NTP or from the server) and writes it to the connected sensors.

Important

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

13. Certification and standards compliance

SensMax sensors are manufactured in accordance with strict quality, safety, and environmental standards adopted in international markets:

  • CE (Conformité Européenne): Full compliance with the requirements of the European Union directives on electromagnetic compatibility, electrical safety, and radio frequency spectrum.
  • RoHS (Restriction of Hazardous Substances): Products are manufactured without the use of hazardous substances (lead, mercury, cadmium, etc.) in accordance with EU environmental directives.
  • GDPR Compliant: Sensors fully comply with the EU General Data Protection Regulation. They record exclusively quantitative anonymized statistics (number of IR beam crossings), do not collect personal data, do not use video cameras, and 100% preserve visitor privacy.

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 and SLR 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 S1 LR - 915 MHz). Equipment with different frequencies will not be able to communicate with each other.

Unidirectional sensors (batch transmission)

Model / Part Number Description Compatible collector
SensMax S1 Pro Wireless unidirectional counting sensor (up to 50 m) SensMax SMX PRO
SensMax S1 LR Wireless unidirectional counting sensor Long Range (up to 150 m) SensMax SMX LR
SensMax S1 SLR Wireless unidirectional counting sensor Super Long Range (up to 800 m) SensMax SMX SLR

Data collectors (gateways)

Model / Part Number Description Compatible sensors
SensMax SMX PRO Wireless data collector (Ethernet/Wi-Fi AP) SensMax S1 Pro
SensMax SMX LR Wireless data collector Long Range (Ethernet/Wi-Fi AP) SensMax S1 LR
SensMax SMX SLR Wireless data collector Super Long Range (Ethernet/Wi-Fi AP) SensMax S1 SLR

Accessories

Model / Part Number Description Compatible sensors
V-type swivel bracket Plastic swivel bracket (up to 180° horizontally) All S1 series sensors
L-type corner bracket 90-degree bracket for perpendicular mounting All S1 series sensors
Outdoor housing Sealed waterproof protective box (IP68) All S1 series sensors

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.