Design-In-Expertise And Service
Search for ...
Manufacturer Category Article Free text

Holtek – BM32S2021-1 IR Proximity Sensor Module (for Object Detection)

BM32S2021-1 IR Annäherungssensor-Modul

BM32S2021-1 is an infrared proximity sensor module based on Holtek’s Proximity Sensing MCU BS45F3232. Besides the ASSP-IC it integrates an infrared emitter diode and an infrared receiver module. Additionally, it has a red indicator LED, to show the sensor’s status.

The modular design really shortens your development time and makes fast time-to-market possible.





How does this sensor module works?


The BM32S2021-1 is emitting infrared pulses in adjustable intervals and measures the reflected infrared via its IR receiver. If an object is at a certain distance in front of the sensor, the reflected energy of the infrared is changing and the object can be detected. To detect objects within distances of 1 to 100cm the IR emission current can be adjusted in several steps. For determing the sensing status a threshold value is used. It is either available via an I/O pin or via the UART interface since these interfaces share the same hardware pins.




A detection distance learning function is offered by the sensor module. By means of this function the sensor automatically adjusts itself for a certain scenario. The object to be detected is placed in front of the sensor at the desired distance, then the module automatically determines parameters such as trigger threshold and IR emission current storing them in its non-volatile registers. By this the sensor always reacts after the learning procedure the same way to corresponding objects. This automatic process significantly simplifies adjustment of the sensor for applications with unchanged scenarios.

Applications for BM32S2021-1

It’s detection distance and features make this sensor module perfectly suitable for applications like smart makeup mirrors, smart sanitary ware like water tap or soap dispenser. Even smart door locks are relevant applications.

But the sensor can be set and read out manually via the UART interface and its corresponding commands. By this, applications with dynamic requirements are no problem to be realized and the module can be used flexible in a lot more scenarios.

Features Overview

  • Operating Voltage: 3.3V / 5V
  • Current consumption (mean value):
    • 5mA typ. (3.3V / object detected at 85cm / scanning interval = 0.5s)
    • 14μA typ. Standby (3.3V / no object detected / scanning interval = 0.5s)
  • Detection distance: 1 to 100cm
  • Dimensions (L x W x H): 17.5 x 10.1 x 7.1 mm
  • I/O or UART Mode
  • Detection distance learning function
  • Adjustable parameters:
    • IR LED Peak emission current
    • Scaning interval
    • Trigger Debouncing (Noise Filter)
    • Trigger Threshold
    • I/O Mode
  • Product homepage

Are you looking for a proximity sensor that can be easily and quickly integrated into your product? Get in contact with us about Holtek’s solutions and evaluation environment:

    Please contact me by

    I'm intressted in: