Infrared Human Sensor Reference Design

By Renesas Electronics America 140

Infrared Human Sensor Reference Design

As a part of their Quick Solutions, Renesas has created a reference design for a human infrared sensor that detects human absence/presence by utilizing a high brightness LED that can turn on and off automatically. The infrared LED sending signal is controlled by Renesas' RL78/G10 MCU's timer array unit (TAU01), and the receiving signal is controlled by the external interrupt terminal (INTP0) and timer array unit (TAU00). The high brightness LED will turn on when a person is detected, and off when the person leaves the area after 10 seconds, the LED will turn off, and the system will enter an infrared receiving signal STOP mode. RL78/G10 offers the lowest current consumption in the industry today and is ideal for human sensing.

  • Minimum instruction execution time: can be changed from high speed (0.05 μs at 20 MHz operation with high-speed on-chip oscillator) to low speed (1.0 μs at 1 MHz operation)
  • General-purpose registers: 8-bit register × 8
  • ROM: 1 kB to 4 kB
  • RAM: 128 B to 512 B
  • Selectable high-speed on-chip oscillator clock: 20 MHz, 10 MHz, 5 MHz, 2.5 MHz, and 1.25 MHz (typ.)
  • On-chip single power supply Flash memory
  • On-chip debug function
  • On-chip selectable power-on-reset (SPOR) circuit
  • On-chip watchdog timer (operable with the dedicated low-speed on-chip oscillator)
  • On-chip key interrupt function: six key interrupt input pins
  • On-chip clock output/buzzer output controller
  • On-chip BCD (binary-coded decimal) correction circuit
  • I/O ports: 8
  • Timer:
    • 8/16-bit: 2 channels
  • Serial interface
    • CSI: 1 channel
    • UART: 1 channel
    • Simplified I²C communication: 1 channel
  • 8/10-bit resolution A/D converter: 4 channels
  • Standby function: HALT or STOP mode
  • Power supply voltage: VDD = 2.0 V to 5.5 V
  • Operating ambient temperature: TA = -40°C to +85°C


  • Infrared Human Sensor Reference Design
  • Infrared Human Sensor BOM