Hardware Overview; Detector Application Brief Explanation; Glass Break Detector Board Design Explanation - Renesas RL78/I1D User Manual

DETECT-IT RL78/I1D detector boards kit
1.

Hardware overview

The solution kit Detect it! includes 4 different types of detector demonstrator:
- Glass Break detector demonstrator
- Carbon Monoxide detector demonstrator (CO detector)
- Motion detector demonstrator
- Smoke detector demonstrator
The purpose of those boards is to show that the Renesas microcontroller RL78/I1D MCU - used in each board - is a
perfect device for implementing low power sensor designs for detectors with a minimum of external components. In
each case, the board shows a different detection using the RL78/I1D and its embedded analog peripherals such as
internal operational-amplifiers, comparators and optimized power saving MCU features. The new RL78/I1D has some
major advantages for detection against previous RL78 MCU families.
The Renesas MCU RL78/I1D has specific features that can benefit to such type of detectors/sensors, for example
usually requiring low power features like low average current drain and long battery life.
The RL78/I1D MCU has low power clock/timer and safety features in STOP mode that needs less than 1µA total, even
when Real-Time-Counter operated with 32kHz crystal, Watchdog timer operated with 15kHz clock, 12-bit interval
timer and Low Voltage Detect functions are all enabled, and all RAM data retained.
The RL78/I1D also has integrated operational amplifiers and comparators that can be used for sensor measurements at
low power. Current drain for the RL78/I1D integrated operational amplifiers and comparators depends on factors such
as external bias resistor values, which operational amplifier and comparator modes are used and how many channels are
enabled during standby. The integrated operational amplifiers of the RL78/I1D have both a low power mode and high
speed mode. In Low Power mode, the operational amplifier is typically drawing about 2.5µA typical for the first
channel (plus ~2.0µA per each additional channel) with GainBandWidth (GBW) = 40kHz. In High Speed mode, the
current draw is around 140µA typical for first channel (plus ~120µA per each additional channel) with GBW =
1.7MHz.
All boards have a different sensor depending on the measurement that needs to be done:
 Glass Break detector demonstrator use a microphone to detect noise that emulate glass break event.
 Carbon monoxide detector (CO detector) demonstrator uses a chemical sensor
 Motion detector demonstrator use a specific PIR sensor based on infrared technology to detect movement.
 Smoke detector demonstrator use a smoke chamber, with emitter and receptor diode
All boards are processing the measurement coming from these sensors with amplification and filtering stage done by the
microcontroller.
There is possibility to power each board by battery (3V lithium battery) or by power supply. All the detector boards
demonstrate a low current consumption. For the purpose of the demonstration, the goal was to achieve a battery life of 4
years or more using a CR123 lithium battery. Further optimization can be done in true application to minimize further
the current consumption of the board. Only one battery CR123 is provided into the kit for the 4 boards.
2.

Detector application brief explanation

Here are brief explanation of function of each board, including top level block diagram.

Glass Break detector board design explanation

The Glass Break detector is designed to start alarm when a glass break sound event occurred. By consequence the goal
is to start alert when high frequency sound is detected, and to filter all loud sounds such as loud hand clap, slamming
door, book slammed down on a table or barking dog. It was designed to detect simulated glass break event, such as
emulated by the Interlogix 5709C-W glass break simulator.
UM-YDETECT-IT-RL78 V1.30
Kit User Manual
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