Applications
Building automation
People counting
Lighting control
Presence sensing
Gestures
Introduction
The future of smart connected devices is bright; however, many of the distinct
applications are unclear and waiting to be invented. Clearly, critical components of IoT
applications will ensure the safety of people and buildings, movement of commerce, and
activation of features. For these reason, MAXREFDES131# is the future of IoT. This
unique system marries a high-performance passive IR-sensing array, Panasonic’s Grid-
EYE, with Maxim’s 1-Wire bus, for enhanced range and simple interface.
MAXREFDES131# integrates the DS28E17 1-Wire-to-I2C master bridge with the
AMG8833 Grid-EYE sensor from Panasonic electronic components. This architecture
allows the sensor to be placed up to 100m from the host processor, on the 1-Wire bus.
The DS2413 1-Wire dual-channel addressable switch along with the MAX4717 dual-
SPDT analog switch allow enumeration of units on the 1-Wire bus. In addition, all units
can be put to sleep, or individually selected once enumerated, reducing power
consumption.
Example source code for interfacing with MAXREFDES131# has been developed for
both mbed and Arduino platforms. A demonstration GUI has also been developed
allowing for visual feedback of up to 10 daisy-chained MAXREFDES131# 1-Wire Grid-
EYE sensors.
Detailed Description of Hardware
Figure 1 provides a block diagram of MAXREFDES131#.
The design features two RJ-11 jacks, H1 and H2, for interfacing to the hardware and
daisy chaining units together. At power up, the MAX4717 comes up with COM1
disconnected from the 1-Wire bus and COM2 connected allowing the host to see the
first DS28E17 on the bus.
The DS2413 allows the host to connect/disconnect downstream units of daisy-chained
MAXREFDES131# units. In addition, the DS2413 channel controlling the connection of
COM2 to the 1-Wire bus also puts the DS28E17 to sleep when COM2 is disconnected
from the 1-Wire bus. When the DS28E17 is put to sleep, it disconnects power from the
AMG8833 reducing the current consumption of a single MAXREFDES131 from ~8mA to
~0.5mA. The I2C bus of the DS28E17 1-Wire-to-I2C master is also connected to H2 of
each MAXREFDES131#.
