Reference Design: Automatic Meter Reading - LFRD003
LFRD003: Water Meter Automatic Meter Reading (AMR) Reference Design
The MAX7032 transceiver reference design (RD) is a self-contained evaluation platform for exercising the device as a wireless automatic meter reading (AMR) and water meter demo system. With the use of the Maxim USB-to-JTAG board (MAXQJTAG-USB), the MAXQ610 on both the handheld interface (HHI) unit and the various meter (MTR) radio modules can be programmed by the end user.
The meter board enables basic human interaction through a single momentary switch input and an LED for visual feedback. The MTR is designed to be compact, providing a self-contained transceiver board with a radio, microcontroller, and multiple “ports” for connecting various meter inputs to the system. Two separate designs are provided: one with an MMCX antenna connection, and the other with a small-footprint antenna-mounting option. Input to the MTR system can be configured with up to six ports, and the primary input interfaces with a “pulse” or dry contact (reed) output meter. This board can be operated from any 3V power source (1.7V to 3.6V for the MAXQ610, 2.1V to 3.6V for the MAX7032).
The HHI board has seven menu keys for user input, a reset switch, a 102 pixel x 64 pixel LCD display with multicolor LED backlighting for menu interactions, plus a receive signal indicator (RSI) LED. The shape of the HHI fits within a Series 55 BOX enclosure, and has a high-density connector for interfacing with an RF module.
Both systems are preprogrammed with operational firmware to demonstrate a simple wireless AMR meter (slave)/reader (master) system. Gerber files are available for simple cut-and-paste designs of the radio sections or the full implementation.
- Proven printed circuit board (PCB) layout
- Proven component parts list
- Preprogrammed transceiver (TRX) pair for quick demonstration capabilities
- Free MAXQ® microcontroller programming tools available for flexible operation
The Handheld Interface (HHI)
The HHI is a two-part system that comprises a human interface board, which contains a LCD display, a key encoder, and a microcontroller. This HHI is mated to an RF module to form a complete handheld communication system. The Phase I design interfaces to a MAX7032 transceiver module through a 10-pin, high-density connector. The Phase III design and the RF modules described later interface through a 60-pin connector.
The HHI board provides a basic method of input with seven keys and one reset switch. This interface provides for flexible output through an Electronic Assembly DOGS102-6, 102 pixel x 64 pixel, transflective LCD display with a duo-color backlight. The board also contains an independent “signal” LED.
This system interfaces with the RF module through a board-to-board, mezzanine connector using a firmware-defined SPI. The MCU is programmed through an edge connector interface to USB. The power can be supplied through either the edge connector or a wired battery connection. The RF module has an MMCX connector, to which a 6” cable and a reduced-height Linx antenna may be attached, providing a small form factor assembly. The entire system has been designed to fit within a box enclosure, conveniently sized for handheld use (Figure 1).
Similar to the Phase I hardware, the Phase III HHI is a two-board system. The only changes in the HHI board between Phase I and Phase III is the use of a 60-pin hermaphroditic connector from Samtec in place of the 10-pin Hirose connector. This connector utilizes the same SPI communication lines between the microcontroller on the HHI and the microcontroller on the RF module. A few additional power lines are available in the larger connector but a majority of the additional signal pins are not used. This 60-pin connector is compatible with the Newport reference platform.
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