Projects

Feasibility Study for Battery-Powered 1 Mbps, 220 Channel Wireless Data-Streaming System for General Dynamics - Electric Boat

Summary: The client requested a feasibility study and system architecture recommendation for a system that must stream data from 220 individual wireless nodes at approximately 1 Mbps while providing long life from system batteries. A flexible architecture capable of expansion to other lower data rate channels was also desired. The work included the development of a comprehensive tradeoff analysis that considered modulation methods, system bandwidth, antenna diversity methods and node power consumption. Practical transceiver implementation issues were also addressed, such as transceiver device availability, device current consumption and PA non-linearity. Detailed link budgets were prepared using channel characterization data acquired during a prior project phase (described below). Practical system architectures were proposed for the wireless node and the system basestation, given costs and size constraints for both components. An IF-Sampling basestation receiver architecture was proposed and a preliminary building-block level design was completed such that a cascade analysis could be produced.

Hardware Design for Battery Powered Wireless Event Status Monitoring System for General Dynamics - Electric Boat

Summary: The client requested a prototype design of battery powered wireless nodes suitable for periodic transmission of system event alerts. The system was designed for ultra-low quiescent power consumption and efficient operation across a range of system modes. The system communicated using UHF FSK wireless transceiver chip, programmed for operation in the mid-UHF region. The transceiver was integrated into a small removable module that plugged into the carrier / microcontroller PCB. A custom DDRR (Directional Discontinuity Ring Radiator) antenna design was included, tuned for the customer's band of operation. The DDRR antenna design was provided by 360 Degree antenna in NY. Eighteen prototypes PCB sets were assembled & tested and submitted as part of the deliverable package.

Wireless Channel Characterization Procedure and Data Analysis for General Dynamics - Electric Boat

Summary: The client requested a test procedure for data collection and data analysis to determine the path-loss characteristics of UHF radio links operating in the customer's environment. The environment is highly reflective with limited line-of-sight. Multi-path reflection components and shadowing were also present, causing fades in certain locations. A key requirement of the test was to ensure that these regions were found and characterized to help understand operational placement and configuration of transmitters. The measurement procedure was written such that the customer could perform the measurements and submit the resulting data to us for post-processing. The data was analyzed to determine typical (mean) path loss and fading statistics all vs frequency and distance.

Phase 2, 12-Channel Automated Training Apparatus - Custom machine vision & control system for the Levin Labs at Tufts University

Summary: The system is used to track the motion of small organisms like tadpoles, worms & zebrafish in a small petri dish, and provide control of petri-dish illumination and small amounts of electric shock. The system allows the researchers to perform experimentation on organism learning & behavior mechanisms. The system includes 12 channels of machine vision, LED illumination and electric shock. Each channel is assigned to monitor and control one individual petri-dish.

The Cognex Insight Micro 1400 machine vision camera is used for each channel of image processing. The Insight Micro 1400 includes an internal DSP where all image processing algorithms are stored and executed. The image processing sequence contains an intelligent, self-healing background subtraction algorithm, various linear and morphological filtering operations and blob detection. After the image processing operations are completed, the Insight Micro reports back organism blob coordinates and other metrics such as blob area.

The system is controlled by an ARM9 MCU which is connected to the 12 machine vision cameras using TCP/IP over ethernet and 12 channels of shock & illumination using RS-485. Each illumination and shock channel contains an STM32F103 ARM Cortex MCU as the RS-485 network interface and a NXP LP2103 ARM7 as the excitation controller. Each illumination channel includes four 1.5 Watt, high-brightness blue LEDs and four 0.2W red LEDs. A 4-channel, 1A high-speed linear current source was designed and implemented to drive the high-intensity blue LEDs.

To meet a stringent 50,000 hr operational life requirement, the LEDs are mounted on a metal-core PCB for low thermal resistance at the fan-sink interface. In addition, each high-brightness blue LED is paired with a high-linearity light sensor, and the excitation controller provides feedback control of the drive current to compensate for LED brightness degradation over time.

Mechanical engineering and design of the system structure was performed by Owl Engineering of Medford MA. More information about Owl Engineering can be found at: owleng.vh.primushost.com

RF Transmitter / Receiver Test PCB for ASK Link - Custom RF test system for Wayne-Dalton, a garage door opener manufacturer.

Summary: The system is used to test the RKE (remote keyless entry) wireless link operation as part of a larger highly accelerated stress testing (HASS) system. The HASS system tests the electrical controls and electromechanical drive of the customer's OP40XR garage door operator assembly. The larger HASS system was designed by our strategic partner, Electromechanica, Inc., and the system is now part of Wayne-Dalton's production test process.

More information about Electromechanica, Inc. can be found at: www.electromechanica.com

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The image below shows the TRXD PCB. The transmit section is on the left and the receive section is on the right. Each RF section has it's own 32 dB high-accuracy digital attenuator. The microprocessor and system interface is in the center. Click the image to see a larger view.

Phase 1 Single Channel Automated Training Apparatus - Custom machine vision & control system for the Levin Labs at Tufts University

Summary: The system is used to track the motion of small organisms like tadpoles, worms & zebrafish and provide control of petri-dish illumination. The system allows the researchers to perform experimentation on organism learning & behavior mechanisms. The system uses an RS-170 analog video camera and BlackFin BF533 DSP to perform image processing and determine the organism centroid coordinates.