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automatic fare collection (AFC)
Designed several high-power infrared and visible LED pulsed flash illuminators for outdoor photo capture used in transportation monitoring systems. The design features stuck-on LED protection, low average power consumption, handles peak surge currents of 100A, and has an adjustable radiation pattern.
Designed a pair of optical sensor cards (transmit and receive) for sensing coins falling through a return chute. Featuring closed-loop feedback for self-adjustment of optical output to compensate for aging, dirt build up and extend the life of components. Involved collaborative electronic circuit design, schematics, printed circuit card (PCB) layout, cabling, harness, interconnects, test and integration.
Developed an over discharge protection circuit and a constant current/voltage pulse width modulated 3A battery charger for a sealed lead acid battery back up. And integrated it into a microcontroller based alarm module. Involved electronic circuit design, collaborative electronic circuit design, schematics, test and integration.
Designed a card to replace an obsolete 50 Volt bi-polar full bridge motor driver. Featuring discrete power Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) controlled by programmable logic with current sense control inputs for over current protection, and a very compact 1.25-inch by .6-inch printed circuit card (PCB) layout. Involved electronic circuit design, schematics, printed circuit card (PCB) layout, firmware, test and integration.
Designed a card for controlling movement in a ticket transport mechanism. Included motor drivers, solenoid drivers, and optical sensor inputs. Involved collaborative electronic circuit design, schematics, printed circuit card (PCB) layout, cabling, harness, interconnects, test and integration.
Designed four cards for various automatic fare collection (AFC) machines including a card that processed turnstile gate sensor inputs using a 32 bit microcontroller, and 24 Volt optically isolated inputs; a power distribution card for gates; a power failure monitor; and redesigned a solenoid and sensor interface card. Involved collaborative electronic circuit design, schematics, printed circuit card (PCB) layout, test and integration.
Designed I/O expansion cards for an automatic ticket vending machine (AVM). Featuring computer controlled voice output, audio amplifiers, cascaded Direct Audio Storage Technology (DAST) or a speech synthesizer, programmable logic, and multiple serial channels. Involved collaborative electronic circuit design, schematics, printed circuit card (PCB) layout, test and integration.
Redesigned a magnetic stripe ticket reader interface card for an automatic ticket vending machine (AVM) and designed a microcontroller based hopper security module. Involved collaborative electronic circuit design, schematics and printed circuit card (PCB) layout.
Designed seven cards for various automatic fare collection (AFC) machines including a switch interface; a UPS interface that sends a power fail signal from an uninterruptible power supply to a serial port; an aisle sensor pulse modulator/driver; a serial adapter for a voice module; extender cards for maintenance; and a smart card target interface. Involved schematics and printed circuit card (PCB) layout.
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