Tim W. Profile

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3.8

(1 review)

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$40 USD / hour

bloomfield,

united states

$40 USD / hour

It's currently 9:37 PM here

Joined July 10, 2015

0 Recommendations

Tim W.

@tjwoolaver

3.8

(1 review)

2.7

100%

$40 USD / hour

bloomfield,

united states

$40 USD / hour

100%

Jobs Completed

100%

On Budget

N/A

On Time

N/A

Repeat Hire Rate

Electrical Engineer

Electrical Engineer with 25+ years of experience in electrical engineering in the fields of motion control, embedded computing, electro-optics design and others. Holder of three US patents. 30+ CPLD designs. Designed dozens of PCBs from concept to production. Designed system architectures for several systems. Wrote software for embedded controllers on several platforms (ATMEL, PIC, 68000, 8085, 6805, TI DSPs). Supported designs from concept through production and regulatory approvals. Implemented processes to improve PCB manufacturing yields. Supported service engineers on technical issues. Managed projects and supervised technicians and other engineers in their execution.

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Portfolio

This design is an EEG system that uses a PIC184550 as the controller. Electrode amplifiers (round boards) are connected through a headset to an ADS1299 A/D system on chip, designed specifically for capturing EEG data colection. The EEG data is sent to an Android tablet via a BLE connection where the signal processing is done. It is a battery powered system with charging and low battery detection.

EEG system with Android Bluetooth Interface

This PCB is a component in a system that the client services. The
manufacturer no longer produces it and the documentation is unavailable.
The physical PCB was all that was available reproduce the board. The
client is providing it as a spare to the original manufacturer as well.

Magnetic Stirring Mechanism Controller

This design is a battery powered thermometer used to monitor temperatures of thawing food used by the health inspectors. There is a four-button user interface that runs the device and an LCD display for the menu selections, readings, and configuration.

The board uses an ATMEGA328 (The same microcontroller used on the Arduino UNO) as its controller. I also wrote the firmware for it and a diagnostic Windows interface in Visual Basic.

Temperature Monitor with Bluetooth and LCD display Interface

This design is a four-channel temperature monitor/controller for a commercial aviation application. The need arose from the fact that the temperature sensor previously used was no longer available. A new sensor was chosen but had different characteristics than the original sensor. Changing the firmware that used this data for the new sensor was not an option. The job of the board was to manipulate the analog signal from the new sensor and make it look like the signal from the old sensor from the aircrafts point of view.

The board uses an ATMEGA328 (The same microcontroller used on the Arduino UNO) as ots controller. I also wrote the firmware for it adn a diagnostic Wondows interface in Visual Basic.

Avionic Temperature Controller

This design is used in a collar which sprays disinfectant on the wearer (not my idea). The ESP32 controls and interfaces with the following::

Two Blowers
Temperature Sensor.
Pulse Oximeter
Bluetooth Interface to Android Devices
WIFI interfaces
USB Interfaces (USB UART Bridge
Piezoelectric Beeper
Battery Charging and monitoring
Flash

ESP32 Controller

This board is an Arduino shield with a DRV8825 stepper driver and a Bluetooth interface.

Stepper Motor Controller with Bluetooth Interface

EEG system with Android Bluetooth Interface

Magnetic Stirring Mechanism Controller

Temperature Monitor with Bluetooth and LCD display Interface

Avionic Temperature Controller

ESP32 Controller

Stepper Motor Controller with Bluetooth Interface

Reviews

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3.8

$222.00 USD

Stepper motor control board with Arduino

Worked well with this freelancer. Some delays in deliverables due to shipping hardware.

Electronics

Electrical Engineering

Arduino

Mark P.

@theiatech

•

9 years ago

Experience

Self Employed

Nov 2012 - Jul 2022 (9 years, 8 months)

Completed 50+ projects for various applications. Designed embedded system PCBs providing the following functions. WIFI, Bluetooth and non-standard FSK interfaces. LCD touchscreen displays. Actuators, Stepper Motors, Sensors and Servo Motors. Keypad and push button interfaces. Analog signal conditioning. Battery charging and monitoring. Wrote firmware for embedded controllers. Wrote GUIs in C# and VB to communicate with the embedded systems. See Design Examples.pdf in my portfolio for more.

Axsun Technologies

Jan 2010 - Nov 2012 (2 years, 10 months)

Designed a PCB using an the ADI Blackfin Microprocessor for a Fiber- optic Cardiac Catheter System. It is used by surgeon to control the catheter within the patient. It spins and drives the catheter while illuminating the artery and collecting image data. The PCB has the following sub-systems. A 3A Stepper Driver. A Brushless hall commutated motor driver. An RFID Reader/Writer. A keypad interface. Switching Regulators . See Design Examples.pdf on my portfoleo for more

Seahorse BioScience

Feb 2007 - Jan 2010 (2 years, 11 months)

Seahorse BioScience designs and manufactures extracellular flux analyzers used for in-vitro assays. Using LEDs, fiber-optics and fluorescent probes, oxygen consumption rates and acidification rates are measured in live cells. Designed a PIC based temperature controller PCB. Designed and built test fixtures for all of the PCBs in the system. Wrote Test Procedures. Debugged EMC, EMI, and safety problems. See Design Examples.pdf in my portfolio for more design examples and qualifications.

Education

Bachelor of Science in Electrical Engineering Technology

Northeastern University,

United States

1980 - 1986

(6 years)

Publications

System method and product for pixel clocking in scanning biological materials

US Patent Patent number: 6650411

Systems and methods are described that may be applied to scanning biological materials in or on probe arrays. For example, a system is described that includes a scanner that has one or more excitation sources and an emission receiving element, such as an objective lens, that receives from locations of the probe array an emission signal responsive to the excitation sources. The scanner also has a radial position generator that generates radial positions of the emission receiving element.

High throughput microarray spotting system and method

US Patent Patent number: 7314595

A system is described for automatic retrieval of microplates from a carousel. The system includes an effector arm that retrieves a selected microplate from the carousel, a microplate retainer that receives the selected microplate from the effector arm, and a controller that directs the effector arm to the carousel for retrieval of the selected microplate and directs the effector arm to the microplate retainer so that it may receive the selected microplate.

System method and product for reducing dynamic fluorescence noise in scanning biological materials

US Patent Patent number: 7222025

Systems and methods are described for processing an emission signal, such as a fluorescent signal, to compensate for noise in an excitation beam, such as a laser beam.