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$30 USD / hour
Flag of UNITED KINGDOM
$30 USD / hour
It's currently 12:17 AM here
Joined July 17, 2011
5 Recommendations

David L.

@Davelelievre

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4.9 (31 reviews)
6.4
6.4
$30 USD / hour
Flag of UNITED KINGDOM
$30 USD / hour
100%
Jobs Completed
100%
On Budget
100%
On Time
2%
Repeat Hire Rate

Electronic Design Engineer

Electronic Design Now offers a complete electronic systems design and consultancy service. With small overheads I can impart a professional personal flexible service to deliver a quality reliable product at low design costs. I encompass the knowledge and resources to implement the following tasks in an innovative and imaginative way:- Digital Design I have had vast experience in designing high speed digital electronics, microprocessor based products and gate arrays. One recent example is the design of a new Digital Multimeter with a PCI interface. Analogue Design I have been actively involved recently in providing stimulus and measurement signals between a functional test system and a target device under test. These signals have ranged from low level micro volts to hundreds of volts. I have also designed the high voltage interface on DTR cable test systems. Analogue design always presents a challenge, especially when mixed with "noisy" digital electronics. However I am very adapt at this task, having seen this situation many times before. PCB layout I have all the design software to produce schematic diagrams and PCB layout for complex electronic assemblies. I have performed the PCB layout on nearly all of my designs. I believe the design engineer is always the best person to implement the layout as only he has the insight and knowledge to determine the optimal part and track placement together with all the other parameters such as power planes and shields. Product Specification and Reports Having worked within an environment supplying electronic equipment to the military and blue chip companies I have a vast experience in writing engineering and marketing specifications, test schedules and strategies, evaluation studies and detailed product reports. Again I am always methodical and structured in my approach to this task. EMC Compliance Consultancy Having designed many products that have had to be CE tested or EMC compliant to a tight military specification, I am well placed to advise on any new system development. I can ensure that new products have an excellent chance of achieving EMC Compliance at first trials without endless modifications at a late stage in the development. Reverse Engineering From your old obsolete PCB where all the original design data may have been lost, I can generate the following:- New schematic diagram New PCB fabrication New items list containing all RoHS compliant components Eliminate any component that have become obsolete or are not compliant. Data sheets for all new components Test & Manufacture - Strong links with local companies to provide a full procurement, manufacture and test service. Software Development Although not trained as a software engineer, I have got the knowledge and expertise to provide test and evaluation software for all products that I design. Furthermore in some cases I can provide the actual finished application software. For example I fully developed my Race Management software (see Design History), that is extremely comprehensive and packed with innovative features. If necessary however, I have partners that I can use to provide a full capability. Interface Design - PCI, USB, Wireless, RS232, RS485, I2C, VXI, VME Full System Design and Support For a new system design I can provide a total turnkey solution from concept to a fully tested and evaluated developed product. I am extremely methodical and organised in my approach and can arrange everything from component specification and procurement, right up to volume manufacture. I have a flair for electronic innovation with a proven track record of successful products. I have worked on numerous projects throughout my career, here are a few examples:- Self Contained Rugged design Test System entitled "minFLITS" This consisted of a rugged laptop fitted with an underneath instrument bay. The instrument bay allowed up to four PMC (PCI mezzanine card) instrument / measurement modules to be fitted within a rugged temperature controlled environment. I was responsible for the complete hardware design of this instrument bay except for the mechanical case. That is the electronic intelligent PCI backplane and all hardware interfaces between the laptop, instruments and the outside world. The resource backplane even allowed for "Hot" switching of the PMC instruments to conserve power and limit unnecessary heating when they were not in use. Digital Multimeter This full featured module was designed very recently on a PMC format to be fitted within the instrument bay of the miniFLITS described above. The module contained an onboard intelligent 16bit ADC with built in filtering. It could measure voltages up to 100 volts (DC and True RMS) and resistances to 100 Megohms with ranges and accuracy comparable to the National Instruments NI4050 PCMCIA card. This module with its size and low power consumption is ideal for portable measurements and data logging on laptop computers. I wrote the full test and evaluation software in VB6. This product was developed on a tight timescale and I achieved conception to working prototype in three months. The idea and design architecture was again all my own. Interface to the Flight Control Computer on a Lynx Helicopter I designed the electronic interface between this Flight Control Computer and the miniFLITS Instruments. The interface consisted of relays, solid state multiplexers, buffers and signal conditioning electronics. It also contained a phase lock loop to enabled precise phase, fequency and amplitude control of the AC stimulus signals. Slot Master Race Management System The Slot Master is a race management system designed to control and time scalextric and other slot car events. Its unique features are that it uses either a USB or PCI port and therefore is fully compatible with modern PC's and laptops. Besides normal lap counting and timing to 1/1000 second it is able to measure the throttle voltage for use in instant false start detection, fuel management and performance graphs. I pioneered some unique features with this software that have only recently just been copied. The windows software was written in VB6 and the firmware for the USB interface was written in C. This system was fully conceived and designed by myself and I have sold over 160 systems world wide. Distributed backplane and cable harness test system This test system was conceived by myself and provides a unique way of interfacing to multipoint test targets such as backplanes. The test system consists of high pin count intelligent test cards distributed around the target and connected by a 14way daisy chain ribbon cable. This avoids large and unmanageable cable looms that are very prone to damage. Again this system is very innovative with only one other of its kind sold in the world. High Voltage cable harness test system I was a former director of DTR Systems that designed and manufactured these testers. Although I have now sold the company, I am still closely involved and continue to provide a full design and support service. I was solely responsible for the full hardware and system design of this product family with the software written by another company director. The system is capable of measuring Gig ohm resistances at 1000 Volts down to milliohm values at 1 Amp. The tester also supports some unique functional features such as remote control of vibration and environmental chambers. These testers have been sold into some major blue chip companies such as BAE, IBM, Goodrich and just recently Rolls Royce. Torque Measurement System Design, development and product introduction of a stand alone torque measurement system used by the MOD to measure engine performance on a Lynx helicopter. The product was a stand alone microprocessor based system with its own display. All aspects of the product was designed by myself except for the firmware. Gas Detection I designed an eight channel gas detection system for the gas division of Blakell Ltd. I was responsible for the system, electronic and firmware aspects of this product with only the PC windows software written by someone else. The microprocessor based system could be used as a stand alone detection product, with its own alarms and warnings, or linked to a PC for data logging and remote control. Schlumberger/ Factron Series 7700 Test Systems I led a small team of people to design and develop the in-circuit capability on this platform of testers. The tester was extremely successful and achieved many sales back in the 1980's The following is a link to a patent I hold on the digital in-circuit architecture for these systems [login to view URL]
Freelancer Electronics Engineers United Kingdom

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Portfolio Items

Circuit design and PCB Layout. The device was based around the Analogue devices AD8232 and the Nordic transmitter NRF5001
The device was fitted within the case shown and fitted to a chest strap
BlueTooth ECG Monitor
The Slot Master is a race management system designed to control and time scalextric and other slot car events. Its unique features are that it uses either a USB or PCI port and therefore is fully compatible with modern PC's and laptops. Besides normal lap counting and timing to 1/1000 second it is able to measure the throttle voltage for use in instant false start detection, fuel management and performance graphs. I pioneered some unique features with this software that have only recently just been copied.
The windows software was written in VB6 and the firmware for the USB interface was written in C.
This system was fully conceived and designed by myself and I have sold over 160 systems world wide. 

A full description of this product can be found at www.slotmaster.com
Slot Master Race Management System
This consisted of a rugged laptop fitted with an underneath instrument bay. The instrument bay allowed up to four PMC (PCI mezzanine card)  instrument / measurement modules to be fitted within a rugged temperature controlled environment.
I was responsible for the complete hardware design of this instrument bay except for the mechanical case. That is the electronic intelligent PCI backplane and all hardware interfaces between the laptop, instruments and the outside world. The resource backplane even allowed for "Hot" switching of the PMC instruments to conserve power and limit unnecessary heating when they were not in use.
Self Contained Rugged design Test System
I was a former director of DTR Systems that designed and manufactured these testers. Although I have now sold the company, I am still closely involved and continue to provide a full design and support service. I was solely responsible for the full hardware and system design of this product family with the software written by another company director. The system is capable of measuring Gig ohm resistances at 1000 Volts down to milliohm values at 1 Amp. The tester also supports some unique functional features such as remote control of vibration and environmental chambers. These testers have been sold into some major blue chip companies such as BAE, IBM, Goodrich and just recently Rolls Royce.
High Voltage cable harness test system
I designed the electronic interface between this Flight Control Computer and the miniFLITS Instruments. The interface consisted of relays, solid state multiplexers, buffers and signal conditioning electronics. It also contained a phase lock loop to enabled precise phase, fequency and amplitude control of the AC stimulus signals.
Interface to the Flight Control Computer on a Lynx Helicopte

Reviews

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Showing 1 - 5 out of 31 reviews
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5.0
€40.00 EUR
Very gentle and fast solution!
Electronics Electrical Engineering Circuit Design Analog Electronics
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Flag of Francisco Herliczka H. @fhyeo77
9 days ago
5.0
£60.00 GBP
Dave's experience helped us reach the goal. He proposed components and help troubleshoot and build the circuit with limited knowledge on my side. Thanks Dave!
Electronics Electrical Engineering PCB Layout
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Flag of James R. @jrob19
7 months ago
5.0
[SEALED]
David is excellent. I have never had a more positive experience with a freelancer. He was thorough and maintained excellent communication with me the entire time, and he cares as much about my project as I do. He provided all the expertise I needed, and helped me build my product. A+, I can't recommend highly enough.
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Flag of Tyler S. @tylersuard
1 year ago
5.0
$275.00 USD
Amazing experience! Dave is incredibly knowledgable and helpful. Will definitely like to work with him in future.
CAD/CAM Electrical Engineering Arduino Digital Design
+1 more
C
Flag of Roy H. @cfza
2 years ago
5.0
$150.00 USD
I hired David to design a 4-20ma converter. He did it in a timely manner on budget.
Electronics Microcontroller Electrical Engineering PCB Layout Circuit Design
G
Flag of Gary M. @garymus
2 years ago

Experience

Principle Electronic Design Engineer

EADS Test & Services
Jul 2003 - Sep 2010 (7 years, 2 months)
Responsible for system and PCB design of new automated test equipment (ATE) products. one example was the design and development of a digital multimeter PMC instrument card

Principle Electronic Design Engineer

Blakell
May 1987 - Jul 2003 (16 years, 2 months)
Responsible for the design and development of new ATE products. One example was the complete design and introduction of a high voltage cable test system

Project Manager

SCHLUMBERGER LTD
Jul 1982 - May 1987 (4 years, 10 months)
Project management of a small team of engineers to design a digital in-circuit test facility within an automated test system .

Education

First Class Honours Bsc

1972 - 1975
(3 years)

Publications

Digital In-Circuit Architecture

Patent
The following is a link to a patent I hold on the digital in-circuit architecture for these systems http://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=0&adjacent=true&locale=en_GB&FT=D&date=19850619&CC=EP&NR=0145194A1&KC=A1

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Top Skills

Electronics 31 PCB Layout 21 Electrical Engineering 19 Microcontroller 10 Circuit Design 10

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