1. A portable medical diagnostic device that consists of:

  • • Test cartridge uses novel biosensors and is designed for a finger prick or whole blood sample.
  • • Handheld reader takes the signal from the cartridge and interprets it as a numerical value. The reader also has considerable data processing capacity.

2. A 3D Printed and Injection Moulded Colorimeter

A colorimeter for measuring nutrients in aquaria was designed and constructed by a combination of injection moulding and 3D printing. The heart of the instrument was an injection moulded diffraction grating-based spectrograph consisting of a combined moulded plano-convex spherical lens with a 300 lines mm−1 diffraction grating impressed on the flat side of the lens. This was coated in aluminium in a vacuum deposition system to reflect light onto a 128 pixel linear CMOS image sensor.The entrance slit of the spectrograph was also moulded in black polystyrene. The spectrograph and image sensor board was enclosed in a 3D printed case. A white LED in parallel with a 420 nm LED were used as the light source, covering the range 410 to 700 nm.

The image sensor board was controlled by a PIC16F1788 8-bit microcontroller. Image data from the linear sensor was passed to a 12-bit ADC on the PIC microcontroller and was then passed back over a USB2.0 interface to a program written in C++ running on a PC for conversion to CIE chromaticity coordinates.

Main board of the colorimeter showing the PIC microcontroller in the centre.

The lens/grating mounted in its injection moulded holder and calibration curve for nitrate in the range 0 to 100 ppm. Error bars are ±1 standard deviation.

3. Value Engineering – Diabetes Care SMBG Market (Self-Monitoring of Blood Glucose)

One of the world’s leading medical device companies identified the Asia-Pacific region where we could bring significant benefit to patients.

  • • At the time, the countries with the largest number of people with diabetes were India (40.9 million) and China (39.8 million).
  • • SMBG market penetration was 5% and 3 readings/month in Asia Pacific vs 86% and 1.5 readings/day in US.
  • • The perception of affordability and ease of use were the biggest barriers to doctors pushing for the device.
The region identified an opportunity to involve key healthcare professionals in product definition and design – an excellent application of clear VOC (voice of the customer) prior to the design stage.

Key efforts were undertaken to re-engineer and de-spec current product offerings to achieve a lower manufacturing cost and hence reduce price.

The marketing strategy demonstrated the benefits of tight glycemic control through SMBG to the primary care physician and the endocrinologist, and convinced patients to ask their healthcare professionals about proper diabetes care.

The value-engineered SMBG device incorporated:

  • • Good industrial design
  • • Simple user interface – single button operation
  • • Low cost to achieve target selling price
  • • No built-in memory in the entry device – only the last result is shown
  • • No downloadable data
  • • Non-replaceable battery


  • • From the initial patient and environment scan to first product launch in India took 1-1/2 years
  • • Over the following 12 months, the product was launched in 13 additional countries.
  • • Over the following six months, the product was launched in six additional countries.
  • • One year after launch, launch metrics exceeded the forecast by a significant amount.
  • • The product generated 18% of total India sales within six months.
  • • In three years, the category grew in India from 30,000 devices to more than one million.

This illustrates the importance of involving key healthcare professionals across the region throughout the project, and laid the important groundwork for many more advanced follow-on products.

4. 3D printed Instrumentation

Using a conventional fused filament 3D printer, three instruments were constructed. First was an instrument for reading an optical biosensor1, the second an autosampler2 for sequential access to samples into the biosensor instrument and the third a stepper motor-driven multichannel peristaltic pump to transfer samples from the autosampler to the biosensor instrument. The critical parts of the optical biosensor instrument were printed in carbon fibre-filled polylactic acid (PLA) for rigidity, while the biosensor instrument case, autosampler and peristaltic pump were printed in unfilled black PLA. Both instruments had custom control board, the biosensor instrument using an XMOS microcontroller for its excellent real-time scheduling capabilities while the autosampler used an ARM microcontroller for ST Microelectronics.

The biosensor instrument used the XMOS microcontroller to rotate a mirror to direct light on to a 5Mpixel camera (2560 by 1920 pixel resolution). Image data from the camera was transferred to a PC using a USB2.0 high speed interface. The camera also passed data to the XMOS microcontroller via an I2C interface to control the mirror rotation, the camera horizontal movement, the sensor temperature (using a Peltier module) and the intensity of the light source used to illuminate the sensor chip.

The autosampler has four sampling needles that could be independently rotated to different sample vials, while all the sampling needles could be moved collectively up and down to insert the needles into the sample vials and retract them to allow movement to different vials. The autosampler could also control an external peristaltic pump, either a Gilson Minipuls or the 3D printed version.

5. Handheld multichannel potentiostat

A small PCB (102 by 62.5 mm) was designed to use an ARM microcontroller from ST Microelectronics with three on-board 12-bit digital-to-analogue converters and three 16-bit sigma-delta analogue-to-digital converters. These were used to supply the working electrode potential and monitor the cell current for three potentiostat channels. The board could run a 2.8” LCD display with touchscreen and communicate via USB, WiFi or Bluetooth. Cell currents could be measured down to a few picoamps.