Projects

Here is a list of projects to give you an idea of the variety of products we have developed for our customers. The list is in no particular order and not comprehensive. We design for production runs and bespoke equipment.

USB text message display

A compact device designed to be plugged in to a (headless) server to indicate provide indication of the status of the server. It replaced a previous device which used coloured LEDs to indicate status. The OLED text display provides a clearer message and circumvents concerns about colour blindness of the user.

Power and amplifier control system

A mains and battery powered controller using an STM32 and FreeRTOS to control power to peripherals and amplifiers. The unit can switch between battery and mains power. It uses I2C to interface with the smart batteries. Temperature sensors (also on I2C) are placed strategically over the board to monitor faults. A fan is set to automatically run at a specified speed to provide cooling if necessary. An SPI bus is used to communicate with the motherboard using Google's protocol buffers.

Water purity measurement

Circuit to measure the conductivity of water produced by a reverse osmosis machine and indicate that it is working correctly. Detection of circuit or connection failure to ensure correct function of the system.

Dialysate conductivity measurement

Used to measure the conductivity of solution used in a dialysis machine. Electrolytes are added to the solution using the conductivity measurement in a closed loop. Accurate temperature compensation is an integral part of the measurement system. Dedicated hardware using an STM32 micro and high speed ADC using an AC signal to measure the conductivity.

Hardware incorporates failure detection. Firmware written to comply with IEC62304 requirements for medical devices.

Thermocouple calibrator

Used to check and calibrate instruments that use thermocouples as their sensing element. The calibrator outputs a precise voltage from micro-volts to millionths with a setting for cold junction compensation. It simulates the popular types B,C,D,E,G,J,K,N,P,R,S,T following the standard curves in IPTS-68 and IPTS-90. As a calibrator this instrument offered exceptional precision, typically ten times better than the measuring instruments it was calibrating.

Air data test set

A very special piece of equipment which is used to check and calibrate the sensors used to measure altitude and airspeed in an aircraft. It requires very precise measurement and control of air pressures to simulate flying at a given speed and altitude. The user interface makes the task of checking the sensors as easy as possible. There are hardware and software guards in place to protect against malfunction damaging the delicate aircraft instruments, for example a user entering erroneous values or even a sudden, complete loss of power.

Humidity data logger

A small logger that will record the ambient humidity with the start time and logging interval programmed by the user. It can be left logging for up to 2 years (depending on the logging interval). When recovered the data is downloaded to a PC for analysis and storage. This compact logger fitted in an enclosure only 30x25x20mm.

Liquid flow rate recorder

Used to test and calibrate the flow rates of infusion pumps which are found in hospitals. This was a four channel device based on a previous design but incorporating cutting edge features for its time. It featured a GUI which could be controlled using a five buttons arranged like the navigation buttons which are the norm on mobile phones today. If you preferred using a keyboard a conventional PC keyboard could be plugged in too. The firmware was stored in FLASH and could be updated by the user.

Syringe pump recorder

Used to test and calibrate syringe pumps which can have exceptionally low flow rates which are difficult to measure. It measures the mechanical displacement of the plunger and is so sensitive it will show the stepper motors pulsing on and off as the pumps electronics modulates the power to achieve the set flow rate.

Gas flow analyser

The gas flow analyser allows hospital departments to check the flow rates of their anaesthetic machines. An electronic mass flow meter was used to measure the flow but compensation had to be applied according to the type of gas being measured. The analyser displays and records the flow rate and the total flow of the gas equipment under test. The gas flow analyser used FLASH memory for code storage and EEPROM for calibration and configuration. The graphics display was unable to show text and graphics simultaneously so two fonts – large and small - were created and stored in boot memory.

X-ray dosimeter

Using a carefully designed free air parallel plate ionisation chamber with a large surface area the dosimeter measures the levels of radiation that a patient would be exposed to during X-ray imaging. The unit features a wide dynamic range and a rapid response time to ensure accurate total dose measurement. The operator can switch between total dose and instantaneous dose and choose from a range of common units. The display used bright 1” high 7x5 dot matrix LEDs for easy reading and durability.

Audiometer

A low cost audiometer for use in third world nations developed after consulting with several clinicians and technicians. The audiometer generates precise levels of a standard tone for rapid screening of children. It was designed to operate in conditions of high temperature and humidity and powered by easily available batteries.

Gait logger

To help with research into diabetes the Orthopaedics department in a large teaching hospital developed special sensors which could be attached at a patients foot. We designed and produced a light weight, battery operated, hand held unit which could log the reading from eight sensors simultaneously. A diagnostic mode allowed the technician to check that all the sensors were working correctly. At the start of the test the unit would determine how many sensors were connected and log the readings. At the end of the session the data is downloaded to a PC in CSV format for analysis.

Intruder detection

A large multi-storey office block required a scalable alarm system to detect intruders using a mixture of passive infra-red sensors and switches. The activation and deactivation times could be programmed in for a seven day cycle. The system recorded any intrusions to non-volatile memory. An built-in thermal printer enabled the operators to print out the list. (Why thermal paper? To make maintenance easier, there were no ribbons or ink cartridges to change.) The sensors were on a network so they could be added and removed at will. The system automatically kept track of and recorded which sensors were available.