Panchromos focuses on the development of instruments intended for series production. By "instrument" I mean an integrated device that serves to provide a user (human operator, machine or system) with decision-support information on one or more physical parameters of interest. The information can be qualitative (detect) or quantitative (measure), or it can show the distribution of the parameter over space (imaging) and/or time (monitoring). In many cases that physical parameter relates to the presence of a chemical substance or biological species. Instruments combine mechanical, electronic, optical and chemical elements with (embedded) software - so a multi-disciplinary approach is needed. We tend not to work on one-off scientific instrumentation - although we'll often build single prototypes and models.

Instruments contain the following sub-functions:

Sensor

The element that translates the physical quantity into a signal that can be read. Although there are a lot of instruments that work without any electronics - think of a compass, thermometer, pressure gauge or film camera - for most new instruments the sensor outputs an electric signal. Most projects start with advances in sensor technology that hold the promise for a better (read cheaper, lighter, faster, more sensitive or robust) instrument. We have particular expertise with optical sensors: photodiodes, CMOS imagers etc. 

Conditioning

In many cases the instrument must create the conditions under which the sensor can operate - think of sample preparation, positioning the sample or sensor, heating/cooling, illumination. This function is often underestimated but regularly turns out to require more implementation effort then the main sensor - conditioning typically requires a mix of fluidics, optics, precision mechanics, thermodynamics and chemistry . The conditioning function can have its own sensors and control mechanisms.

Translation

Most current instruments contain programmable electronics which digitises the sensor signals, then translates them into the information of value to the user through the use of software algorithms. The higher the abstraction level of the information to be provided to the user, the more effort has to go into the translation function - just showing raw measurement data is easy, but when the instrument needs to show only a yes/no result the decision algorithms might need to be very sophisticated.

When the instrument is used to control a feedback loop this means translating the sensor signals into a form that the actuator can use.

Output

An instrument needs to provide the user (human, machine or system) with  some information on the physical parameter. For a human user this can be through a display, sound or touch. When the instrument is part of a larger system it tends to be a stream of data over some communications interface.

Control

Controls the operation of the device from outside the signal path (Sensor - Translation - Output). Can include user controls (buttons, touch screen, USB interface). In many but not all cases the same  embedded microcontroller handles the translation and the control functions. Many instruments also have mechanical or optical aspects of control - i.e. an imaging device needs to be manually focussed, or a reagent needs to be manually added. The way an instrument is controlled is crucially important to make it easy to use, especially for low-cost instruments used outside the lab by casual users (e.g. Point-of-Care or home-test diagnostics).

Power supply

All instruments containing electronics need to be powered. In most cases we'll use an off-the-shelf DC low voltage adapter ("brick" or "wall-wart") as this means the Low Voltage Directive is applicable. In some cases the instrument can be bus-powered - but bear in mind USB can only supply a maximum of 500mA at 5V. Instruments for portable use contain batteries - usually with internal charging circuitry. Other options include photovoltaic cells, and energy harvesting from mechanical movement or thermal gradients.

Case

Often undervalued, the right case is of critical importance to make the instrument robust and easy to use, again especially for instruments that are deployed outside of a laboratory setting. Where cases for high-volume instruments are usually made by injection moulding, this becomes prohibitively expensive for smaller series - where hot forming, PU moulding or additive production methods are better options.

The Sensor and Conditioning functions vary the most from one instrument to another, so these tend to be the focus of hardware design. Translation is usually done purely in software. The Output, Control and Support functions show less variation, and as these functions are present in almost all instruments; projects can be shortened by using platform designs - like our CHIP-1 for handheld instruments.

Cartridges and consumables

Have a look at my blog post on this subject here. Whatever your opinion, in many cases instruments have to be used with associated consumables. Consumables that are supplied as disposable cartridges are prefered for casual users and field use, whereas high-throughput users can reduce cost by using bulk consumables. In any case, we often need to design both instrument and consumable cartridges together.