ReadMe First.

The Piccolo3 is a novel lightweight multi-optical bench dual-field-of-view (DFOV) spectrometer control and fore optic system which can be provided with spectrometer modules with application-specific spectral and radiometric resolutions. These systems can be used for passive optical Earth observation (EO) and remote sensing research in natural or built environments, but particularly for use under skylight. It comprises of a weatherproofed and spiral stainless steel reinforced double bifurcated fibre optic cable assembly up to 7 metres long with low OH optical fibres. The fibre optic cable assemblies are bespoke and manufactured by Alker Optical Fibre Ltd, UK for TeamPiccolo. There are a custom custom designed weatherproof fore optic assemblies, one with bare fibre with approx. 25 deg field-of-view which can be constrained by a ‘gershun’ tube and the other with a ‘true’ cosine corrected hemispherical field-of-view with no wavelength dependencies. These are designed to accept upwelling and downwelling incident light respectively. They are designed for TeamPiccolo by Peak Designs Ltd, UK, each fore optic assembly has an internal bi-stable shutter and desiccant block. The fibre assembly is designed to attached to fibre optic input SMA connected OEM spectrometer modules, normally provided with the Piccolo system to match user requirements. The system is then controlled by a Piccolo3 shutter driver electronic  mounted on a Raspberry Pi 3 micro-computer with wifi and Ethernet connectivity.

Figure 1 Schematic of Piccolo with 1 spectrometer module

Figure 2 Schematic of Piccolo DFOV system with 2 spectrometer modules

A micro SD card is included with Linux/Raspbian operating system and python3 open source software installed for controlling the spectrometer system. The software is open source no charge has been made for its inclusion. Piccolo owners are free to modify and adapt the software to their own requirements. However, if the software is modified from the standard installation provided, or from that installed by the supplier in routine updates, the supplier will no longer be able to continue to offer software support.

Figure 3 Schematic of piccolo2 dual bifurcated fibre optic assembly adopted to maximise light throughput.

Note The fibre optic assembly shown in Fig. 3 is for dual spectrometer use and the use of shutters contained within the fiore optics controls light entering the system. The shutter operation sequence is indicated in Fig. 2.  NOTE while the fibre optic assembly is designed for field use, is delicate and care needs to be take while installing and handling it. There are no user serviceable components in the fibre optic assembly, interfering with the structure of the assembly will void any warranty.  N.B. minimum bend radius of 150mm or greater should be maintained and each fibre should have the same bends to maintain calibration and avoid damage to fibres. Take care not to damage or touch in any way the tips of the fibre optic assemble, this will impede light transmission .

A different fibre optic assembly design has been adopted as standard for Piccolo3  system. The approach adopted in these assemblies is to minimise the differences between instrument line shape function between the up and downwelling channels caused by misalignment of  QEPro spectrometer slit/grating/detector pixel columns emphasised when the length of the slit (1mm)  is used to transmit light. For Piccolo3 fibre assemblies a multicore bundle transmits light to a 600 μm single core fibre which is abutted to the slit. Note this misalignment is only present in some QEPro spectrometer (TeamPiccolo have purchase 12 over recent years and in 3 there is no misalignment evident.

N.B. Please note the crossover block on the Piccolo3 fibre assembly has no ‘user serviceable parts inside’ and attempting to disassemble will irreparably damage the assembly. 

Please also note that the shutters within the fore optics are are very high performance (open or close in less than 5ms if required) and expensive mechanical components (in the order of  £890.00 each with a lead time for replacement of 3 to 4 months).  Any ingress of dust or contamination (such as fingerprints!) on the shutter blade will cause them to fail or operate intermittently.

Figure 4 Schematic of software control architecture

Figure 5 Data format schematic

Details of the software, the Piccolo3 controller and Raspberry Pi3 computer and some guidance on the use of python in this context are in other sections on this Piccolo3 Spectral Systems website and on TeamPiccolo GitHub. All registered academic collaborators (PIs) with Piccolos will have access to GitHub for software and for User Group specific blogs. Note all Piccolo system Pis will have a dedicated GitHub blog to raise queries and request support from TeammPiccolo.

N.B. DO NOT USE THE RASPBERRY PI SUPPLIED WITH THE PICCOLO FOR ANY PURPOSE OTHER THAN PROVIDING A COMPUTER FOR THE PICCOLO CONTROL SYSTEM – ANY INSTALLATION OF SOFTWARE OTHER THAN THAT ADVISED BY TEAM PICCOLO AND AT THE TIME THEY ADVISE, WILL INTERFERE SIGNIFICANTLY WITH THE OPERATION OF THE SYSTEM – THERE ARE PYTHON DEPENDENCIES THAT NEED TO BE MANAGED BY TEAM PICCOLO.

N.B. THE SOFTWARE PROVIDED WITH THE PICCOLO IS OPEN SOURCE AND NO CHARGE IS MADE FOR ITS INCLUSION. USERS ARE FREE TO MODIFY IT TO THERE REQUIREMENTS UNDER ‘OPEN COMMONS’ AGREEMENTS. IT IS THEREFORE NOT COVERED BY ANY WARRANTY. HOWEVER, THE OPERATION OF THE SOFTWARE AND ITS BASIC FUNCTIONALITY WILL BE DEMONSTRATED WHEN THE PICCOLO IS PROVIDED AND TRAINING GIVEN.

N.B.  THE SHUTTERS CONTAINED WITHIN THE PICCOLO2 FORE OPTICS OF THE PICCOLO SYSTEM ARE ELECTRO-MECHANICAL DEVICES AND ARE A CONSUMABLE. THEY ARE MOUNTED WITHIN HOUSINGS DESIGNED FOR FIELD USE. HOWEVER,  THEIR LIFE CYCLE DEPENDS ON USERS NOT TAMPERING WITH THEM OR THE MOUNTING AND ON ENVIRONMENTAL CONDITIONS OF USE. THE SHUTTERS ARE SENSITIVE TO MECHANICAL PRESSURE AND WILL NOT OPERATE CORRECTLY IF OVER TIGHTENED TO SECURE TO THE SHUTTER HOUSING PLATE. THEY ARE FITTED CORRECTLY, AND TESTED, PRIOR TO SUPPLY AND SHOULD NOT BE TAMPERED WITH. THEY WILL ALSO BE SUBJECT TO WARE. UNDER NORMAL USE, SAY 10 OPERATING CYCLES (5 SEQUENCES) 4 TIMES PER HOUR, FOR 12 HOURS PER DAY, THE SHUTTERS SHOULD LAST FOR APPROXIMATELY 6 MONTHS (~ 100,000 CYCLES). PICCOLO3 SHUTTERS ARE OF A HIGHER SPECIFICATION AND SHOULD BE ABLE TO OPERATE FOR 1,000,000 CYCLES OR MORE IF THE FOREGOING OPREATING CONDITIONS ARE MET.

N.B TO AVOID MOISTURE OR WATER INGRESS ALL GLANDS MUST BE FITTED IN ACCORDANCE WITH INSTRUCTIONS GIVEN ON <link to be inserted> NOTE THEY MUST ONLY BE TIGHTENED ONCE.  IF LOOSENED THEY WILL NEED TO BE REPLACED BEFORE REFITTING. IF THEY ARE LOOSENED AND THEN REUSED THEY WILL NO LONGER FORM A MOISTURE TIGHT SEAL. WATER OR MOISTURE INGRESS WILL CAUSE SHUTTERS TO FAIL.

N.B. GREAT CARE SHOULD BE EXERCISED WHEN USING FIBRE OPTIC CABLE AS THESE MAY BE SUBJECTED TO MECHANICAL DAMAGE. THE FIBRE OPTIC CABLES ARE NOT COVERED BY WARRANTY AGAINST MECHANICAL DAMAGE. SEE NOTE ON BEND RADIUS AND HANDLING OF FIBRE OPTIC CABLES ON  THIS WEB PAGE.

OCEAN OPTICS SPECTROMETERS CARRY A 3 YEAR MANUFACTURER’S WARRANTY AND THIS IS ‘PASSED THROUGH’ IF TEAM PICCOLO PROVIDE THE SPECTROMETERS WITH THE PICCOLO. WARRANTY REPAIR IS SUBJECT TO OCEAN OPTICS AGREEMENT.