How small a spectrometer can be made?

[I will update this post after testing the sensor]

In a recent post I described a miniature two-channel UV-A sensor with digital interface. Here I will describe a miniature and low cost spectrometer, type AS7265X from ams. It does not used a grating as monochromator, but instead each of the 18 channels has a different interference filter deposited directly on the silicon chip. The FWHM is 20 nm, and the wavelength range from 410 nm to 940 nm. The spectrometer consists in three separate sensor units working together. The interface is digital, and temperature compensation and analogue to digital conversion takes place in the sensor modules. In spite of the number of channels communication between the spectrometer and a micro-processor requires only two wires. The spectrometer supports two different communication protocols, the specialized I2C and a generic serial communication (UART).

Macro-photographs of both sides of an early prototype of a breakout board are shown below. The size of the board is 18 mm × 19 mm. (Photographs were taken as described for the UV-A sensor.)

I bought this board from a seller at Tindie for USD 50. The seller is now selling a differently shaped board, with the three modules in a triangle, and so closer to each other.

Aputure’s Amaran AL-M9 vs. Sunway Foto’s FL-96

Aputure’s Amaran AL-M9 and Sunway Foto’s FL-96 are very small and handy LED light sources. The Amaran AL-M9 has been relegated to a second place in Aputure’s catalogue by the Amaran AL-MX, but I haven’t bought this newer and three times as expensive version. Both light sources compared here are roughly within the same price range.

Continue reading Aputure’s Amaran AL-M9 vs. Sunway Foto’s FL-96

MIDOPT filters

For those interested in photography “beyond the visible”, some of the filters available from Midwest Optical Technologies Inc. under the MIDOPT brand name should be very interesting. They are distributed in European countries by Stemmer AG. Both companies are specialised in the supply of machine vision equipment. What adds additional interest is that filters are supplied in very many different sizes (from M13.25 all the way to M105, mounted and unmounted, and even with mounts suitable for installation at the back of objectives with C-mount).

Continue reading MIDOPT filters