Open Colorimeter LED Boards

Each of the Open Colorimeter products ships with an LED mounted and ready to use. We have designed a series of UV, visible and IR LED boards which can be used to customize the Open Colorimeters.

Currently we have 27 wavelengths available in both surface mount and radial form factors:

18 Surface mount LEDs: UV, visible, & IR options. Suitable for absorbance measurements with the Open Colorimeter.

9 Radial (through-hole) LEDs: UV, visible & IR options. Radial LED boards are suitable for use as excitation LEDs with the Open Colorimeter Plus fluorescence measurements. (Note: these can also be used for absorbance measurements with the Open Colorimeter and the UV versions can also be used with the UV Open Colorimeter).

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Open Colorimeter LED Board Design

White LED board (LEFT) and 275nm LED board (RIGHT)

All of the LED boards are designed with these same features in common:

Dimensions: 25.4 mm x 20 mm x 1.6 mm
Two 4-pin JST SH connectors for connecting to the light sensor and PyBadge
Four M2.5 through holes for mounting to the cuvette holder
Surface mount or radial LED mounted in the center

Current Controlled Design

We have added additional components to the LED board design. Earlier versions (Basic LED) without this additional circuitry operated only from a 3.3V input voltage which required modifications to the PyBadge. With the new design, this is no longer required as the on-board voltage regulator enables operation from 3.3V to 5V input voltage.

In addition, the new design includes an active 16mA (or 24mA) constant current LED driver which maintains stable LED current.

Links to the open hardware KiCad design files:

Current controlled LEDs: https://github.com/iorodeo/i_control_led
Basic LED: https://github.com/iorodeo/i2c_led

Customizing the Open Colorimeters

The Open Colorimeter, Open Colorimeter Plus and UV Open Colorimeter can be customized to use these different wavelengths. Instructions for changing LEDs are on the Getting Started Guide page.

Note: The Multichannel Open Colorimeter uses the AS7341 sensor with filters providing the different wavelength channels. The default white LED board shipped with this Colorimeter version is suitable. You can probably still customize further with the visible/IR LEDs to improve specific channel sensitivity though we haven't tested that.

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Open Colorimeter Product Guide

Documentation site for the Open Colorimeter, Multi-Channel Colorimeter, UV Open Colorimeter & Open Colorimeter Plus

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