RGBA board for absorbance/fluorescence?

[noahsprent]

I continue my adventures with different absorbances/fluorescences with the Pioreactor. The Labcrafter folks (@gendor) very helpfully provided me with an Adafruit TSL2591 and one of the LED boards that iorodeo designed for the open colorimeter.

The sensor seems to work fine, but I’m realised that with a spectrometer like Adafruit AS7341 I can get 10 channels for about £15 and there is already a plugin GitHub - Pioreactor/spectrometer-reading-plugin: Take a spectrometer reading using the Adafruit AS7341 spectrometer sensor every 5 seconds between OD readings. · GitHub .

Additionally, in the end I’m not sure that the LED board from iorodeo is the right fit for the pioreactor because (as far as I understand, I’m not an electronic engineer!) it is designed to resist changes to current whereas the pioreactor relies on changing current via PWM to brighten/dim LEDs. So turning it on/off proves to be a little tricky.

I’m working with the pioreactor XR which doesn’t have any additional slots for LEDs, it only has space for boards.

So I wonder if anyone has found, or has made, an LED board like the one from iorodeo but that is designed to play nicely with the pioreactor? It seems to be that i2c from the HAT can supply up to 1amp so should be fine on the power front to control and power the LED from that. It looks like there are very cheap/standardised chips (Access to this page has been denied.) and RGB LEDs (https://www.digikey.co.uk/en/products/detail/qt-brightek-qtb/QBLP1515B-RGBA/5957597) that could put three on one board, or arbitrary LED colours would also be fine.

A combination of an RGB board + the adafruit spec would be pretty nice for fluorescence work assuming long stokes shift species were used.

[gendor]

Hi Noah!

A while ago I wrote an experiment profile for the AS7341 spectrometer board to turn the white light LED on that board on and off if that helps:

Normally on spectrometer led

I just wrote an experiment profile to keep it on for 20 hours and then turn off for 4 hours: experiment_profile_name: Spectrometer Daily Cycle metadata: author: Gerrit Niezen description: Cycles the spectrometer on for 20 hours and off for 4 hours to use the light for microalgae growth. common: jobs: spectrometer_reading: actions: - type: start hours_elapsed: 0.0 - type: stop hours_elapsed: 20.0 - type: repeat hours_elapse…

Yes, unfortunately the the IO Rodeo LED boards can’t be controlled automatically. I think IO Rodeo has been working on a version that can be controlled via I2C - I’ll get in touch with them and get back to you.

It would be interesting to see if an RGB board would work for fluorescence, as you usually need very specific wavelengths and/or filters and I’m not sure if they’re bright enough?

[noahsprent]

Please do let me know about IO rodeo!

In general my approach with this would be to use fluorophores whose excitation matches the light source rather than the other way around. Then if you use ones with long stokes shift the emission is at a very different wavelength to the excitation and so you shouldn’t need filters. E.g. excite using blue LED and then read the red channel on the spec.