OFM meets a new OSH light source | LIBRE hub

Hi everyone :raising_hand_man:t4: New hands-on workshop from LIBRE hub. This time, participants learned how to build and use a low-cost, modular fiber-coupled laser light source for microscopy. Our documentation is still in progress, but we hope to release it and the English version by January.

As a Technology Fellow, I contributed to this workshop, showing how this new light source could be used with an OpenFlexure Microscope. Participants were interested in building their own OFM.

DISCLAIMER: These are only proofs of concept but are not the most efficient, robust, and safe configurations.

Here are some images from my presentation:

Demonstration with blue laser in a room with artificial and natural light.

Demonstration with violet laser in a dark room

The information on the filters used for these demonstrations can be found here.

The following steps are to design an adapter or use an upright version to mount this new light source and make some tests.

This is a nice imaging modality…

For people with less experience than you I note that the laser powers that you give in your post are very high. Your workshop has a session of laser safety training, which is necessary for those lasers.

Yes, laser safety training was part of this workshop. It was done before building any laser module. We used the minimum current, a short distance between the laser and a black foam board, and a laser safety sign in each station for testing.

Here is a post from a participant where he shared how this step was performed.

To clarify, I was the only one who used an OpenFlexure microscope with this configuration.

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One thing I’ve thought about making for ages but never got round to is some sort of “lid” that would enclose the stage and optics, perhaps bolting on to the bottom of the microscope, or onto the microscope base. This would be a great place to mount that light source, and would also keep the laser inside and the room lights outside. I’m sure you’ve thought of that though - perhaps for the next iteration!

One handy trick I’ve found is that, if you do have a cover like that, you can use a microswitch to interlock it with the laser. It’s very simple, but massively reduces the chances of anyone lasering themselves accidentaly :slight_smile: I’ve previously assumed laser interlocks are horribly complicated and expensive - but in most cases a simple microswitch (or several in series) will do nicely.