My Microscope from France

Hello to all makers!
I’m from France and I have started this project at the bigining of december.
And now I have almost all parts!

I’m always waiting from my leds and resistor to finish this nice project…



Beau travail ! :slight_smile: I’m french speaker from Begium, I’m printing the parts to make one too. May be can you give me some tips to find all material in France and Belgium? Thanks :wink: I’m also active on FB (ATG start)

Je peux t’aider si tu veux :wink:
(I can help U if you want ;))
Justement je suis français mais je travaille en Belgique.
(I am French, but I work in Belgium)

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Super merci beaucoup :wink:

Si tu as une liste de fournisseur en Belgique pour la visserie ou le matos électronique ça m’intéresse :smiley: (ou ce que tu as déjà utilisé, j’ai peur de me tromper de références). J’aimerais faire le high resolution, le but serait de voir des bactéries : )

j’ai mis pas mal d’infos sur les choses qui fonctionnent pour moi(Sourcing non-printed parts)

One of my test with X40 objective and usb controller

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@hiphouser : Nice build. The image on screen is rather green. There should be no colour cast at all after you have done the camera calibration. Sometimes calibration does not work properly, and green is a fairly common failure mode. Try running calibrate again (with the slide removed). That will often work, if not try a third time. If that does not work you will need to delete the current lens shading table and start again. I can’t remember exactly where it is, and my microscope is currently off. It is not an option in the interface, you need to delete the file. When it has worked properly you will have a flat neutral grey background.

Ok, thank for U rely.
I’ll try that for better calibration.
But for now, led missing (in transit from China), and it’s just my room light, not the better way.
About that, is it possible to use the raspberry 3.3v gpio pin for use Led light in place of 5v gpio pin and resistor (to reduce to 3.2v)?
I have in idea to try that way…
Am I wrong?

The resistor does more than just reduce the potential difference across the diode to a particular value. It is mainly there to make the current stable when the properties of the LED change a little. An LED is a diode, once the potential difference is high enough for it to switch on the current increases very rapidly for a slightly higher voltage. Not all LEDs are identical, even in the same part number, and the switch-on voltage varies with temperature. Without a resistor these small variations give huge changes in the current. The real issue is that if the current goes too high you may kill your Pi.

Oh! I’ll use the 5v gpio pin and a resistor! :wink:
What kind of resistor are you use with theses leds:

What the way to calculate that U=R.I but may be other know to have.

It is not really critical unless you want maximum brightness and maximum lifetime. 100 or 60 Ohm are typical. Yours is a relatively low current LED, so needs the higher resistance.

To calculate the best value:
Supply is 5V
The diode forward voltage is 3-3.2V (this is the variability in my last post). Assume 3V here for safety.
The LED maximum current is 20mA.

So when the LED is running there needs to be a potential difference of 5 - 3 = 2V across the resistor. As you say U=I R, so R = 2/0.02 = 100 Ohm

It does not need to be an exact calculation. If the current is lower you get less light, but the Pi camera is very sensitive so that would be OK. LEDs are tolerant of some over current, but not a huge amount, so best to err on the low side. The Pi will easily cope with that current.

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OK. Tank again!