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Troubleshoot smartphone microscope

Troubleshooting and Improving the Smartphone Microscope​

It may happen that the imaging result doesn't look as good as it could look like. For this we provide a series of explanations to correct for this Overall, with the updated components, the setup should look like something like this:

Perfect Imaging Condition​

Wrong Flashlight Mode​

  • the flashlight has a funky feature to do morse code, this is not helpful, press the button a couple of times to see the brightes light of all different modes
  • The stripes you see is the beating of the pwm controlled intensity and the rolling shutter of the camera

Flashlight too much focussed​

  • The front lens of the flashlight can be focussed - move it to see a more-less homogeneous illuminated sample - this is koehler condition when the led is in focus of the condenser that you move

Flashlight too bright​

  • use a diffuser or older batteries

Distance between Smartphone and Eyepiece too large​

  • ensure the distance between phone and eyepiece matches
  • the Exit pupil of the eyepiece has to match entrance pupil of the phone

Oblique Angle between Flashlight and Sample (kinda darkfield)​

  • when moving the light-source you will see effects such as shadows or reliefs. This is due to the WOTF

Ok Imaging with diffuser between flashlight and sample​

  • incoherent imaging reduces the contrast but gives nice homogeneous illumination

Overexposed but good imaging (koehler illumination)​

Oblique Illuimation (Darkfield)​

  • very opblique illumination, no direct light hits the camera sensor