Accessible range of motion characterisation of the OpenFlexure microscope

For any hardware to remain accessible, calibration techniques which rely on low-cost and obtainable materials such as easily manufactured test slides are necessary. We present a method of measuring the range of motion of the OpenFlexure Microscope using minimal equipment and a computationally light algorithm suitable for running on embedded software in the microscope. The algorithm uses correlation to measure the displacement between consecutive images. The designed range of motion of the OpenFlexure Microscope is $12.5\mathrm{mm}$ . The method described measured the range of motion as $11.4\pm 0.4\times 11.4\pm 0.5\mathrm{mm}$ . This allows end-users to identify damage to the microscope and scan samples with confidence.