Opto-Mechanical Designer Needed for Handheld Reflective Color Measurement Device

I am developing a handheld optical measurement device for printed materials and I need support from someone with experience in optical, opto-mechanical, or sensor-based product design. The main challenge is the design of the internal measurement chamber, including the correct positioning of the light source, sensor, optical path, reflection angle, internal walls, aperture, and shielding from external light. The goal is to achieve stable and repeatable reflective measurements on printed paper/cardboard surfaces. The device will include a small spectral/color sensor module, controlled LED illumination, a microcontroller board, battery, display, and a compact 3D-printable enclosure. I already have the electronic components selected, but I need help designing the sensor/light geometry and the internal housing features required for accurate readings. Scope of work: * Recommend the best optical layout for reflective measurement on printed surfaces. * Define the ideal angle and position for the LED illumination and sensor. * Design or guide the design of the internal optical tunnel/chamber. * Help reduce direct light contamination, glare, and external light interference. * Provide practical recommendations for 3D printing the enclosure. * Suggest materials, finishes, diffuser options, light barriers, or internal geometry improvements. * Review or create CAD concepts for the sensor and illumination section. * Help validate the design through prototypes and testing. This is not a generic enclosure project. The most important part is the optical measurement area and achieving repeatable readings. I am looking for someone who understands reflective optical measurement, controlled illumination, sensor placement, and practical product design for prototyping. Experience with spectroscopy, color measurement, optical sensors, LED illumination, camera/sensor housings, or handheld measurement devices would be highly valuable.