For an ongoing photometry experiment I need a complete hardware filter-wheel solution engineered from scratch. The wheel must accommodate 12 optical filters, rotate precisely one position at a time on command, and report its current position back to the host PC. Key requirements • USB(Serial port is ok) is the only accepted interface between the wheel’s controller and the Windows workstation that will drive it. • Position feedback has to be deterministic—optical, magnetic, or any sensing method you consider reliable is fine as long as the PC always knows which filter is in the beam path. • All mechanical, electronic, and firmware design choices are open; choose whatever motors, drivers, MCU/FPGA, bearings, or housings you trust, as long as replacement parts are serviceable locally. • A lightweight Windows utility (CLI or GUI) with a simple API/command set must let me rotate forward/backward one slot and query the current slot number. Shipping source code (C/C++, C#, Python, or similar) is part of the hand-off. • On-site hand-over and initial calibration are required, so you must be based in Bangalore or able to work here in person. Deliverables 1. Mechanical drawings, BOM, and assembled wheel holding twelve 25 mm filters (or advise if another size is more practical). 2. Controller electronics schematics, PCB files, and programmed controller ready for replication. 3. Windows control software with user guide and commented source. 4. Demonstration of repeatable positioning accuracy in my lab. If you have prior experience building motion-control instruments or astronomy lab hardware, I’m keen to see examples. Let’s discuss timelines and any specialised tooling you might need once you review the brief.