Hello. I have little experience with these things so I am seeking help here. I have a prototype design for a liquid drop monitor. There is a tube that drip liquid and be detected by a photodiode hooked up to an Arduino. My question is about how to build an enclosure for it subject to my requirements. If anyone has advice for any of my needs below, the help would be much appreciated. I am not very knowledgeable of these kind of things. The circuit is in in two parts on two small breadboards, the detector on one side and an LED on the other. A tube will go through the box vertically from top to bottom. The box will be made out of acrylic because it's cheap, see-through, and I have access to a laser cutter. First question, how can I mount these breadboards in the acrylic box in such a way that I can remove them when needed or later replace them with a PCB later. Second, what sort of mechanical device can I use to adjust the distance between the LED and the detector? Essentially, I just need to be able to move the LED towards and away from the detector in one dimension. Third, I will need to change out the tube often to adjust the thickness. How could I allow for adjustable sizes? If the tube hole is the same size then I will only be able to fit one. Alternately, I could move the detector and LED horizontally to select different tubes. Is there a mechanical device for this? Fourth, I'm using acrylic because it's cheap and I have access to a laser cutter, but most designs for boxes I've seen are not made to be opened. I will need to be removing and rewiring things often. So is there a common or easy way of making/mounting a hinged acrylic door or a removable top? I apologize for the simplicity of my questions, but I really could use the help. Thanks!