Laser Optics Box

Project Overview

This project was developed for the JHU Physics Demonstration Laboratory for classroom use. The goal was to create a custom optic box that contained five lasers to demonstrate various optics properties, specifically how lenses and mirrors bend light beams.

This project required me to go through the entire development process from designing the housing and custom electronics, to manufacturing and wiring those components respectively. This is by far one of my favorite projects and I am extremely proud with how it turned out!

Design Highlights

Magnetic Capabilities

The bottom of the optics box is a magnetic sheet that allows for the box to be mounted to any magnetic surface (blackboard, whiteboard, etc.)

Toggleable Lasers

The user has the ability to select from having any combonation of the lasers on at once

Adjustable Lasers

Each laser is mounted on a pivot that allows for the beam to be aimed and angled at the user's discretion

Optics Box in Action

The lasers within the box act as individual light rays, enabling easy observation of distinct optical behavior. By passing the beams through a variety of lenses and mirrors (concave, convex, etc.), key properties such as refraction, convergence, and focal points can be observed with high clarity. This helps demonstrate to students how lenses can be used in optics applications.

In the configuration on the left, the optics box is positioned against a blackboard, and all five lasers are directed through a convex lens, clearly illustrating the lens’s focal point as the beams converge.

Design Features

1: Custom Circuitry

Wiring Diagram (Pulsonix)

Soldering the Perfboard

Full Wiring Inside Box

Lasers are mounted in place by top turning knobs

This circuit required the following:

Each of the five lasers shall be controlled by an individual on/off switch
All safety interlocks must be satisfied for system operation (see next section for more detail)

I worked closely with Colman Barth, another employee (electrical engineer) at the Physics Demonstration Lab, to debug any issues with the circuit.

2: Safety Features

Key Switch in Action with Turn On Procedure

Key Switch

In order to turn on the system, the user must engage a key switch. This ensures that the system does not turn on due to accidental button presses.

If the key switch is turned off, the entire system will turn off as well. This bypasses the off button. However, the off button exists for quick turn off as well if the situation calls for it.

Limit Switches

Additionally, to prevent the instructor or user from lifting the box and shining the lasers into the audience, two limit switches were placed with the buttons sticking out of the bottom of the box.

They are wired in series such that if either of them is not closed, the entire system will turn off. The user must press the "On" button again to continue use.

Limit Switch
(One of Two on Bottom)

Limit Switches in Action

The moment the device is lifted, switch is no longer pressed and system shuts off

3: Custom Housing

The metal part of the housing started as an off-the-shelf enclosure box. Modifications to size and mounting holes were made using sheet metal manufacturing machines. The front and back brackets, along with all internal brackets were designed and 3D printed. Use of black was deliberate, as it would absorb the light from the lasers better than other colors.

The full CAD assembly can be seen below, and the execution of the design can be seen to the right of the CAD.

CAD Assembly

Front of Optics Box

Back of Optics Box
(With Labeling)

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