Proton Pack + Neutrino Wand

From sketches to sheet metal and military-grade weapon parts, a look at the redesign process of the Ghostbusters’ proton pack and neutrino wand

Gowtham, with the final product.

To think outside the box, sometimes you might have to put yourself in an imaginary world. That’s what my teammates Alicia Geller, Gowtham Ashok and I did when we decided to build a modernized proton pack and neutrino wand for the Ghostbusters.

I learned and built on so many skills while working on this semester-long project, including:

  • Hardware (soldering, using a circular saw, building a simple circuit)
  • Iterative product design
  • Usability testing and user analysis
  • Quantitative and qualitative evaluation
  • Silent observation

Here’s a look at our redesign process, a project for our Introduction to Human-Computer Interaction class (INST 631, taught by Dr. Jen Golbeck):

The proton pack and neutrino wand are essential to the Ghostbusters’ success. Without it, the team members wouldn’t be able to trap the ghosts that terrorize people in their homes and offices. While the existing device is effective, the design leaves room for improvement. With our redesign of the proton pack and neutrino wand, we aimed to improve the device’s usability and efficiency.

Project Description


The Ghostbusters must be prepared to head out on ghost-trapping missions at any given moment. Their success heavily relies on the quality of their equipment, so we aimed to focus on creating a device that was lightweight, durable, flexible and user friendly.

Keeping these points in mind, we also wanted to make sure the new prototype felt familiar to Ghostbusters who have used the original pack but improved their interactions with the device.

User Analysis


Through interviews with our early user testers, we determined the most important feature to focus on was creating a lightweight device that enabled users to find a ghost and shoot it without getting fatigued.

Device Features

Neutrino Wand

  • Instead of continuing with the handheld grip design, we opted to create a forearm attachment with a finger grip that connects to a trigger
  • Added a riflescope, live-view display and laser sight — all removable
  • Sturdy, adjustable cloth base allowing for flexibility to give users complete control over their actions
Proton Pack 

  • Eliminated gimmicky look of the original pack
  • Simplified the interface, enclosing elements such as wires and ribbons in the polished metal exterior

Design Process

Several rounds of user testing helped refine our prototype, which started as a paper-and-pen sketch. 

Proton pack and neutrino wand sketch

Round 1

After developing a low-fidelity prototype, we recruited three participants for usability testing. Two of the users had previously shot several types of guns. The third user had never before picked up a gun. The prototype — made of a backpack, cardboard, styrofoam and plastic bags held together with packing tape — allowed test subjects to focus on the interface and not the aesthetics.

What we did

  • Analyzed users’ actions to see if they would see the correct controls, understand the functionality of the controls and identify system feedback.
  • Asked users to put on the pack and wand, climb a flight of stairs and aim at a picture of a ghost-like target.
  • Asked each user to use one of three methods: silent observer, talk-aloud and constructive interaction.


  • In a rush or without guidance, some users put on the neutrino wand incorrectly.
  • Two users were unsure how to aim at and shoot the target. One user noticed a “target acquired” message on the screen, but he said he did not know if that meant the ghost had been trapped or just spotted.
  • Tasks were minimally affected by memory load. None of the users had difficulty recalling the proper order of completing tasks, and all eventually managed to spot the target and trap the ghost.
  • All users said they felt comfortable with the prototype’s size, but all three requested that the next iteration of the prototype more closely emulate a gun. They found that a cardboard forearm base and grip inhibited mobility of both the wrist and elbow joints.

Round 2

We revised the wand’s grip and added buttons and switches to the interface. The resulting equipment strongly resembled a gun. While our test users preferred this design, we determined we needed to make the final design look less gun-like for safety reasons.

Alicia, testing out our revised prototype. We told our professor we worried it might look too much like a real gun, and sure enough, she told us we had to change it — despite our test users’ wishes for a traditional hand grip.

We tested six users — five men and one woman — between the ages of 20 and 23. 

Pretest Questionnaire Findings

  • Five of the six users had experience with using guns, and the same five have played video games that involve shooting.
  • None of the test users had ever served in the military, an important consideration because the wand utilizes military weapon parts.
  • All rated their hand-eye coordination as a 3 or 4 on a scale of 1 to 5, with 5 being perfect hand-eye coordination.
  • Four of the six users had seen Ghostbusters at least once, and all users were at least somewhat familiar with the concept of using a proton pack to target ghosts.

Usability Test Observations

  • No user struggled to pick up the proton pack, but four users carried it with one arm, leading us to determine that the pack’s weight was too unrealistic.
  • The hose stayed firmly in the proton pack but slipped out the end of the neutrino wand during two tests. One user got tangled up in the hose but recovered without assistance.
  • Some users used the riflescope; others used the live view display. Some tried both tools, and one used neither feature.
  • The participants all found the target without hesitation, but they all struggled to find the trigger located on the left side of the wand above the hand grip.
One of our test users, on the lookout for “ghosts” that might be lurking in his house.

Post-Test Discussion 

Post-test interviews and questionnaires with the six users led us to make the following adjustments or add these features in the final prototype:

  • Location of trigger: placed more prominently upon the hand grip
  • Switch and light bulb shows when proton pack is on
  • Working laser light
  • Ghostbusters branding on proton pack
  • Sheet metal and wooden frame to solidify the proton pack’s exterior
  • Flexible forearm base and detachable hand grip to replace gun-like hand grip
Ghostbuster testing
One of our classmates during the in-class testing day. We even had real Ghostbusters outfits so our users could look the part!

Quantitative Evaluation

We conducted usability tests on the final prototype with seven new users. The tests focused on speed and efficiency, learnability and memorability. The test consisted of the same steps described in the second round of usability tests.

Recommendations and Observations 

  • Users have varying preferences for how they interact with the trigger. Some prefer that the button rests on top of the hand grip, while others want it to be more on the side.
  • The laser (which we did not allow users to use for safety reasons) would have helped provide visual feedback for when users pressed the trigger.
Ghostbusters proton pack and neutrino wand project presentation.
Final project presentation — QVC style!

Further Applications

Ghostbusters might be fictional, but the proton pack and neutrino wand design could serve legitimate real-world purposes. We imagined the design concepts could be applicable in creating weapons for specialized military units and SWAT teams, or even space tools for astronauts. No matter the group goal, critical needs such as comfort, mobility, modularity, adjustability and sturdiness would hold consistent. Any of these users would need to be able to carry the equipment for an undetermined length of time and hold it with relative ease.

The neutrino wand’s design involves modularity and can easily be broken down into smaller parts for storage. It utilizes two visual acuity methods: a riflescope and a live view display. Both function similarly and serve as a backup in case the other option fails — perhaps the phone’s battery dies or the riflescope goes out of focus. They also help users to stay on target no matter the brightness of the environment.

In a military-like case or police situation, safety is vital, and the design of both the wand and the pack considers this need. The live view display provides a way to view an environment from a safe distance. The pack can serve as energy storage for a taser wand (instead of neutrino wand) used to subdue criminals. The pack would also provide extra energy and power, allowing users to stay in the field for longer durations of time.

The design could serve other types of users as well, especially if the wand concept is seen solely as a tool and not a weapon. Astronauts could use a revamped wand as a portable power tool strapped to their forearm as they’re fixing the International Space Station, a telescope or other spacecraft. The tool would be powered by the attached proton pack, which provides power, and controlled by the trigger-like button affixed to the hand grip. The joystick moves in all directions and could help prevent injuries caused by repetitive motions.

Currently, space tools like hand drills have a pistol-like grip and a large screen that displays information. It’s designed with an astronaut’s gloves in mind. The tool is also modular so engineers can add modifications later on. Engineers aren’t too quick to change the design since it’s worked pretty well since 1997, but the tools aren’t without their faults. Astronauts face severely limited mobility and often suffer from hand fatigue. Even with special grips and handles, using the tools can get exhausting quickly. Freeing astronauts from having to tightly grip a gun-like grip — and instead strap the tool on their forearm — could have enormous impacts on the lengthy spacewalks. As NASA begins its early preparations for sending humans to Mars or Russia starts prepping for a moon base, this could be a prime time to rethink the design of existing space tools.

The parts of the proton pack could also be separated and reworked for biomedical purposes. A February 2015 article by IEEE’s Evan Ackerman discusses how the Defense Advanced Research Projects Agency and Open Source Robotics Foundation have developed prosthetic limbs that simulate an actual working limb. It works via a brain-wired interface, similar to an innovative design created at Johns Hopkins University’s Applied Physics Lab, which they announced in 2013. Our design could use the concept of energy storage by minimizing the size of the storage pack and using a smaller hose similar to the existing DARPA and OSRF design shown here. In this case, our aim wouldn’t be to reinvent the wheel so much as it would be to integrate our pack and wand concept with existing bionic designs. Many firms are working in conjunction with federal government agencies to find ingenious methods to alleviate the trauma of losing limbs in battle. The research and development findings would also assist the general civilian population, in cases where individuals have lost limbs due to illness, injuries or genetic makeup.

In all three cases, slightly reworked versions of the existing proton pack and neutrino wand show that the design is transferable across fields. Certain environmental factors — maybe the frigid temperatures of space or a hot desert climate — would affect specific design aspects, but the general shape of the equipment could still be used.

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