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  • Writer's pictureSamuel Huang

Pass Me The Lighter

Updated: Jan 15, 2019

Final Paper: PDF Version 

Final Project Blog 


We chose to focus our redesign on the traditional lighter: a portable device that allows users to conveniently ignite a flame and light various objects such as candles, stoves, and cigarettes. In order to use the lighter, a user would need to interact with two different components, the spark wheel and gas valve (Figure 1). Spinning this wheel creates a spark against a flint stone inside the lighter, and pushing down the button opens a value that releases fuel. Since both actions must be executed consecutively, this process can be complicated to perform and understand for inexperienced users. 

After deciding on the object of focus, we created a mind map in order to organize our thoughts and assumptions regarding lighters (Figure 2). We formulated questions and tasks for our interviews based on these assumptions, with the mind map serving as a visual reference for our knowledge.

Data Collection

In order to explore the various problems that may arise with lighters, we diverged and conducted user interviews to establish the scope of our problem space. We employed convenience sampling and interviewed a total of 18 users, with each interview consisting of three segments: screening questions, live demonstration, and follow-up questions. The demographics of our interviewee group was college students with varying degrees of familiarity with lighters, ranging from experienced smokers to complete novices who had never used a lighter prior to being interviewed. Since our mind map illustrated that lighters have a wide range of uses, we wanted our interview pool to accurately reflect that diversity. This will allow us to consider different perspectives and discover more general insights rather than limit our findings to only users who already know how to use a lighter.

The first segment of our interviews was screening questions that were used to learn more about interviewees’ existing biases surrounding lighters. We created these questions in order to better understand the different contexts that people use lighters and whether their preferences influence which lighters they tend to use. These questions included:

- When was the last time you used a lighter? What was it for?

- Do you prefer a particular type of lighter? Why?

- Describe your past experiences using a lighter.

Through our mind map we acknowledged that there were different variations and types of lighters, so we wanted to perform a competitive analysis of the alternatives to traditional lighters in our interviews. This was accomplished through a live demonstration where we asked users to light a birthday candle using three different objects: a long-reach stick lighter, matches, and a traditional lighter (Figure 3). We employed the master-apprentice model and asked interviewees to think aloud and explain their actions step by step as if they were teaching us how to use these objects. By utilizing this model in our interviews, users were able to verbally and visually demonstrate their mental model of how lighters work. Through our observations, we gained insight into the different problems affecting the core functionality of the traditional lighter that arose when attempting to light objects such as the birthday candle. Furthermore, detecting user errors in conjunction with discovering why the stick lighter and matches have certain desirable features over the traditional lighter will aid us in an error-driven redesign that takes inspiration from market competitors.

Lastly, we asked users follow-up questions after completing the demonstration portion of the interview to learn more about users’ preferences and what qualities they value in a lighter. These questions included:

- Which one would you use in the following situations and why?

- Indoors

- Candles/birthday candles

- Stove

- Outdoors

- Campfire/BBQ

- Smoking

- What features do you think a lighter should have? What is most important to you (rank it)?

These questions were asked after the demonstration segment in order to provide infrequent and new users with a recent experience to reference (as some users last used a lighter several months ago and could not recall their experiences in detail). Although these follow-up questions might be biased by the preceding demonstration, we attempted to account for this effect through the screening questions in order to determine what kind of initial preferences each individual had before the demonstration.

After finishing our interviews, the raw data was anonymized and organized into a spreadsheet. This helps to protect the confidentiality of our participants while allowing us to honestly and accurately present our findings.

From our interview data, we identified common trends and converged onto core problems that 50% of users encountered while using the traditional lighter (Figure 4). Across these users, there were two main problems which caused difficulties that affect the functionality of the lighter; these problems prevented users from reliably igniting a flame.

About 22% of the users had the correct mental model of the lighter, in that they understood that both the spark wheel and the gas button had to be used in order to successfully create a flame. However, despite their understanding of how to properly use it, they were physically incapable of activating it (Figure 5). The action of consecutively spinning the spark wheel and clicking the button was difficult to execute because of the velocity and the pressure required. Though despite the physical demands to use the lighter, we acknowledge that this design was implemented for safety reasons. The physical constraints that these two components impose create an anti-affordance which protects against accidental usage (during storage) and prevents misuse from unintended users (i.e. children). However, as our data suggests, this design that was meant to provide safety actually interfered with intended usage instead. It prohibits quick, actionable usage and prevents the ignition of a flame, hindering its functionality.

In addition, 28% of users had the incorrect mental model and only interacted with one of the two components necessary to spark the flame (Figure 6). This primarily occurred with first time users who have never used a traditional lighter prior to the interview. We classified this error as a knowledge-based mistake because users lacked knowledge about the mechanisms and steps needed to start the lighter. The users would either only spin the spark wheel or only click the button but did not understand that both were necessary for the lighter to ignite. The design itself lacks signifiers that state that the spark wheel must be spun and the button quickly pressed right after. This is unintuitive to many first time users who found it difficult to bridge the Gulf of Execution as the design fails to provide instruction and implications on how to activate the lighter.

Another noteworthy finding was that of the half of participants who encountered difficulties using this lighter, 22% of them expressed fear regarding usage. One individual stated, “I’m scared that I will burn myself” and was excused from performing the demonstration. Although this provided a minor gap in our data collection for this particular interview, it was important to respect our participants’ limits and value their comfort. However, we did gain valuable insight from those participants who expressed fear: there is an emotional aspect of perceived safety in using a lighter. Even though this was not a problem that directly affected the functionality of the lighter, it affects the practicality of it. What good is it to be able to ignite a flame if the user doesn’t feel safe using it to light anything?

Our findings allowed us to explore a variety of different problems that users faced when using traditional lighters. After analyzing for common trends, we converged upon these core problems and defined a problem statement: “How might we design a lighter that is easy to use and understand, feels safe, and preserves the essential qualities of a lighter such as portability and protection against accidental usage?”

For our first design space, we plotted the traditional lighter and different alternatives along the axes of ease of use and safety (Figure 7). We decided to focus on ease of use and safety first because 61% of users described both of these as one of their desired qualities in a lighter. In addition, our data revealed that half of the interviewees struggled with using traditional lighters and 28% expressed the desire for the flame to be further away from their fingers, with 11% feeling that the flame was going to burn them. Because of this, we are defining safety as the distance between the user’s fingers and the flame. Ease of use is defined as the relative intuitivity of the lighter and the difficulty of using the mechanisms involved in igniting the flame.

We plotted other types of lighters in the design space to see where each one lies and what tradeoffs were made. From the demonstration segment of our interviews, we found that a majority of users had difficulty igniting the long-reach stick lighter due to the two mechanisms that need to be used (the trigger button and safety lock). Similar to how the traditional lighter has two components (spark wheel and gas button), those physical constraints are put in place to ensure that the lighter cannot be accidentally lit or misused by children. These safety constraints also contribute to the difficulty of using the stick and traditional lighters, so they are similarly rated low on ease of use. However, we considered the stick lighter to be safer than the traditional lighter because it had a long nozzle which increased the distance between the flame and the user’s hands.

On the opposite end of the spectrum, we classified electric lighters to be more safe and easy to use than the traditional lighter and other alternatives. This is because electric lighters only require users to press a button in order to activate which makes it incredibly easy to use. Additionally, the button used to activate the flame is positioned on the side of the lighter which keeps the user’s fingers away from the flame and provides an increased sense of safety. However, a tradeoff is that while a one-step button is easy to use, it does not guard against any accidental usage like the stick or traditional lighters with their two-step activation mechanisms.

Based on these axes, the ideal lighter design would fall towards being easy to use and providing a safe distance from the flame, with a consideration for the possible dangers of unintended usage and protecting against it. Our redesign would ideally utilize the best features of each lighter, such as the length and safety lock of a stick lighter and the easy activation of an electric lighter that places the user’s hand a comfortable distance away from the flame. However, one necessary tradeoff is that while our redesign is easier to use than the original traditional lighter, it sacrifices some ease of use to provide more protection against accidental usage than an electric lighter. This is because we want to preserve that feature from traditional lighters and design something that accounts for human error.

For our second design space (Figure 8), we compared portability and versatility because our interview data revealed that these factors determined when a traditional lighter was or was not preferred in certain situations. Across a variety of situations, only 11% of users described the traditional lighter as their preference due to its portability because it is small and compact. However, the tradeoff for portability is that it limits its versatility regarding which situations an individual could practically use it in. Its compact design results in a flame within close proximity to the users’ hand. This makes small, accessible objects such as cigarettes easy to light but restricts its versatility in lighting hard-to-reach objects such as candles in a confined jar and dangerous gas stoves. This is why we place the traditional lighter as relatively portable but less versatile than alternative competitors.

The alternatives that rated highly on versatility are objects such as matches and long-reach stick lighters because of their relative wide variety of uses. Matches are disposable and can be thrown into large, dangerous fires such as BBQ grills and fireplaces while stick lighters provide a safe distance from gas stoves and candles. Both of these can practically be used in situations that the traditional lighter struggles with. However, potential a tradeoff for versatility is that the elongated design of the stick lighter makes it less portable than compact designs such as the traditional lighter. Matches are both portable and versatile, but the tradeoff of its disposable design is safety (Figure 7) with the flame extremely close to the users’ fingers and quickly moving closer as the match burns.

On the other side of the spectrum, Zippo and electric lighters are still portable due to their compact size but not very versatile (Figure 8). This is because while these types of lighters were relatively safe (Figure 7) since the user’s hands hold the lighters from the sides away from the flame, their design hinders the number of practical uses available. The protective cap of the Zippo lighter restricts the ways in which you can grip the lighter and hinders movability in confined spaces, causing it to suffer from similar problems as the traditional lighter. The electric lighter is the least versatile because it begins as a beam of electricity instead of a flame which seems impractical for lighting campfires or gas stoves.

As illustrated, the axes of these design spaces are intertwined and objects need to be examined in a multi-dimensional space with various qualities and tradeoffs between ease of use, safety, versatility, and portability. Figure 8 suggests that the ideal design should preserve the portability of the traditional lighters while providing versatility in how individuals use it. However, we also need to consider the insight gained from Figure 7 that plots the design space for ease of use and safety. Our redesign needs to be safe and easy to use while guarding against unintended usage. And so, we once again approach our problem statement with new insight on where in the design space we want our redesign to reside: “How might we design a lighter that is easy to use and understand, feels safe, and preserves the essential qualities of a lighter such as portability and protection against accidental usage?”

Throughout our redesign process, we utilized the  Double-Diamond model of design to diverge into various usability issues and converge onto core problems and trends in order to define a problem statement. Now we need to once again diverge and brainstorm possible solutions. We first began by ideating various solutions (Figure 9) based on our problem statement and design space. These ideas included motion-activation, a fingerprint scanner, and an extended nozzle that functioned like a lightsaber (Figure 10). Although these ideas seemed crazy and impractical, being creative without constraint allowed us to gain insight that eventually led us to our redesign ideas. For example, the idea of a lightsaber is a one-step activation that resulted in instantaneous feedback, with the laser shooting out of the base with a click of a button. From this concept, we converged on the idea of incorporating a nozzle on the lighter that extends in a similar fashion that the laser in a lightsaber extends (Figure 10). This compressible nozzle that only extends when the lighter is activated addresses the issues of safety and portability, as it provides a safe distance from the flame for users while maintaining a compact design.

We again diverged to explore the different mechanisms that could be involved in this extended nozzle idea. In our first prototype (bottom of Figure 9), we converged on implementing a slider that would be used as the main mechanism to unlock the lighter and extend the nozzle, with a button that would be used to ignite the flame. The nozzle extending as the slider is being raised would function as a feedback mechanism which would notify users that they took the correct action, helping them bridge the Gulf of Evaluation. In addition, the activation method would be a simple button on top of the lighter. This addresses the ease of use of the lighter because the button provides physical constraints in regard to the number of actions the user can perform. It signifies to the user that it only affords to be pressed down due to its slight protrusion. Our reasoning for this initial prototype was that this fluid motion (pushing the slider up the length of the light and then pressing down the button at the top) would be more intuitive than spinning the spark wheel and consecutively pressing down the gas button.

We continued to iterate upon our initial prototype to think through the mechanics of the lighter and further improve our design (Figure 11). Again, with our problem statement in mind, we wanted to protect against accidental usage that could be caused by human error, such as users forgetting to push the slider back down to lock it or keeping it up at all times in order to quickly ignite the flame. We addressed this by having the slider automatically retract down after the user releases the activation button to prevent any misuse. Another key iteration of our original prototype (Figure 10) is that the activation button at the top would only appear as the slider is pushed to the top (Figure 11, left). This would make the lighter more intuitive to use since it implements a forcing function where the user’s actions are constrained. Having the activation button visible only when the slider is raised serves as an interlock that forces the operations of this lighter to occur in the correct sequence and guides the user.

While this design addressed ease of use, safety, and portability while guarding against accidental usage, we still wanted our redesign to be versatile in different situations. So, we diverged to explore different slider options and the potential of a two-way flame such that the user had the option between a close-range flame that the traditional lighter currently provides and a long range flame that the stick lighter provides (Figure 11, middle and right). The reasoning behind this is that while our data demonstrated that the length of the stick lighter makes it preferable in a majority of situations, 83% of users still preferred the traditional lighter in situations such as smoking. We wanted to account for both situations and this led us to converge onto our final redesign which includes a single slider and a two-way flame (Figure 12).

For our final redesign, we kept many of the initial concepts from the previous iterations. In order to use our redesign, users would still need to first push the button inwards in order to slide it upwards. This was designed to protect against accidental usage and deter unintended users (such as children) from being able to easily ignite the flame. This action is signified to the user by the protrusion of the button and further guided by the physical constraints of the slider; the intrusion of the slider path signifies that the slider only affords an upwards or downwards motion. By having a restricted path of motion, users have an ease of use and intuitively know what to do.

Once the slider reaches the top, users would switch the button to either side depending on where they want to ignite the flame (Figure 12). If they want the flame to ignite on top, there would be a signifier (an icon) telling them to slide the button the right and if they want the fire to ignite through the long-range nozzle from the front, there would be another signifier telling them to slide button to the left. The extended nozzle provides safety through an increased distance from the flame while the option of igniting the flame at the top helps improve the versatility of the lighter. By having two possible locations for flame, individuals are able to use the lighter in more situations while maintaining portability since the design remains compact as the nozzle can compress.

Although our redesign significantly improves upon the traditional lighter and encompasses the better aspects of our design space while addressing our problem space, there are still two tradeoffs made. While our redesign is easier to use and understand, first-time users may not find it as initially intuitive as traditional methods because of cultural constraints that influence their pre-existing schemas. For example, one participant had never used matches before but experienced no difficulties lighting one because he knew that he “has to swipe the match-head against the rough part” based on what he saw on television. In addition, the sliding activation mechanism of our redesign challenges the mental models of users who have experience with the spark wheel mechanism of traditional lighters. Therefore, intuition reinforced by cultural constraints and past experiences is a tradeoff made in favor of ease of use.

Furthermore, a consequence of the ease of use behind our redesign is that it is easier to unlock than the traditional lighter, making the lighter easier for children or users to accidentally activate it which could endanger them. This is another tradeoff that we chose to make because while unintended usage is important to consider, our data demonstrates that ease of use was users’ most prioritized quality (61%). However, we still wanted to minimize accidental usage and so our redesign still has a safety lock and automatic retraction of the slider.


In conclusion, utilizing the Double-Diamond method allowed us to diverge to explore different user problems, converge onto core problems that helped define our problem statement, diverge once again into possible solutions, and converge onto a final redesign. Through iteration, we were able to refine our initial prototypes and ideate different solutions that addressed the core problems that affected both the functionality and practicality of traditional lighters. Our final redesigned lighter is data-driven and incorporates solutions to the problems we had seen during user testing. We made decisions to make certain tradeoffs in order to maximize ease of use, safety, portability, and versatility. Future steps for this project would be developing a physical prototype to conduct more user testing and observe user interactions. These observations would give insight into the assumptions that we may have made regarding the intuitivity of our design by illustrating where users are prone to errors. After doing so, this feedback will be valuable to drive iterations and further improve upon our lighter redesign.

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