Stylish rock-climbing pants for lower body lighting, increasing safety and visibility in dark environments.

Timeline

8 Weeks The project was organized after each member of the class pitched a final project. After the round of pitches, students formed teams around the projects they were attracted to. Teams Had 8 weeks to build a functioning prtootype of a playful or pragmatic wearable device.

Motivation

The LUMOS team set out to develop a fully functioning pair of durable and desirable climbing pants with integrated lighting for increased visibility and performance while climbing at night. Several key features were critical to accomplish during development to meet the needs of climbers, who rely on lighting at night for safety, and can find themselves in highly dangerous situations without proper illumination. High priority features included the washability of the pants, security of the lights, integrated or invisible circuitry, and optimized light projection. Other important expectations were a long battery life, removable lights, functionality of climbing pants, and overall durability of both lights and pants.

Define

Problem statement: Climbers, whose sport is inherently dangerous and who operate in unpredictable conditions, require reliable lighting solutions that enable them to more easily see hand and footholds at night, with minimal additional gear and without inhibiting their motions or distracting from the act of climbing.

Ideate

The team had multiple ideas going into the ideation phase which would need to be researched before determining their technical feasibility. While we wanted to use LEDs with a very low profile, they often were not bright enough. We investigated the potential to use electroluminescent wire but it was nowhere near bright enough to be beneficial – though the idea of integrating them for their stylish appeal was supported by multiple climbers interviewed. Adafruit sequins were another potential candidate but two issues arose during testing – they were not bright enough, and they also produced an amount of heat great enough to melt trough the synthetic material of a jacket. Through this, we discovered that a light that would be bright enough to satisfy our illumination need would have to have a built-in heat sink, or else risk melting the garment and burning the user during use. The Adafruit Ultra Bright 4 Watt Chainable RGBW NeoPixel LED was ultimately selected as the light source. 

The features of the garment were partially derived from the most desirable elements of other climbing pants that the users were familiar with. These included dual-access thigh pockets to allow users access to contents even while wearing a climbing harness. This meant that the pocket would have to be located on the lower thigh above the knee to prevent the harness from interfering with access. There were several other considerations to account for the position of the user’s climbing harness, including the location and fit of the waist (higher) and length of zipper (longer). To ensure that the lights located at the ankle would not be loose, a cuff would be implemented to secure ends of the pants in place. To make the waist adjustable and potentially unisex, a double cinching integrated built would be built into the back of the pants. Material construction would have to be light, breathable, and durable, and so Palisade Stretch Woven fabric was selected from a set of swatches from an outdoor materials provider.

The lights would take on similar controls to those of a headlamp, a familiar user interaction for most outdoor enthusiasts. The lights would offer multiple brightness options, to allow for sport climbing users to use the pants at a maximum brightness for a shorter period of time, and alpine climbers a lower intensity of light that could potentially extend the battery life throughout the duration of a night. A red light option is common for headlamps to reduce impact on night vision for hikers and backpackers, and would be included as an option for climbers, too. Finally, the “party mode” would add a whimsical element in reference to the counter-culture character of climbers and the debaucherous behavior witnessed at the Twenty-Four Hours of Horseshoe Hell.

Optimized Light Position & Projection

Climbing movement varies drastically between each discipline, style, and climber. To account for this, we would enlist the help of a climber who is skilled at multiple styles of climbing and who has experience coaching climbing at both indoor and outdoor venues. The team wanted to ensure that no matter how, what, or where the wearer was climbing, the pants would provide illumination that would be an improvement over the use of a headlamp alone. This would be done by determining the best location for four high-intensity LED lights on the pants through testing and iterating at a local climbing gym, with the lights off to simulate a similar outdoor environment.

The brightness and beam angle of the light would be another major consideration. The intensity of the lights could be increased by focusing the light into a narrower beam. However, if the objective was to improve visibility for climbers, we had to consider their proximity to the rock wall, wherein the diameter of the spotlight would be reduced the closer they were to the wall and expanded if they moved their legs away from the wall. As climbing walls range from positive slabby slopes to overhung, we would have to use multiple lights in coordination to provide adequate light in a wide variety of situations. The lights would have to project in a wide angle that illuminated as much of the wall as possible at an intensity great enough to be beneficial to the climber.

Integrated Circuitry

Integrated or otherwise invisible circuitry was a priority to ensure that the pants would be appealing to users. With the availability of conductive thread, there was no excuse for any visible traditional wiring to be in the pants, barring unpredicted technical obstacles. This would be done by stitching the pants’ seams with the conductive copper thread, placing the voltage and data line on the exterior of the pants, and the ground inside to prevent risk of a short. The stitching would be done on a standard sewing machine using a stitch which was chosen for its ability to hold the copper thread in place with minimum fatigue - reducing the risk of breaking the thread with extreme movements. 

Removable & Secure Lights

To allow for the pants to be washable, the LED light system needed to be capable of easy removal without introducing a liability that the lights could accidentally eject from their fixture on the pants. A durable case for the lights would be need to be easy to use one-handed, so that the climber could install lights while at a hanging belay station. While removable, the lights would have to be secure enough that they would not be jostled by the rugged movements associated with climbing. 

Prototype

The design of the garment was created from scratch and initially constructed from muslin. After initial fitting and adjustments were made, the final garment would be constructed. 

Multiple iterations were required to develop a light attachment system that would be easy to use, fast, and secure. It was designed using Onshape, a 3D CAD program, and 3D printed using resin SLA (stereolithography) and FDM (fused deposition modeling) printers. Flexible resin materials were used for the LED covers to provide durability and shock absorption to protect both the user and LED from impact with the rock. Rigid PLA thermoplastics were used for portions of the case that supported the LEDs and routed the voltage, ground, and data wires into the lower section, where the contact terminals with the pants would be located.

The flexible LED cover went through two iterations. Initially, it was too thick, and absorbed a majority of the light produced by the LED. To address this, the cover’s profile needed to remain lower than the “bulb” of the LED, with an angled aperture to prevent the case from interfering with the light’s beam width. 

Two versions of the removable light housing were created, using the same principles for completing a circuit from the fixed conductive thread in the pants to the contact terminals on the LED - then back to the pants, where the circuit would continue to the next LED in the series.

The circuitry of the pants would originate at the Adafruit Circuit Playground Express microcontroller, which would be the interface for the user to control the brightness of the lights. Four pins on the controller were used to control the lights on both pants legs in parallel series circuits. 

Test

Testing of each element was completed before their ultimate integration into the pants. Initial testing of the lighting system was done at Boulders, a local climbing gym, using headlamps that were attached at the ankles and knees to get a sense of the needs of the user and to understand the potential for a pants-based lighting system to aid climbers in dark conditions.  

To determine the best brightness settings for the LEDS, we went to a location on campus that allowed a volunteer climber to provide a critical opinion of the pants. First, we took pictures of the lights at increasing 10% intervals so that we could compare the increase in functional brightness, both in person and afterwards, in the side by side comparison above. The climber we interviewed felt that he would most frequently want to use the light at full brightness, but that if the battery life was a concern, he was comfortable climbing at the 30% brightness level for the white LED. We had hoped to be able to borrow an industrial light meter from the industrial engineering program, though after reaching out we could not find one in the engineering department. 

We followed this up with a similar test of the red LED, which seemed far brighter and showed a diminished increase in functional brightness early on. Because the red LEDs use a greater wattage than the whites, we would likely program the red light at the spectrum’s low end. 

In addition to testing the LED brightness, we also refined the locations of the LEDs, now with the intended light brightness settings. Our tester felt that with the light positioned below the knee, it would be better if the light was located at the inside of the knee for multiple reasons: 1) It would prevent the light front being blocked by the rock in most cases. 2) The light would be directed inside a critical zone for finding footholds. 3) The slight concavity between the button of the knee and the top of the calf muscle would largely protect the light casing from touching the rock. 

Lastly, the climber for the majority of testing was solely using the LEDs on the pants to climb. Near the end, the tester mentioned that he wasn’t sure how much he lights would really help compared to a headlamp alone. To challenge this assumption, we turned off the pants and gave the tester a headlamp to test that hypothesis. He quickly retracted his statement, and found that it was surprising how much better the improved lighting from the pants was than his expectations.