Soil Sampling Update: Spore Stepper

Since conceptualizing the shoe that takes in soil samples, I have taken steps to implement this idea into an object.

Precedent Works

In looking at precedent works, there are a wide range of projects that have embedded technology into footwear. A common thread throughout these projects is that the functionality of the shoe depends on the movement of the wearer in order to actuate it.


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The Nanohana Heels is a project by artist Sputniko! in collaboration with shoewear designer, Masaya Kushino. This pair of shoes was developed in 2012 following the Fukushima Daiichi nuclear disaster in Japan during Spring of 2011. As demoed in a video about the shoe, with each step into the earth, rapeseeds (nanohana in Japanese) are dispensed from the stiletto point of the heel. According to Sputniko’s website, Belarusian scientists have determined that rapeseed blossoms are able to absorb radioactive substances. This research was done on lands affected by Chernobyl in the 2000’s to consider remediation of lands. By planting rapeseeds with each step, the shoes seek to question how to heal the land damaged by the nuclear disaster through action.

For the soil sampling shoe, an opposite effect is desired, in which matter is collected rather than dispensed.  Also instead of each step leading to soil collection, the action will have to be spaced out through out the duration of the walk, otherwise a lot of soil would be collected. Based on prior research on soil sampling, 40 mL of soil is suggested for a sample. This sample would then need to be located near the foot, whether directly in the shoe, or perhaps near the foot around the ankle.


E-Traces by designer Lesia Trubat documents the movement of dancers through sensors placed on the ballet shoe. This movement is then sent via wi-fi to a smart phone which then presents the traces performed by the dancer. This project seeks to create a digital artifact of the performance to function as a visual image to allow the dancer to study their movements in order to learn and improve from this tracking.

In considering the tracking function of E-Trace, this could provide an understanding for development of a tracking function for the soil sampling shoe. This would allow the shoe to determine when to collect soil, based on where on it’s position of a space, such as a park or trail.



Roller shoes are a type of footwear with an embedded wheel, allowing the wearer to glide across a surface when the weight is shifted onto the heel. Roger Adams, the founder of roller shoe company Heelys, patented this design in 1999 and has geared it towards the youth market ever since. Based on the company website, he “cut open a pair of sneakers, inserted a skateboard wheel, and Heelys were born!”. Current Heelys sneakers also feature a removable wheel which would allow the wearer to step without rolling. Although Heelys and other roller shoes are popular due to its recreational aspects by embedding a normal shoe with the potential for rollersport activity on any flat, hard surface, this has come not without controversy.  From frustrated pedestrians and shopkeepers to concerned pediatricians, roller shoes is seen as a dangerously annoying and annoyingly dangerous footwear. However, even almost 17 years since this product come onto the market, several retailers still carry roller shoes in their inventory.

As a precedent work for the soil sampling shoe, roller shoes serve to be an interesting design for how technologies are embedded into the shoe, particular in the heel which makes direct contact to the ground.  The pressure on the heel activates the wheel in the roller shoe, allowing the wearer to glide or roll across their surface. This insight provides consideration into how the wearer must interact with the soil sample shoe in order to facilitate the collection process. Although the shoe provides a more passive soil collection compared to existing methods, certain actions or gestures must still be performed in considering the interaction design aspects of the object. The soil extracted from the ground for the soil samples collected by the shoe needs to be accessible for analysis, thus can follow the retractibility of the wheel in the roller shoe.

First Iteration

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In the first iteration of the soil sample shoe (working title is “Spore Stepper”), a circuit was built onto an existing shoe to allow soil sampling to occur. A circuit that controlled a servo motor was built that was controlled by a pressure sensor switch. A scoop and collection bag are built on top of the servo motor so that when the pressure sensing switch is closed, the servo motor would pick up dirt using the scoop attachment and deposit the dirt into the bag located directly behind the scoop. This circuit was then fastened to the a Vans Classic Slip on shoe by using zip ties to connect the breadboard where the microcontroller and some of the components are held to the flat part on top of the foot. The design of this shoe allowed for easy access to fasten the breadboard onto the surface. The switch was installed inside the shoe where the ball of the wearer’s foot would reside.  This would allow the switch to be activated when pressure was placed at the front of the shoe, such as when the user is mid-step. The servo motor is then placed on the inner side of the shoe, adhered to the shoe using hot glue. The scoop attachment is angled downwards, so that soil would automatically get pushed into the scoop when the scoop is made. As the wearer steps, the servo motor is triggered, which dumps the dirt collected onto the scoop into a collection bag located at the other end.


This low-fidelity prototype is an early proof of concept to show a possibility of how a soil collecting device can be attached to a shoe. Although it is functional, several design and technical considerations can be made to refine this prototype. One major design consideration is how to fully integrate the components into the shoe rather than having the components sit on top of the shoe. This would entail building the electronics into the shoe in a more seamless manner. A technical consideration is to use another method of soil collection that would allow the soil to be collected more naturally with the step action of a user, rather than having a servo motor pick up the dirt.  An addition of an inflation bulb such as the ones used for a turkey baster or blood pressure pump would allow for suction without digital components, though placing of this component in the shoe for proper inflation and deflation would be complicated without constant collection happening by the suction. Initial tests with a turkey baster also did not prove to be successful in collecting dirt.

One method to reconsider the soil collection methods is to use soft robotics to move the soil into a collection chamber inside the shoe. The soft robotics would take form of a pneumatic muscle located in the outsole of the shoe that can expand and contract to push the soil into a collection chamber also located in the outsole. The natural pressure from taking a step would push dirt into the entrance of the muscle through the tread. Only when the shoe is ready to collect dirt, through tracking the distance in between the last time of collection or at discretion of the wearer, the muscle will activate to “swallow” dirt into collection.

Although it would still need digital components such as a pump, microcontroller and power source, a soft actuator would be easier to implement into shoe rather than accounting for the full range of motion that is required by the servo motor. At this point in building the prototype, the actual artifact of the shoe was taken into consideration. As a speculative piece, it was important for the object of the shoe to present the potential functionality and conceptual elements of the piece, more so than to be a robust, efficient model (at least this is what I am telling myself).

To test out this method, I followed instructions set forth by the Soft Robotics Toolkit, an open resource for building soft robotics created by Harvard University and Trinity College Dublin, for building a fiber-reinforced actuator using a cardboard mold. A two part mold was constructed using cardboard pieces and then reinforced by hot glue to prevent leakage.  EcoFlex, a silicon casting material by SmoothFlex, was then prepared according to specifications and poured into the mold. A piece of paper was placed in between the silicon on the top layer to act as a stiffener. This would constrain the actuator to bend in a specific manner rather when it is inflated.

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After curing, the silicon pieces were pulled out and adhered to each other with additional silicon.  Tubing was then inserted inside the actuator to the open chamber, which is then attached to an empty plastic bottle. The empty plastic bottle acted as a impromptu pump to inflate and deflate the silicon actuator.

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By designing this silicon piece in a cylindrical shape with sections to inflate in succession, the actuator would be able to push dirt through a tube. This action would mimic swallowing, with the dirt being deposited in a “stomach”, or a storage area to be held until the walk is over and the collected dirt can be obtained for analysis. In considering how the cylindrical actuator will be designed, the work of F.J. Chen et al. for their work, “Soft Actuator Mimicking Human Esophageal Peristalsis for a Swallowing Robot” was referenced. This research developed a soft actuator that replicated a human esophagus to swallow by building a silicon body with horizontal chambers that would inflate in succession to mimic the muscles utilized in a human model. Although this design yields a model that is larger and more complex than what is needed for the soil sample shoe, it provides a basis for the possible functionality of implementing a soft actuator in the prototype.


In considering the final form of the overall shoe, designs from fashion footwear are referenced as examples to convey the concept and house the collection method in the shoe. DEGEN, a fashion company based in Brooklyn, New York created a line of outdoor inspired footwear in 2014 that incorporated elements of hiking boots in an unexpected manner. The result is a shoe that has a platform heels, with flashes of bright color at the heel, trim around the sole, and in the laces. The use of a fur trim and nylon cord gives the shoe an “outdoor” aesthetic, while the choice of color and chunky design of the treads read as more playful. The overall form sends a series of mixed messages due to this combination as a fashionable interpretation of a hiking shoe. The playful manner in which DEGEN approached designing the shoe results in an interesting object that can be utilized in considering the final form for the soil sampling shoe.

The “Jagger Platform Oxford” by design label, Jefferey Campbell presents another approach to footwear design that can be co-opted in the soil sample shoe. In this design, an oxford shoe has been extended at the outsole with a section created out of clear acrylic which creates a storage space for sequins. This seems to be a more humane version of the platform shoes of the 1970’s popular at discos in which clear heels could be filled with gold fish. Parts of the heel for these platform shoes would be removable to place, feed, or even replace the fish as a decorative item within the shoe 🙁 .

By designing a portion of the soil sampling shoe to be clear and transparent, it would allow for the process for collecting the soil sample to be apparent, yet housed within the shoe.  In following the designs for the 1970’s clear heeled shoes, parts of the heel could also be designed to be removable to retrieve the soil sample at the end of a walk.

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