P6: The GaitKeeper

a) Group 6, GARP

b) Alice, Rodrigo, Phil, Gene

c) Our product, the GaitKeeper, is an insole pad that can be inserted into a shoe, and an associated device affixed to the user’s body, that together gather information about the user’s gait for diagnostic purposes.

d) The GaitKeeper can be placed inside a shoe and uses flex/pressure sensor throughout its surface to register data of a user’s gait. This information can be loaded into GUI and users can see a heat map of the pressure on the bottom of their foot changing with time. By making data collection and analysis simple, we intend to allow runners to observe the eccentricities of their own gait without the aid of more expensive devices. We also hope to make the analysis comprehensive enough that a running store operator can use it to better advise a customer or so a sports medicine practitioner can diagnose gait problems in patients. Our experiments are meant to test whether the prototype is simple enough to operate in all our intended use cases and whether the data analysis is comprehensive enough to be worthwhile.

e) The previous writeup can be found here: https://blogs.princeton.edu/humancomputerinterface/2013/04/21/p5-garp/

Here are the changes we have made since P5:

  • The sole is now connected to the Arduino. We have soldered all of the wires to the breadboard.

  • The Arduino and breadboard is now connected to the velcro band that will hold it up.

  • Basic Arduino code has been written to collect data, but it must be connected to a laptop and the data is not fully formatted.

  • The GUI has been tweaked and some of the buttons are now functional. The GUI still does not directly respond to data input from the prototype itself.

f) i. Participants:

The first participant was an employee at a local running store. We are envisioning the GaitKeeper as being used by employees at running stores to help with custom shoe fitting. This participant is one of our potential users and we wanted to see whether the product provided information that previous services have been unable to provide. Our second participant is an avid student runner who has run regularly for years. After hearing about our project, he volunteered to give it a try and provide useful feedback.

Our third participant was a less frequent runner, but tends to run for longer distances.  He had never been to a running store for gait analysis.  We considered him to be a typical running user, and a good indicator of whether the product might have a good market outside of the typical hard running group

ii. Apparatus:

To test the device, we asked users to place the device’s sole into their shoe. The wires go to the back of the sole, up the backside of the shoe and the leg, into the Arduino/Breadboard strapped to the back of the user’s waist. We asked users to put it on themselves to see if they had any trouble placing the sole. Then, we asked them to run around and see whether the device impaired their running in any way. In the case of the first participant, we conducted the test in the local running store’s treadmill. In the case of the other participants, we asked them to run around outside and we followed them with a laptop to collect data.

iii. Tasks:

In the first task (easy) the user looks at the dis­play of a past run to eval­u­ate their gait. They use the com­puter inter­face to exam­ine the heat map from an “ear­lier run” and see if the gait has any eccentricities. In this task, they must be able to recognize if any part of the gait stands out. They must also be able to navigate the data as it changes with time and understand what the information means. Ideally, this step should provide them with actionable intelligence that they can use on their next run.

The sec­ond task (medium) is a user putting on the device for the first time with minimal instruction. This will allow us to understand whether the device is simple enough for the average user to install. This will also allow us to observe whether the placement of wires is inhibiting the usability of the device. If the device is intended for use by the average runner, usability must be a very high priority for us.

Lastly, for the third task (hard), the user goes for a run with the device on. We need to know whether the device is placed in such a way that it will not affect their gait. Feedback on the device’s weight and comfort are very important in this task. To complete this task, the user must plug the device into the com­puter at the end of their run and input the data using the UI.

iv. Procedure:

For the first task, we asked users to look at our mock GUI and explore it. We asked them if they could tell us anything interesting from this example person’s gait. In the second task, we asked them to sit down, install the device’s sole in their shoe to the best of their abilities and strap on the device to their waist. In the last task, we asked the user to run with the device and connect it to a computer for data input.

g) Test Measures

  • In the first task, we simply measured how long it took for the user to make an observation about the person’s gait. We felt that this was directly dependent on the usability of the GUI.

  • In the second task, we measured how long it took for the user to install the device correctly. If it was complicated, we expected the user to take a long time.

  • In the third task, we took sample data from the user. This is important for further development of the heatmap of the GUI.

h) Results and Discussion

The running store employee gave us some very useful feedback. She mentioned that there was a fair amount of bunching of wires at her toes, which was caused by the prototype crumpling as it was put into the shoe. The employee suggested that removing the insole of the shoe might be a good idea. While putting on the device the employee needed help. The velcro straps were difficult to manage alone. Said that it felt similar to a field belt and was an acceptable weight. When the ankle strap was not velcroed the wires flopped around and were almost stepped on. The extra velcro helped, but required our explanation as to how it should be used. When asked about actually using the device she said that she could definitely run for a short amount of time normally, which is all that is needed for a store fitting, but the wires might make going for an actual run with the device difficult.

Our second user did not think the sole’s thickness was uncomfortable. He thought the material was a little sticky and was caught on the adhesive we used to keep the device together. The resizing system of the sole was not used, but the user easily understood its worth and how to potentially use it. He liked the idea of having live feedback on his gait and picked up the GUI easily. Lastly, this user would have preferred to have another sole so he would not have to take it off to measure his other foot.

The third user found the thickness to be acceptable, and did not mention the wires.  When asked, he said that he noticed the feeling of the wires, but did not find them irritable.  He had large feet, and did not make use of the resizing system.  He enjoyed the UI a lot, although he had some difficulty with understanding the forwards/backwards navigation through screens.  He thought the heat map was interesting, but asked for a scale to indicate how much the pressure was (as a science major, he felt that it would be nice to see how much pressure there was).  He had some difficulty interpreting the results, and asked us what sort of shoe we would recommend based on the results which were simulated.

If we can, we would like to make a thinner but more rigid foot pad so as to prevent the amount of bunching in the toe that the first user mentioned. It might also be a good idea to have something to attach the velcro to so that the device does not get tangled up when put away in storage (which happened between tests!). We also hope to complete our interface and tweak a few buttons to make it more understandable.

i) Appendices

This is the demo script: https://docs.google.com/document/d/1lhKJ_DIPd-ytAH5JQWKngYscE7y46kkFy9fNnUEut2c/edit?usp=sharing

This is the user consent form: https://docs.google.com/document/d/1BLw8CSQ7SaTtjhxvk9GwS88LrsquEdwAS13M1yFo5j0/edit?usp=sharing

This is the user questionnaire: https://docs.google.com/document/d/1WERwLGZSJTUI0_e95mPIFo-oXCknQVvQ5wQgmq-U2ZE/edit?usp=sharing


Pictures and videos from testing: