Haptic Enhancement of Palpation via viBrotactile feedback

Project team members: Yuxuan Wu, Wentao Ke, Billy Gao & Jeffrey Cai

Give a one-paragraph description/summary of the project, which includes information like the motivation for the project, the goals of the project, and the resulting implementation and success of the project.

Introduction

Explain the motivation for your project in terms of the educational objectives and why your haptic device is an appropriate approach.

Background

Explain the relevant prior work in the field of haptics and provide references. These will likely be different from the references in your project proposal. Make sure to do a thorough literature search on relevant haptic devices/application.

Methods

Provide a detailed description of your project, such that another student from the class could generally re-create your project/experiment from the report if necessary. (You don't need to document every screw, but the design should be clear.) Add images and videos as needed to support the description. You can refer to downloadable drawings and code in the "Files" section (later). You should divide this section into subsections, which can vary depending on your particular project. Here is an example set of subsections:

Hardware Design and Implementation

System Analysis and Control

Demonstration / Application

Results

Describe the results, which may include qualitative responses from users at the open house.

Future Work

Describe how your system could be tested (e.g., through experiments if you have not already done so), how it can be improved, and how it might be applied.

Acknowledgments

Here you can list any individuals or groups who helped you with your project. (e.g., another student in the class, a course assistant, or an especially helpful PRL TA). Optional, so delete this section if you aren't using it.

Files

Code and drawings should be linked here. You should be able to upload these using the Attach command. If you aren't willing to share these data on a public site, please discuss with the instructor. Also, in this section include a link to a file with a list of major components and their approximate costs.

References

List the referenced literature, websites, etc. here.

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Appendix: Project Checkpoints

Checkpoint 1

From the project proposal, the checkpoint goals that we have so far are as follows:

• Order materials: FSR
• Create CAD models for the molds that will be used for silicone phantoms, and potentially 3D print them
• Complete the paper presentation
• Test whether the hand tracking can identify the hand and its position with the ERMs mounted

The goal of ordering FSRs has been met: this is one of them.

We have also successfully prepared the silicone phantoms that will be used.

The paper presentation might or might not happen this week. The hand tracking has been tested, with successful communication between Unity and Arduino using SerialPort.

The current bottleneck that we are facing is regarding the mounting of the FSRs and the ERMs. We realized that it may be difficult to simultaneously mount the FSR and ERM on top of fingers since it would be a really small area and the existence of the FSR may affect the ERM. A potential deviation to solve this problem is by CADing and making a elastomeric ring made of silicone, which could attach the FSR to the front of the finger and the ERM to the back of the finger.

Another unexpected challenge is how to connect the FSRs to power. The solution that we have found is by attaching a soldering iron to the wire and FSR connection.

Checkpoint 2

From the project proposal, the checkpoint goals that we have for this week is as follows:

• Fuse FSR with the ERM by implementing Arduino code to output different vibrational levels based on pressure applied
• Complete and improve hand tracking interface
• Test different vibrational modes for the ERM

For the FSRs, we connected them with the Arduino's 5V and GND using a 10k resistor to form a simple voltage divider setup. We obtain signal from an analog input pin. To allow for two connections with our single 5V pin without using an external breadboard, we soldered together a forked jumper wire. Attach:FSR_setup.jpg Δ From there, we can read the FSR signal, which we threshold into different strength levels to categorize no touch, light touch, and heavy touch.

The ERMs are then connected and to the Arduino by soldering the leads onto stranded wire as well. We tested different strength of vibration correlating to FSR signal strength. For legibility, we used color coded heat shrink and wiring to keep track of which wires are which. Attach:ERM_setup.jpg Δ The hand tracking interface has also been built and can be more intuitively accessed from the user interface. We also compiled it down to an executable so it wouldn't have to run in Unity.

The current bottleneck and challenge is that to put the entire thing together both physically and software wise. Physically it is mainly regarding how to mount it on the users' hands. For instance, the power supply, the glove, the erm, Arduino and FSR placements. From the software side, it is to use the hand tracking system to inform the existing Arduino FSR + ERM setup on whether or not the user's index finger is over a specified tumor area.

The final part of our integration is calibrating how strong the vibration should be and which type of vibrational signal we should use to signal each circumstance (e.g. inside the tumor region or not). That should also combine with a varying level of vibration corresponding to strong/weak pressure.