Amulete: Smart Belt for Endometriosis
Full engineering process for Amulete, a smart garment concept designed to support people living with endometriosis. The system pairs with a heated skirt capable of delivering up to 140°F of targeted warmth to help relieve symptoms. Through a Bluetooth-connected mobile app, users can control heating levels, while built-in sensors track temperature and help prevent overheating.
Team
Josheta SrinivasanChristine Lai
Role
DesignerEngineer
Timeline
Jan 2025 –Mar 2025
Tools
Fusion EAGLEFusion 360
BACKGROUND
Designed for Josheta, my mentor and one of my biggest sources of inspiration. We bonded through a shared passion for building solutions in the femtech space. In our conversations, Josheta spoke about how difficult it can be to manage endometriosis and severe cramps while out in public. That insight pushed us to explore heat therapy that feels accessible, discreet, and wearable—without relying on bulky portable heaters. That exploration became Amulete.
PROBLEM
Around 190 million women globally are affected with endometriosis, a condition where the uterine lining grows outside of the uterus causing extreme pelvic pain. When these women have their period, the pain is constant for the entirety of their cycle and studies show that at its most intense, period pains can be almost equivalent to the pain you experience during a heart attack. This impacts so much of the women’s daily lives and impacts their ability to function normally.
There are many ways to remedy the pain including pain relievers and over the counter medicine, but most people who experience endometriosis say that even these don’t work for the pain. On top of that, taking too many pain relievers lead to damage in the liver, stomach problems, and internal bleeding.
What does help endo is heat. Very warm heat applied to the pelvic area to relax the muscles and provide relief to the period pains. The problem is, women don'`t want to be carrying around a hot water bottle with them everywhere they go. There are portable heating pads in the market right now, but they are very clunky and big - not seamless and don'`t blend well with an outfit.
THE PLAN
Diagram of Work Breakdown Structure, I have separated the product planning into five main sections: Electronics Development, PCB Design, printing the 3D Amulete Casing, Garment Development, Software Development, and Testing / Iterating.

Electronics Development
Starting off with Arduino and more clunky electronics to test the connections, prioritizing the function of the product first.
PCB Design
Designing the PCB to efficiently manage power, integrating battery protection, voltage regulation, and MOSFET-based PWM control for safe and adjustable heating. The layout would be careful of thermal safety and seamless integration with the Amulete enclosure.
3D Amulete Casing
Printing with 3D PLA filament and spray painting it with a metal finish for the MVP and potentially moving to an Amulete model. Modeling with SolidWorks to encase the battery and electronics.
Garment Development
Experimenting with different fabrics and choosing materials that would house the electronics layer + Sewing/cutting
Software Development
Programming the PCB with C and making an MVP of the app that connects to the skirt using React Native.
Testing / Iterating
Iterating upon how the technology integrates into the fabric and experimenting with component placement and testing if the garment is waterproof during laundry.
Bill of Materials
| Qty | Value | Device | Footprint Name | Parts | Detailed Description | Purchase Link |
|---|---|---|---|---|---|---|
| 1 | ADAFRUIT_ESP32_FEATHER | ADAFRUIT_ESP32_FEATHER | ADAFRUIT_ESP32_FEATHER | ESP32 Feather Board | Microcontroller handling Bluetooth and heating control | Link |
| 1 | JSTPH2 | LiPo Battery Connector | JSTPH2 | 2-Pin JST-PH Connector | For connecting Li-Po battery to Feather board | Link |
| 1 | LIPO_3.7V_5000MAH | Li-Po Battery | LIPO_CELL | Li-Po Battery | 3.7V 5000mAh rechargeable battery with JST-PH connector | Link |
| 1 | - | Boost Converter | — | Pololu Boost Regulator | Boosts 3.7V to 9V to power heating tape | Link |
| 1 | - | Heating | — | Adafruit Electrical Heating Pad | Heating Pad | Link |
| 1 | - | Skirt | — | Spandex Jersey | Fabric | Link |
FABRICATION PROCESS
Full Requirement Doc: Amulete Requirement Document
Github: Amulete Code
PCB Fabrication

PCB Schematic

PCB Brd
3D Modeling Enclosure

Enclosure 3D Model on Fusion360

3D printing enclosure
Soldering
Soldering components to PCB
Soldering aerial view
Sucking solder
Developing Bluetooth Connectivity + Assembly

Bluetooth Connectivity

Phone Output

Assembled Amulete Enclosure + PCB
DEMO
REFLECTION
Most Challenging
Precisely Soldering Along the Traces
- Required careful control to avoid solder bridges
- Had to ensure electrical continuity only at the designated trace paths
- One small mistake could lead to shorts or broken connectionsy
Lessons Learned
Slow down and Pay Attention to the Details
- I printed the PCB 6 times — most of those errors were avoidable, if I were to solder carefully
Most Satisfying
Getting Everything to work in harmony
- Successfully achieving proper connections after troubleshooting
- Watching everything power on and respond exactly as intended was incredibly rewarding