ECG phone case

A smartphone case that measures a single-lead ECG through printed electrodes, built to test whether everyday objects can do opportunistic heart-health sensing.

shipped2022-06updated 2023-06

Sensing: Single-lead ECG
Front-end: AD8232 (custom PCB)
Electrodes: Conductive printed polymer
Fabrication: FDM print, 3 prototype cases
Evaluation: 12 participants
Context: AIMHealth — Instituto de Telecomunicações

Cardiovascular disease is the leading cause of death worldwide, and most people only get an ECG when something is already wrong. This project asked a smaller question: can an object you already hold all day — a phone — take a usable ECG without you thinking about it?

A phone held in two hands, both index fingers resting on a printed module clamped to the back of the case. — The grip is the measurement. Holding the phone normally puts a finger from each hand on a separate electrode, closing the circuit across the body.

What I built

Three functional prototype cases, designed and 3D-printed (FDM), each with a different electrode arrangement.
Conductive printed-polymer electrodes on the case body, so the reading happens just from how you normally hold the phone.
A new ECG analog front-end based on the AD8232, laid out as a dedicated PCB to replace the bulkier acquisition board used early on.
Signal acquisition, processing and characterisation through the ScientISST API.

The inside of a printed phone case: dark fabric electrode pads at each end, blue wires running to a circuit board with a USB-C connector and a smaller board beside it. — Inside the case. Electrode pads at each end, wired back to the acquisition board and front-end.

Results

Initial experimental evaluation with 12 participants. The work was my first-cycle integrating project (graded 20/20) and was written up as “Towards Opportunistic Electrocardiography (ECG) Sensing in Mobile Devices”, presented at IEEE ENBENG 2023 — see publications.

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