Multichannel Strip Tester

Design Project at Nima Sensor
Project Details

Nima's portable food allergen sensors consist of two parts: a disposable capsule to grind food, extract the allergen, and test for the allergen, and a housing for the capsule with a camera. Antibody-based chemistry on lateral flow strips change color in the presence of the allergen. I redesigned a multichannel version of the consumer device that allows our manufacturers to test multiple strips at once.

In the summer of 2016, I exhaustively tested the original fixture to find sources of variability and potential user error. Using printed calibration strips, I characterized the abilities of the cameras, including read variability, position variability, intensity mapping, and visibility. Furthermore, I prototyped different strip carriers to minimize their effect on chemical development.

In 2017, I redesigned the tester from scratch with input from the mechanical, electrical, and chemistry teams. Instead of using injection molded plastic parts like the consumer device and original fixture, we switched to tooling plate aluminum. The new tester features high precision alignment pins, a camshaft with a microswitch to control the timing of the liquid introduction, an improved strip carrier design, an internal USB hub, and adjustable camera position.

Design for Manufacturability

Designed to minimize material removal, while maintaining functionality. Worked with vendors to redesign sheetmetal part.

Electronic Integration

Selected electronic components—including switches, connectors, LED, and USB hub. Modeled PCB holder given constraints of FPC.

Drawings & Documentation

Created manufacturing drawings and exploded assembly drawings. Worked with vendors and wrote up resource document for internal use.

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