Tidbit

A Compact Optical Rapid Diagnostic Test Reader

In order to address the shortcomings of currently available lateral flow assay reader devices, the Design Thinking process has been used to create the Tidbit, a new optical LFA reader system. Design decisions and refinements have been made based on usability testing and user feedback.

The Tidbit is a standalone device that is wirelessly controlled by any internet-enabled device. Unlike offline reader systems, internet-connected smart devices allow for easy software updates and rapid deployment. The incorporation of a familiar mobile platform results in a system that is easy to use without training and allows greater processing power and network connectivity.

In addition to the benefits of using mobile technology, the standalone device has a dedicated camera separate from the smartphone camera and is connected wirelessly. The optical properties of a smartphone camera, such as focal depth, white balance, and resolution, can vary significantly between different manufacturers and devices. Through use of a static, external camera, these variations do not affect the performance of the LFA reader.

Smartphones and tablets vary extremely in hardware and physical dimensions, with new versions often making old accessories obsolete. The Tidbit is not limited to any physical smart device constraints and can be run from any internet-enabled device that has the necessary app installed.

A single device can also be used by multiple users asynchronously, with each user only having access to the data stored locally on their smartphone or tablet.

The Tidbit has many potential applications in rapid, point-of-care immunoassay-based diagnostics. Because it is portable, low-cost, and simple to use, it has many conceivable uses, including in-home personal health monitoring, use in a clinic, doctor’s office, or pharmacy, and diagnostics in resource-limited settings.

Features
• standalone reader
• connects to any wireless internet-enabled device
• works in conjunction with software
• colored LEDs "count down" strip development
• cassette inserted directly into reader
• asymmetrical design prevents user from inadvertently placing device upside down
• different color pieces allow user to customize reader to their needs or tastes

Hardware
• opaque plastic case isolates internal components from external lights
• fits various cassette designs with repeatable imaging
• 5 MP 1920x1080 CMOS camera with LED ring
• lens minimizes optical path length for sharp image
• controlled by Raspberry Pi A+ SBC
• colored LEDs indicate (1) power, (2) development and analysis progress

Testing procedure
• when device is powered on, a pre-configured wireless network is broadcast for user to connect to
• user selects desired test from a list of options
• corresponding instructions for sample collection and processing including specific pictures verified through human trials
• red and yellow LEDs powered on during development time
• software sends commend for reader to take picture, green LED lit, analysis completed, and result displayed

Custom cassette design
• large, curved end makes it obvious which end should be grabbed and prevents user from inserting too far
• biological sample insertion point on opposite end
• indented text
• color can be varied to match reader