Brian Davidson

Trimetric is a realtime visualization of the Trimet transit system in Portland, OR, using the GTFS feeds provided for developers by Trimet. It downloads the static GTFS feeds periodically and ingests them into the local Postgres database, for querying later using PostGIS. Realtime GTFS data, such as vehicle position and trip updates, are polled and produced into Kafka, where it is consumed by other workers.

The front end is a responsive web app built in React and uses Mapbox and deck.gl to render the map and icon layers. When zoomed in, Trimetric shows you a dynamic list of the stops that are visible on screen, which you can click to see upcoming arrivals.

You can view Trimetric online at: https://trimetric.briand.co

Trimetric Mobile provides hybrid Android and iOS companion apps to the web based Trimetric project. The apps are built using React Native, with a shared codebase. The map is rendered using Mapbox, similar to the web project, although this implementation uses the React Native Mapbox GL library.

These apps offer a more natural user interface for touch based devices and provide additional features, such as displaying the route lines for upcoming arrivals. The apps connect to the same Go backend as the web app to stream realtime data and cache static data locally on the device.

You can download the app on Google Play or the iOS App Store, and the source code can be found on GitHub.

A standalone Go application that runs on the Hearing Hotspot server and provides a stats interface (written in TypeScript and Angular) that the customer can use to view usage information for the device. It provides a real-time view of the number of connected users, with historical graphs and breakdowns by time range and platform.

The T45NET is a network controlled assistive listening transmitter. It takes an external audio source and transmits it over FM to a receiver (usually a portable device carried by the users). It has an internal web dashboard that can be used to configure and monitor the device. The dashboard communicates with the device via a JSON API.

I built the mobile apps for Android and iOS, and a dashboard that is embedded on the device itself. The dashboard is written in HTML/CSS/JS. Due to the severe space limitations of the device, I couldn’t use much in the way of frameworks, and the JavaScript and CSS was almost entirely home rolled. The mobile apps are hybrid apps written in PhoneGap, and share much of their code with the dashboard.

I also built a standalone dashboard (with its own Ruby server) that used the same APIs that the mobile apps used, to allow a large number of users to interact with a single T45NET device (without overloading the device), and to allow a single user to manage multiple T45NET devices from one dashboard.

The Hearing Hotspot is a device that multicasts live audio over wi-fi. It’s used by conferences, gyms, bars, airports — any place where someone is showing video and wants people to be able to listen to the audio from their own mobile devices. Users run an app on their iOS or Android devices, and a server can broadcast live audio (from a source like TV, radio, etc.) to thousands of clients at once. This is possible because it uses multicast networking, which is much more efficient than a traditional model where the server is maintaining individual connections to each client and sending them data separately.

I built the product website, and worked on the admin dashboard customers use to manage their hearing hotspot devices. The dashboard allows customers to edit the labels for their audio channels, and edit the information that appears in the mobile apps on user devices (company information, background images, ads, links, etc.). The dashboard is hosted centrally by Williams Sound, and the hearing hotspot devices pull down the configurations on the fly via an HTTP API.

The corporate website for Williams Sound has a responsive design that works equally well on desktop or mobile devices, with styles written in Less. The site is always changing, and working on it means collaborating with the design and marketing departments to create and update pages for products and other content. I also worked heavily with a localization firm to translate the site in two other languages. The site also has a backend to manage products, sales territories, and downloadable assets.