My hackathon submission: Emissions Queen
For DigitalOcean’s 2021 hackathon I set out to create a dashboard for my Emissions station in Duluth, GA.
You can check progress on the publicly accessible website queen.jamesloper.com
I am aiming to build the following features…
- Accounts with ability to link devices
- Webcam view of the interior of the station from Wyze cam
- Screen cast of the emissions computer screen (for diagnostics)
- Call logs for the business phone line (provided by Twilio)
- To determine the exact time the employee opened and closed for the day, I am making an integration with myQ to see when the garage door is open or closed
- To check profit, I am making a scraper for the government provided dashboard website
Development & DigitalOcean
The mongo database will be hosted on DigitalOcean managed MongoDB, and the app will be served by a DigitalOcean droplet. I will run a copy of the development environment on my laptop and then deploy to “production”, but to ease the transition, I will connect my development environment straight to the MongoDB since the beginning. This way I don’t have to maintain two databases.
How will I determine the profit?
Each car that buys an emissions test uses up a “ticket” provided by the government. This is recurring cost for the emissions business, and since each test is a fixed cost, profit can be calculated from just the number of used tickets. If I can scrape the government website, I can calculate profit to a high degree of accuracy.
How will the webcams/streams work?
Depending on the protocol, it can be easy or hard. For the screen cast, it’s easy. I bought a capture card with pass-thru to grab the HDMI signal running to the emissions station screen. A cheap computer running mjpg-streamer exposes the feed as a URL. To embed that in a webpage, all I have to do is put an
<img> tag with the url set as the
src. Any URL pointing to a MJPEG stream can also be embedded into a web page this way.
I also want to get some networked webcams, so I chose Wyze Cam V2. It is capable of serving an RTSP stream, but I had to convert that to something web browsers can view. For this I made an RTSP to MJPEG proxy server. I hand off most of the work to FFMPEG, streaming the output from stdout to the client, however care must be taken to build a buffer and flush it upon each frame.
How are the call logs set up?
When adding a Twilio account, I fetch the historical logs and massage the data into my own format before inserting it into the Mongo DB. From that point, a webhook is enabled so that whenever Twilio gets a phone call, they will make an HTTP call to my REST endpoint. This does mean that while developing the app, I have to make my computer publicly accessible, for example by using ngrok for this.
How will the garage door sensor be set up?
I integrated myQ and will install a smart garage door sensor and will query it every 5 minutes to see if it is up or down.