auraphone: a simple app to collect people's info at events
Hi, I'm Andrew, and I'm building Auraphone, a simple app to collect people's info at events.
I've been a developer for many years and I thought I knew bluetooth well. I was an early employee of the scooter company Bird back in 2017 and wrote a lot of the ios and android bluetooth to "bird brain" logic. But I started a new bluetooth app that is a lot more complex. Imagine a room full of people at a big networking event. Every phone broadcasts a bluetooth service and every phone tries and connects, all at the same time! I'm building this app to bring networking events into the year 2026! We all have bluetooth phones with us, lets use them to solve this who is going to give who their phone number issue. Here is what it does:
You set your name, photo, and what info you want to share. Maybe just your instagram username, maybe your email and linked in too, your choice what to broadcast.
Walk around your networking event and collect all this info from people you are in close range to.
Have a record of everyone you actually meet IRL at this event.
Here is a video demo: Your browser does not support the video tag.
Think of the term "peripheral" as server and "central" as client. Yes there are differences in bluetooth and there are reasons for those terms, but my life got much easier working on this app when I started just thinking client server. So in a room with just two phones, which one is which? It can't be a coin toss. If 50% of the time both phones act as the server and neither client, bad. Or if both phones act as clients, bad. So how do you break the tie? You start up your server AND you act as a client looking for servers to connect to. Just be careful not to connect to yourself!
With bluetooth your server advertises and when you connect it tells you what characteristics it has. Think of characteristics as "endpoints". They are not the same as an http endpoints at all but again my life got easier when I started thinking of them like this. Our app has two characteristics PROFILE_CHAR and PHOTO_CHAR and step one is a client hits PROFILE_CHAR endpoint and gets back json from the other phone with device_id, first_name, photo_hash, instagram and it doesn't have to be json. It could be Protocol Buffers and binary but again, I went with json and yes, easier life.
So with my 200 OK from PROFILE_CHAR endpoint I look at the photo_hash which is a 256 sha from the binary data of the image the user picked. If I have this file already cached, I'm good and I disconnect from this server. If not I hit the PHOTO_CHAR endpoint and get this image data and save as hash.jpg locally. And then I disconnect.
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