
Show HN: Density – The Heartbeat of a City - jordanmessina
https://itunes.apple.com/us/app/density-heartbeat-city/id955990160
======
jordanmessina
We posted Density a while back when we used mac address tracking
([https://news.ycombinator.com/item?id=7305097](https://news.ycombinator.com/item?id=7305097)).
We've since moved to a wirelessly connected door counter, would love some
feedback.

~~~
colinbartlett
Glad to see the change in methodology! I loved the concept then and still do,
but freaked out at the thought of my MAC address being logged everywhere I go.

~~~
fennecfoxen
This is presumably one reason why Apple has stopped broadcasting your real MAC
address while doing SSID probes, instead randomizing it.

~~~
afar
And Android followed suit. The policy change pretty much bifurcated the
industry. Half died or sold themselves off -
[http://fortune.com/2014/10/29/after-a-blow-from-apple-
nomi-s...](http://fortune.com/2014/10/29/after-a-blow-from-apple-nomi-sells-
to-brickstream/)

The other half doubled down on MAC address tracking tech, arguing that it
still generates meaningful data -
[http://www.euclidanalyticsblog.com/2014/08/beacons-and-wi-
fi...](http://www.euclidanalyticsblog.com/2014/08/beacons-and-wi-fi.html)
Although I've heard they've started to move toward video and facial recog.

We were so small at the time of the announcement last June that we thought...
"Why don't we just build a door counter. How f __ _ing hard could that be? "

...turns out it's like way, really f_ __ing hard.

But here it is -
[http://i.imgur.com/zLUMAG8.jpg?1](http://i.imgur.com/zLUMAG8.jpg?1)

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spott
It would be nice if you let people know before they signed up for an account
what cities you are in...

~~~
bredfield
Good point, definitely something we overlooked. Next build will include that,
as well as the ability to request locations from anywhere.

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dopeboy
This is really cool. My cousin and I had a similar idea but a phone would be
used instead of a custom sensor.

Question - why would a business be OK with broadcasting a "quiet" status?
Wouldn't that reflect poorly on them?

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afar
Can you give me an example of how quiet could be bad?

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PublicEnemy111
Bars, clubs, etc.

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afar
Yeah.

Well, I guess it could be bad if I knew that it was always quiet and therefore
"a drag" (sorry, that was a weird word to use). But I suspect any bar or club
that's reasonably solvent, especially in populous cities, has busy times.

Atm though we only show the traffic right now and notify when something is
triggered, quiet / trending.

Second, I think there are people out there that are not looking for busy bars.
Rather quiet ones. I certainly fall into that category.

We're not in any bars right now, though. I'll get back to you once we have
more data.

~~~
WalterGR
What does "trending" mean? It's... popular right now for being quiet?

It seems like if you had the data, you could build both an app that's marketed
to tell you when places are quiet, and an app that's marketed to tell you when
places are lively.

EDIT: Or do you envision the app to do both? I'm having a hard time squaring
"The Heartbeat of a City" with "Is your favorite place quiet right now? Check
it out in realtime and get notified when it’s convenient to drop by."...

> Second, I think there are people out there that are not looking for busy
> bars. Rather quiet ones. I certainly fall into that category.

I'm curious what the market size is for people looking for quiet public places
vs. lively public places. Is there already a popular app that targets the
latter? Has anyone successfully filled the gap left by Foursquare eliminating
check-ins?

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pash
Very nice! You've taken a big step towards blowing up the assumptions behind
the canonical version [0] of the minority game.

I imagine you're already thinking about how you can enrich your dataset and
provide analysis that will help people solve real problems of consequence.
Parking might be a big one: there's surely money to be made directing drivers
to available public parking spots or showing businesses and real-estate
developers the potential to share parking among uses that are statistically
complementary with respect to parking demand.

And please add Kansas City.

0\.
[http://en.wikipedia.org/wiki/El_Farol_Bar_problem](http://en.wikipedia.org/wiki/El_Farol_Bar_problem)

~~~
afar
Re: Minority report. Yeah, I think there's a space in the future where utility
and privacy don't have to be traded for one another.

There's another cool company doing parking called Parkifi I think.

Someone else mentioned El Farol Bar. If we're causing too many people to show
up or too many to stay home... that would be an awesome problem to have.

Re: Kansas City. Friends with some of the founders / early people over at
Zaarly. We're definitely keeping Kansas City in mind ;)

~~~
pash
Minority games, not Minority Report the movie. :P In game theory, minority
games [0] are a class of games that includes the El Farol Bar problem, a class
in which the payoffs depend on the number of actors who make each choice. For
the most part, the strategic aspect of these games disappears when you have
enough information about who has choosen what so far.

On the parking point—there do seem finally to be some real efforts underway to
gather data about parking availability. At an average cost of about $40,000
per spot in a parking structure and low overall utilization, it's astounding
that it's taken this long for serious attempts to emerge to find ways to
allocate parking more efficiently. In addition to solutions that involve
putting sensors in situ, car-makers are starting to think about how they can
use the ever-expanding array of sensors in their vehicles to map parking
spaces and track their availability [1].

But there are surely other open problems of the same sort that Density's data
could help solve: how many people are jamming into the subway right now, or
how many are at the farmer's market already? In this common sort of situation,
your experience depends on how many other people are doing what you're
contemplating doing, and your behavior will (or would) change with better
information about who's doing what.

Look for those sorts of problems to apply your data to, I'm suggesting. There
might also be opportunities to map demand irrespective of supply. In the
parking situation, for instance, tracking the number of open spaces only gets
you so far; you also want to know how much aggregate demand there is, because
that helps you figure out whether to build more capacity. Second-order
statistics like how many people are checking a location's activity in the app
can help you estimate that sort of thing.

0\. See, e.g., [http://www-f1.ijs.si/~rudi/sola/MinorityGame-
Seminar.pdf](http://www-f1.ijs.si/~rudi/sola/MinorityGame-Seminar.pdf) [PDF]

1\. [http://arstechnica.com/cars/2015/02/remote-valet-mode-and-
re...](http://arstechnica.com/cars/2015/02/remote-valet-mode-and-
revolutionized-parking-fords-smart-mobility/)

~~~
afar
re: Minority Re..port... I've always been bad at reading. Do you know another
example of a minority game? And is it a paradox or just a method of thinking
about game strategy?

Parking - I agree. That one company has a unit that senses the presence of a
battery in a parking spot.

Other open problems - I think your talking about how datasets affect one
another. What's really interesting about that regarding foot traffic is that
there currently isn't a way to know how many people came and went. Which means
it's currently tough to draw connections between how foot traffic might affect
the farmer's market or the subway or the financial district in San Francisco.

Can you explain map demand irrespective of supply?

Checking PDF..

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colinbartlett
Will there be an API for this data to allow business owners to extract it?

One of my clients is building a dashboard that correlates data from various
sources, and this kind of data for physical businesses has long been a dream.

~~~
afar
Yes. Actually, that's our model. We designed the hardware to be cheap enough
to be free (situation dependent) and then we monetize the resulting data.

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Kiro
How is the data collected?

EDIT: Never mind, I didn't see the website where it's explained:
[http://www.density.io/](http://www.density.io/)

Cool product!

~~~
afar
This little guy -
[http://i.imgur.com/zLUMAG8.jpg?1](http://i.imgur.com/zLUMAG8.jpg?1)

Thanks!

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felixthehat
This is great, I was just thinking about a similar idea when I waltzed into my
empty barbers the other day, good luck!

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bobbles
Does this only work with places that have one entrance / exit?

Or could someone rig up say, an entire hospital with this thing and see stuff
like admission / availability of the waiting rooms at nearby ERs?

~~~
afar
Rig up... We can normalize multi-entrance places. Actually Blue Bottle is a
multi-entrance place.

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dreaminvm
Had the same idea a while back whenever I called a restaurant to check the
wait time and it went to voice mail. App looks good, I will try it out this
weekend.

~~~
afar
Local business voicemails are the worst :)

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jjgames
Are there any plans to make the data available via API or maybe offer
webhooks? Would be cool for other folks to mashup this data in various ways.

~~~
jordanmessina
Yup! That's actually our model. I'm really excited to see what people do with
the data

Love the webhooks idea, I can see users hooking into something like ifttt.

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godara123
Good concept! Just curious - can the device accurately track multiple people
(or group) entering / exiting together in one door swing?

~~~
jordanmessina
We're essentially identifying patterns that occur in the voltage readout of
two parallel sensors. Two different people, even if passing through without a
gap, show enough of a difference in their pattern to tell them apart. It
simply takes time to root out all of these granular edge cases.

~~~
godara123
Got it, thanks! Not sure what use cases you have already thought about but
certainly see this being quite handy from a business perspective e.g.
retailers can run real time customized offers/campaigns depending on the
levels of density at their place to engage with the users better and improve
overall experience (of course bottom line as well:)).

~~~
afar
Like "reverse surge pricing"... free coffee until the place gets busy.

~~~
godara123
Exactly or maybe 20% discount on your favorite meal depending on the
store/time of day/user profile etc. This can to some extent ensure the overall
utilization of the retail store and thus profitability are improved. I'm
pretty confident retailers wouldn't mind paying for this on a saas basis or
some other similar model. This will also help on the user acquisition side as
there's now a really cool incentive for downloading/using the app!

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jontro
Nice, however given the name, the triangle logo associated a lot with destiny
the game.
[http://img3.wikia.nocookie.net/__cb20131219001817/destinyped...](http://img3.wikia.nocookie.net/__cb20131219001817/destinypedia/images/4/4e/Trademark-
Confirms-Bungie-Destiny.jpg)

~~~
bredfield
We came after, but they definitely copied us.

Here's how we arrived there: [https://medium.com/@kyle_ohara/simple-is-ing-
hard-91730cf723...](https://medium.com/@kyle_ohara/simple-is-ing-
hard-91730cf72301)

~~~
catmanjan
You call it "the Ingress", and it kind of looks like the Ingress app icon.

~~~
afar
It's hard to create a simple mark these days without bumping up against other
branding. Couple people mentioned Mercedes as well.

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Jordanian
Looks interesting, how do you do this exactly?

~~~
jsprogrammer
Looks like the business has to purchase (proprietary?) hardware to install on-
premises.

Usefulness will depend on whether the location you are interested in has the
required hardware.

~~~
jordanmessina
Generally, we give the hardware away for free (circumstance dependent). We'd
prefer to monetize the data. We don't really want to build a company on $49.99
/ mo. There are a lot of other players in that game. Here's a picture of the
sensors if you're interested:
[http://i.imgur.com/zLUMAG8.jpg?1](http://i.imgur.com/zLUMAG8.jpg?1)

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yellowapple
Neat idea, though the lack of an Android client is disappointing; is one in
the works?

~~~
bredfield
We're focusing on iOS initially, but certainly plan on an Android app.

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shenanigoat
Super cool idea. Best of luck with this.

