Density (http://www.density.io) | San Francisco, CA, USA / Syracuse, NY, USA | Full Time

Open Positions

- Eng: Embedded Systems Engineer (Embedded Linux)

- Eng: Front End Engineer (React)

- Admin: Office Operations

- Ops: Strategic Sourcing Manager

- Ops: New Product Introduction Program Manager

We offer competitive salary and stock options. Contact jobs@density.io and include the information you think is relevant.

At Density, we build a small sensor that measures how busy a location is in realtime. Customers mount the unit above a doorway, connect it to power and WiFi, and use our API to access how many people have visited. When we announced what we were doing last summer, we hoped technical companies and developers would reach out. They did. But so too did hundreds of others from all around the world and in completely different markets. Some with expansive, two thousand location networks, others asking for a few hundred, and many with just one set of doors they deeply cared about: airlines, SMBs, Fortune 500s, startups, ad agencies, country transit systems, etc.

We’ve since learned that “human load balancing” is a widespread and unsolved problem. Today, we believe our platform may democratize access to a fundamental piece of information that has simply been uncollected and lost.

From the ReCode article: "Twitter and Square both declined to comment."

Now it's official

It can! To accomplish this there'd need to be a custom iPhone app for a location and everyone that goes in would have to have the application installed and have their bluetooth turned on.

That was a quote from the movie Taxi Driver, as is all the italicized text in the article...

I did the Show HN. The original title was "Density Platform" because we just revealed our new sensors and the public facing API. Not sure why a mod changed it.

This isn't in the pipeline but shoot us an email and maybe we can work something out: team@density.io

Right, the increase was on the webpages that included Density to show seating capacity.

I also find this particularly confusing/misleading - since you deal mainly with physical locations (often called sites by owners), using the word "site" instead of "web traffic" seems odd. Also, listing a web based metric as large as 950% without any type of time interval really kills the true significance of that metric.

My favorite statistic: 73.6% of all statistics are made up.

My 2nd favorite: 950% of 0 is 0.

Oh, that wasn't clear at all.

Yeah. We could and will clear that up.

Is that sustained website growth since then? Also can you make that distinction clearer on the site? It's definitely misleading some people.

We’re using infrared sensors. Both the emitter and detector are on a single sensor, so we only affix our hardware to one side of a doorframe. This is different than break beam which requires hardware on each side of a door.

How much accuracy do you lose when people are dressed up in full winter gear?

When you would wear metamaterial stealth suits maybe you can avoid being detected by our IR sensors, we're curious as to what you have available!

Incredibly accurate and anonymous seem to be at tension here. A discussion on your signal processing would be illuminating.

We made our own AIR door counter, composed of a few distance sensors. It can tell us in which direction a person is passing, and gives a distance profile that we process to distinguish individual people. Technically, we measure your circumference to some degree, but you might agree that is far from enough to compromise your anonimity.

AIR being active infrared as opposed to passive (or a particular waveband)?

Anonymity is a more interesting problem than "can distance sensors uniquely identify a passerby among 500M North Americans" as your reply implies. What if you are the roundest or tiniest person in town? All the sudden you are uniquely identifiable.

You're early in development, and I bet whoever did the circumference estimation has more in mind. I imagine you could make a good estimation of a person's height from your data: whether the profile sees knees hips or hands. Can you identify the asymmetric waist bulge of a CHL carrier? Does your infrared band penetrate polyesters but not cotton? I hope the reader's feature-vector blood is flowing at this point.

Your page needs to have way more formalization around the concept of anonymity (outside of the registration required area) for me to feel that you are appreciating the problem from an engineering perspective and not a marketing one.

Gotcha, yeah that makes sense, as it'd cut down the number of individual packages you'd need for the system.

Thank you! Fixing it now.

How does the solution handle multi-ingress/egress points?

Could it be used for tracking population leaving during a fire drill? As often this is the first question asked by first responders, "Is anyone still inside?"

So that's a really novel idea. It would be incredible to tell a first responder how many people we think are inside... accurately.

We just do installs at each entrance and then normalize.

This would be a reallly cool application if PIR's were capable of counting "horde" foot traffic, like a giant mass of people streaming out of a door during an alarm. I don't think that something like a PIR could handle that number of people, since it's just the single beam.

I really like you, for some reason. I think it's your green handle.

Thats not a protocol. Is it subgigahertz with Simplicity, or Zigbee or ...etc, etc.