[Density founder here] Hey Animats, sorry it took me all day to get to your list of questions.
> which implies they're selling data to someone else. Who?
Typically our customers are startups who sell to SMBs (coffee shops, bars, restaurants, museums, etc). They charge merchants anywhere between $50-$500/mo/location for some kind of software or service. These are startups that sell POS systems, loyalty software, marketing services, discounts, handle logistics, and delivery.
> There's no privacy policy. No terms of service.
Frankly, it should have been there before launch but since people don't "buy" through our website, we decided to sacrifice legal thoroughness for speed to launch. Maybe a misstep but people seemed okay emailing us their request to order.
> How does the device tell how many people are present based on counting at a doorframe?
Two closely situated, parallel infrared distance sensors. We timestamp spikes in voltage as they come in allowing us to see o...1 = entrance. 1...0 = exit. Giving us the current count in a place.
> Is it counting people passing through the door? Direction?
Yes. Not the line outside. Although we can do line detection and estimate wait times. Yes.
> Is it good enough to estimate the number of people inside by subtracting out counts from in counts?
Yes. It's better than just an estimate.
> Will this work for wide entrances, such as malls? Is this a passive infrared sensor?
No. Our current model maxes out at roughly 90in -- that's with two sensors on either side of a double door facing one another. No it's AIR.
> 98% count accuracy ... If you already have surveillance cameras, you can often use them for counting.
You're right. We're just betting that customer-aversion to facial recognition and surveillance cameras is slowing adoption in the long tail of the market we're after - the various independent merchants and sellers that comprise a city and who are too busy making coffee and food to spend too much time on potential controversial technology. See: http://techcrunch.com/2014/05/29/philz-coffee-drops-euclid-a...
>> Is it good enough to estimate the number of people inside by subtracting out counts from in counts?
> Yes. It's better than just an estimate
What if someone waved their hand in front of it (in a particular direction) in an attempt to subvert it? Couldn't someone trick it into over-reporting or under-reporting the number of people inside?
What if someone is standing idle in front of it (near the door frame) for a few minutes and in the meantime a large number of other people walk in? Will it miss them?
What if two or more people walked in at the same time with no gap between them?
Most importantly: How would the counter ever be able to correct itself from inaccuracies?
> which implies they're selling data to someone else. Who?
Typically our customers are startups who sell to SMBs (coffee shops, bars, restaurants, museums, etc). They charge merchants anywhere between $50-$500/mo/location for some kind of software or service. These are startups that sell POS systems, loyalty software, marketing services, discounts, handle logistics, and delivery.
> There's no privacy policy. No terms of service.
Frankly, it should have been there before launch but since people don't "buy" through our website, we decided to sacrifice legal thoroughness for speed to launch. Maybe a misstep but people seemed okay emailing us their request to order.
> How does the device tell how many people are present based on counting at a doorframe?
Two closely situated, parallel infrared distance sensors. We timestamp spikes in voltage as they come in allowing us to see o...1 = entrance. 1...0 = exit. Giving us the current count in a place.
> Is it counting people passing through the door? Direction?
Yes. Not the line outside. Although we can do line detection and estimate wait times. Yes.
> Is it good enough to estimate the number of people inside by subtracting out counts from in counts?
Yes. It's better than just an estimate.
> Will this work for wide entrances, such as malls? Is this a passive infrared sensor?
No. Our current model maxes out at roughly 90in -- that's with two sensors on either side of a double door facing one another. No it's AIR.
> 98% count accuracy ... If you already have surveillance cameras, you can often use them for counting.
You're right. We're just betting that customer-aversion to facial recognition and surveillance cameras is slowing adoption in the long tail of the market we're after - the various independent merchants and sellers that comprise a city and who are too busy making coffee and food to spend too much time on potential controversial technology. See: http://techcrunch.com/2014/05/29/philz-coffee-drops-euclid-a...
[edit: for readability]