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StreetPass Experiments in Tokyo!

by Danny Bivens, James Charlton, Michael Cole, and Minoru Yamaizumi - April 26, 2012, 11:22 pm EDT
Total comments: 19

The Famicast crew push the 3DS StreetPass feature to its limits in downtown Tokyo!

Just how close do you have to be to get a StreetPass? How quickly can you pass someone? All these questions and more are answered in this video feature!

Being huge fans of StreetPass, JC, Danny and Minoru took to downtown Tokyo to push the feature to its limits! To hear the companion podcast, check out episode 10 of the Famicast.

If you like what you hear, why not consider subscribing and listen to our crazy adventures in Japan every month!

If you have the bandwidth, make sure you watch this video fullscreen in high quality!

StreetPass a go-go baby!

All music is copyrighted to Nintendo, and is included under fair use protection.


supergttApril 27, 2012

I see you say to watch in hd, but the quality thing only goes up to 480.

famicomplicatedJames Charlton, Associate Editor (Japan)April 27, 2012

Quote from: supergtt

I see you say to watch in hd, but the quality thing only goes up to 480.

Wii HD baby!  ;)  (fixed)

oohhboyHong Hang Ho, Staff AlumnusApril 27, 2012

That has to be some of the most unscientific and hilariously poorly planned "experiments" I have ever seen. During the speed tests I would imagine one of you trying to run to a percentage of the speed of light to see if red shift would have an effect on street passing. This is a science/nerd joke.

The speed test could have been done without any speed by varying the window of time they can communicate with each other. Once you find the average time, you can calculate the passing speed for a connection while taking distance into account. At maximum range velocity would be zero to get a connection. At near zero range the velocity would be the 2x max distance divided by time.

Using the formula for a chord found here gives us the formula to find the velocity at an distance from the center.


r  is the radius of the circle
d  is the perpendicular distance from the chord to the circle center
T is the average connection time

There is also no difference between horizontal distance or vertical distances. The orientation of the antennae may have an effect on the distance as two antennae of the same orientation have better ability to pick each others signal than if orientated 90 degrees to each other. You could have simulated going "vertical" by changing the orientation of one of the 3DSs.

The reason as to why you can't street pass with a train is not because it is going too fast, the metal is in the way, proven by the elevator. Also local interference in a dense urban area is going to outright flood the radio waves decreasing the range of a street pass. You guys should have stayed in the park as it would have allowed you to have some measure of control with that one variable.

Unfortunately real science isn't sexy. That's why your video game reviewers. Definitely an "A" for effort.

geoApril 27, 2012

Considering you have to wait 5 hours between experiments, they did a pretty good job.  You can only test so often unless you have a horde of 3DSes.  I'd love to see a collaborative effort with some controls and multiple experiments.  Maybe interview some nintendo people and see if they cough up some of the details.

Padawan of WinduApril 27, 2012

I know for a fact that you can get streetpasses from floors above you.  I get streetpasses from a little girl that only stays with her dad every other weekend in our apartment building.  I also wish they had done an experiment with one person sitting, and one person running past, instead of just both running.  And maybe a subway's windows would allow streetpass if it were going slow enough, unlike the elevator experiment, where it's enclosed.

oohhboyHong Hang Ho, Staff AlumnusApril 27, 2012

You basically only need two experiments. One for distance, one for time. Repeat until a useful average can be found. Do some lite maths and you have a yourself an empirical model of how street pass works. A sample size of one would get you a result, meaning 10 hours required to run both experiments once, just it won't produce very good numbers, but it would be a result.

As I said before, real science isn't sexy and you can't film it most of the time. Admittedly knowing the science behind something does spoil shows like Mythbusters for me a lot of the time especially when it deals with hard physics like gravity. But then I get to see the show from another angle where I get as surprised as the hosts when the experiment goes the other way. They, like me have already done the maths and the thought experiments. A "wrong" result is even better than a "right" result assuming an experiment was done right as it challenges your preconceived notions.

An interview would be cool, since they would have one set of hard numbers you could use. The time window would be a technical one based on based on power use. I don't think the radio listens and broadcasts all the time for street pass, so they could tell you the minimum programmed time between activations. They also could tell you how long it really takes to transmit the tiny amount of data (Likely to be negligible). From there you can work out best and worse case situations, then take the average.

It would be an experiment as to how smooth talking the Famicast is when dealing with Nintendo

leahsdadApril 27, 2012

Yeah, this was a very unscientific process that you guys went through.  Personally, I think you should return that grant money that you received and completely rethink the paper that you're planning to publish.  I don't think any journal worth its paper would publish your findings.  And how did you expect the other research teams around the world that are also engaged in Streetpass studies were supposed to replicate your experiment to corroborate your results?  This is so typical.  I bet your had your grad students plan the whole thing for you, didn't you? 

P.S.  Seriously, has anyone every tried googling "How Streetpass works" or "what is the range of streetpass?"  No one out there knows anything concrete, like NCL is Willy Wonka's chocolate factory and Streetpass is the everlasting gobstopper that no one knows the science of.  Kudos to the Famicast crew for pretty much creating more knowledge about this than anyone else has on the entire internet.  The ENTIRE INTERNET.

nhainesApril 27, 2012

Yes, but the problem is that their experiments didn't result in knowing anything concrete either.

All you really need is a wifi signal strength analyzer and a 3DS and you can probably determine how often the 3DSes broadcast when they're at the home screen in sleep mode.  From there you know how often they're sending StreetPass data.

Then you turn on two and measure the time they're transmitting, and you have your answers as to how often they look for StreetPass data and how long it takes to complete a StreetPass.  Finding out how fast you can go past each other and still StreetPass is simple maths at that point.

Aside: I'm not sure why nobody can figure out why different games have different StreetPass limits.  The game has to register itself with the 3DS before it can StreetPass, and only 10 games can be active in StreetPass at once.  It's obvious that the 3DS is simply storing StreetPass data in system memory and that's the constraint for the limit.  Therefore it is logical to assume that some games share more data in StreetPass mode and have less individual events, whereas other games use very little data and can store many StreetPass events.

CericApril 27, 2012

I personally know I can street pass a demo 3DS unit inside a Gamestop from my car driving by at about 5 miles per hour.

oohhboyHong Hang Ho, Staff AlumnusApril 27, 2012

They did have one piece of sort of useful data. Distance. Unfortunately they didn't measure it, start from outside of maximum range, have a method of approach, nor did they control all controllable variables like orientation or have more than one data point.

Do keep in mind I was designing something with a budget of Zero dollars/Yen in mind. An Analyzer would be great, easy solution, but costs money and access they don't have. There is also the technical expertise factor.

I am sorry I am coming off real harsh about this video, it's just that I couldn't stop laughing while watching it. It was like watching a cross between scientific Jackass and Ghost hunter. I don't blame them. They have shown plenty of enthusiasm in the pursuit of knowledge that should be encouraged. I just hope next time they put more critical thought into it, so next time they will have some useful data.

NintendadApril 27, 2012

First, you guys look nothing like I envisioned after listening to several episodes of the Famicast. Second, while I agree there was a ton of variables to the experiments, it's by far the most comprehensive information I've seen about StreetPassing. I found it to be entertaining.

I think there is a lot of variables at play with the 3DS's themselves. I have a 3DS and so does my daughter. I've pulled up in front of her house to pick her up and watched my 3DS light turn green before she even comes out of the house. Another time, I picked her up, went to a restaurant, and looked at my 3DS to see the light was not on. Then, about 10 minutes later I checked it and it was green with her tag. So it literally took 25+ minutes to register.

I also walk a lot along a busy street in which the speed limit is 35mph. I have got street passes from people driving past me in a car (maybe one every other week or so). I've also noticed I'm much more app to tag someone's 3DS in which I get their game information (Mario Kart 7, Mario 3DS Land tags) but not get the Street Pass Mii. I realize some may have not set up their 3DS's to make the Street Pass but it has happened so frequently when I'm walking I think I'm losing their connection before the Mii is passed between systems.

You'd think there would be more information out there regarding experiments like this. I didn't realize there was a 5 hour buffer between Street Passes so that makes it tough to test.

leahsdadApril 27, 2012

Quote from: Nintendad

I also walk a lot along a busy street in which the speed limit is 35mph. I have got street passes from people driving past me in a car (maybe one every other week or so). I've also noticed I'm much more app to tag someone's 3DS in which I get their game information (Mario 3D Kart, Mario 3DS Land tags) but not get the Street Pass Mii. I realize some may have not set up their 3DS's to make the Street Pass but it has happened so frequently when I'm walking I think I'm losing their connection before the Mii is passed between systems.

You'd think there would be more information out there regarding experiments like this. I didn't realize there was a 5 hour buffer between Street Passes so that makes it tough to test.

I have heard other people claim that there is definitely a buffer, but no one seems to be completely sure how long the buffer time is, or if there is one at all.  I heard theories that this buffer may be intentional, as a security measure (I guess to ward off child predators from using the Streetpass feature somehow...??).

I'm particularly interested in how long you have to be in range of someone for a Streetpass to occur.  This would also apply to speed and distance.  But you're right, there would be a lot of variables.  Do many Wifi signals in the vicinity affect how quickly Streetpass would occur?  Atmospheric conditions? 

Also, does the amount of data being exchanged affect the Streetpass?  Does all the data get exchanged at once, or are they in some kind of order (Mii stuff first, then games?)  It sounds like from Nintendad's experience that game info gets exchanged first. 

I realize that a lot of this information will never be known until some GeoSpud-like person hacks a 3DS, is able to run code, and look at how the system exchanges data.  And while most people would cheer such an act on in the interests of understanding how Streetpass works, I'm just a little afraid of what some malicious people would do if they were able to run their own code on a 3DS.  Imagine what a Streetpass virus would be like.

famicomplicatedJames Charlton, Associate Editor (Japan)April 27, 2012

Some things to note:
*We were only paid $50,000 from Havard and ¥20,000,000 from Nintendo to make this video.
*The mobile testing chamber used to measure radio waves for NASA was booked out that weekend.
*We'd forgotten to bring our scientific calculators that day.

However we did use four 3DS's to do these "tests" (maybe our use of "experiment" has offended some) meaning we did all 5 in one afternoon. We figured the would be a least a good start and easiest to try.

This was for fun, but also  to hopefully inspire people to start experimenting with Streetpass, there is SO much more we can do, as suggested by others in the thread! How many games you have activated in S'Pass etc

So keep us up to date with your daily StreetPass adventures, there are obviously so many things that can affect the S'Pass, we might never fully know everything, but if we collaborate we can shine a light on some things at least.

Got a friend with a 3DS? Got another with a camera?
Post and share your results!

If you have any suggestions of some realistic and doable tests we could do if we were to attempt a "Part 2", by all means tell us!
If it involves buying any scientific equipment or PHD-level scientific knowledge, well...I'd try those out yourself first! :P:

Chocobo_RiderApril 28, 2012

I will watch this tomorrow! Can't wait!!!

Great job on this guys.  Very interesting, and should spark some discussion and further experimentation in terms of how StreetPass actually works.

Chocobo_RiderApril 28, 2012

Just watched it.  Loved it.  I want to move to Japan and be a famicast production crewman!

... unfortunately, life has other plans  :-\

ivanincubusApril 30, 2012

hey guys, great video. I happen to travel to mexico Quite frequently(since im from texas and have relatives living across the border), and when coming back I have to wait in my car for about an hour  for U.S. customs to let me back into the country. this creates a great streetpass scenario. I used to get a few every now and then, but now i stretpass like johny at pax east!

famicomplicatedJames Charlton, Associate Editor (Japan)May 01, 2012

We don't really have access to a car here, but if anyone out there wants to film some 3DS-in-car action be sure to link us up with your results!
I wanna know:
*Driving at 5mph passed a guy sitting at the bus top, then maybe increase it to 10mph?
*Two cars driving full speed down a motorway side-by-side or a few metres behind (would that interference hinder it?)
I remember some staff members doing Pictochat that way, maybe it would work!

UltraClaytonMay 01, 2012

I have to say I do think there was one time I StreetPassed someone on the road. I got on a school bus and checked if I had any StreetPasses, and I had none. about 20 minutes later, I got a StreetPass out of nowhere. My only explanation was it was from another car. No one else on the bus had a 3DS. We were on the freeway so I would think a passing car or nearby car could get close enough for a long enough time to StreetPass.

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