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GoTenna – Send and receive messages even when you don’t have service

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Re: GoTenna – Send and receive messages even when you don’t have service

#101

Post by freels »

daniper wrote: post #96
0xdeadbeefbabe wrote: post #94

@Daniela I hope you aren't exhausted by all these, but X would be cool comments. If not: A walkie-textie would be cool, something less expensive and fragile (as emilv said) than a smartphone with a keyboard instead of a touch screen. Is there a serial interface to gotenna?

I believe you're asking if there's a user interface to goTenna? If so, not in the current device. The UI is your smartphone -- the point is to conform to consumer behavior (i.e. the way you already text on your phone).

For longer periods of outdoor use, a low-power built-in text interface would be useful. Especially if the battery lasts longer than my phone's.

Re: GoTenna – Send and receive messages even when you don’t have service

#102

Post by jrockway »

maxsilver wrote: post #64
emilv wrote: post #24

No voice? That lost all of my interest. So now I need to tap out a message on my expensive, somewhat fragile smartphone with dirty fingers while losing all sight of the road for a minute. Instead of a sturdy walkie-talkie where I can hear the voices of my friends, talk efficiently in real sentences and I can look where I'm going all the time.

I think they are legally forbidden from doing voice by the FCC, on the ultra low band spectrum they're using. (see http://www.fcc.gov/encyclopedia/multi-use-radio-service-murs... search for "you can not make telephone calls") If you want walkie-talkies, there's another entire band dedicated to unlicensed voice calls - http://www.fcc.gov/encyclopedia/family-radio-service-frs You could ask them to make a dual mode devi…

We're calling the "very high frequency" band the "ultra low band" now? Interesting.

Re: GoTenna – Send and receive messages even when you don’t have service

#104

Post by 0xdeadbeefbabe »

daniper wrote: post #96
0xdeadbeefbabe wrote: post #94

@Daniela I hope you aren't exhausted by all these, but X would be cool comments. If not: A walkie-textie would be cool, something less expensive and fragile (as emilv said) than a smartphone with a keyboard instead of a touch screen. Is there a serial interface to gotenna?

I believe you're asking if there's a user interface to goTenna? If so, not in the current device. The UI is your smartphone -- the point is to conform to consumer behavior (i.e. the way you already text on your phone).

Is there an alternative to bluetooth-LE for talking to the gotenna?

Re: GoTenna – Send and receive messages even when you don’t have service

#106

Post by daniper »

jrockway wrote: post #99
daniper wrote: post #84

Earlier quoted context omitted.

We want to do that, but FCC regulations don't enable meshing (currently) on the bands we're using (151-154 MHz, aka the MURS band). We considered releasing a 900 MHz device that the FCC allows to mesh but then you only get, if you're lucky, up to 0.5 km range and it has to be line-of-sight. So we went with MURS because you can get greater range and don't have to be line-of-sight; the propagation characteristics are b…

How often are you getting non-line-of-sight propagation with MURS?

Most of the time. We live in NYC and have gotten anywhere from 0.5 mile to 3.5 miles range here, depending what part of the city you're in. There's nearly no such thing as LOS in a city unless, say, you're in a skyscraper ;)

Re: GoTenna – Send and receive messages even when you don’t have service

#107

Post by sbierwagen »

bengotow wrote: post #100
daniper wrote: post #84

Earlier quoted context omitted.

We want to do that, but FCC regulations don't enable meshing (currently) on the bands we're using (151-154 MHz, aka the MURS band). We considered releasing a 900 MHz device that the FCC allows to mesh but then you only get, if you're lucky, up to 0.5 km range and it has to be line-of-sight. So we went with MURS because you can get greater range and don't have to be line-of-sight; the propagation characteristics are b…

Would it be possible to build a software-level mesh on top of these devices even though they don't officially support meshing? In other words, could someone build an iPhone app that implements some sort of decentralized DNS and routes messages, even though the hardware can't do that on it's own?

CFR 2009 § 95.1311

  MURS stations are prohibited from
  operating as a repeater station or as a
  signal booster. This prohibition in-
  cludes store-and-forward packet oper-
  ation.
http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2...

Pretty clear cut. No packet routing, at all, for any reason, using any method. Doesn't matter if the radio firmware is doing it or if the client is doing it.

(There is a general exemption to all licensing rules, at least in ham radio, in the case of "to provide essential communication needs in connection with the immediate safety of human life and immediate protection of property when normal communication systems are not available." (§97.403 Safety of life and protection of property.) Not terribly applicable in this situation, but a general "the Constitution is not a suicide pact" kinda thing.)

Re: GoTenna – Send and receive messages even when you don’t have service

#108

Post by somberi »

Asking to learn. I travel often all over India and most parts of Africa. I have consistently received cell phone signals in 90% of the places. Local sim cards are easily available and the prices are ~20cents per message. In this context, I wonder the need of such a device. In fact having yet another device to charge is a bigger concern. I can see situations where this is helpful, but I think it is in the minority.

Re: GoTenna – Send and receive messages even when you don’t have service

#109

Post by jimmies »

jmyaunch wrote: post #92
drdaeman wrote: post #69

Earlier quoted context omitted.

For those who care about security, is there an article to read for further details on that?

Hi! I'm on the mobile development team here at goTenna. We're taking advantage of the Bluetooth LE standard encyption with is AES-CCM. More on that here: http://bit.ly/1teKWvG For encrypting the data as it's sent between gotennas we're using 1024 bit RSA. Not sure what level of detail you'd like.. but here are a few things to get you started! RSA itself: http://bit.ly/1kDlTgP Cryptographic Services: http://bit.ly/1te…

So, question: How do you authenticate the person you are trying to message with, i.e. How do I know that I'm sending the message I want to send to (the real) Jason Greengrocer not the FBI pretending to be Jason?

Re: GoTenna – Send and receive messages even when you don’t have service

#110

Post by napoleond »

somberi wrote: post #108

Asking to learn. I travel often all over India and most parts of Africa. I have consistently received cell phone signals in 90% of the places. Local sim cards are easily available and the prices are ~20cents per message. In this context, I wonder the need of such a device. In fact having yet another device to charge is a bigger concern. I can see situations where this is helpful, but I think it is in the minority.

I have not been to Africa or India, but considering that it's easy to find areas of North America without cell phone coverage I find it very difficult to believe your assertion about 90% coverage. Even in cities, it seems from the comments here that there is some appeal to communicating "off the grid" as it were.
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