GoTenna – Send and receive messages even when you don’t have service • Hacker News Board

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

#141

Post by peaton » Sat, Jul 19, 2014, 12:41 PM UTC

peaton wrote: post #28

p4bl0 wrote: post #19

Earlier quoted context omitted.

> The part I think is missing is a connection back to the cell network so that you can give people in more remote locations the ability to text the rest of the world using this as a link. While reading their FAQ I thought of that, and if the API is open sourced or reverse-engineered, it shouldn't be too difficult to write a smartphone application which would act as a relay between to goTenna and the phone network (fo…

It could be a whole lot simpler than this. (And a whole less secure.) In high school I had a server running that scanned email for a keyword and my cellphone number; I didn't have a smartphone. So I texted a keyword and some code to my email. Then my server would read the email, see it contained the keyword, then interpret the rest of the code I sent and execute it. This would be insanely easy (and not too secure) to…

I mean, I know it's not secure. But I had no clue it was down-vote-not-secure!

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

#142

Post by dmm » Sat, Jul 19, 2014, 1:20 PM UTC

calebm wrote: post #70

Potential cool application of GoTenna: communication with a robot without having to pay for a data plan.

Get a ham radio license and you'll have access to lots of spectrum and the ability to use higher power levels, for non-commercial use.

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

#143

Post by somberi » Sat, Jul 19, 2014, 1:28 PM UTC

com2kid wrote: post #134

ismail wrote: post #114

Earlier quoted context omitted.

His assertion is true, i have traveled to 4+ countries in africa, and live in one. I have yet to be without signal in all my travels. You would need to go really remote to find a place without signal. Even sparsely populated areas, backwaters are covered. The reason is communication infrastructure was pretty bad here, hence we leap frogged and mobile is primary means of communication. You also have the other challeng…

> I have yet to be without signal in all my travels. You would need to go really remote to find a place without signal. In contrast, I can travel ~20 minutes outside a major metropolitian area in the US (Seattle) and be without cell service. Heck I often am without cell service when I'm hiking. Then again I'm using a provider (T-Mobile) which is known to only work in metro areas!

I was going to write this part in my original email but wanted to stick to the main concern about use cases. I do live 3-4 months a year in NYC and in my pre-war building, T-mobile has spotty coverage. If I travel to Connecticut, 90 minutes away, there are many spots en-route where I do not get a signal.

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

#144

Post by foolinaround » Sat, Jul 19, 2014, 1:32 PM UTC

if this is available on some kind of rental plan, there is a huge opportunity....

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

#145

Post by ryanmarsh » Sat, Jul 19, 2014, 2:18 PM UTC

Say you are just 1 mile from a friend, at 151Mhz the fresnel zone is 72ft tall. If you are both at equal elevation on flat land then 50% of the signal is going to be absorbed by the ground. How exactly does this scenario work?

Source: I used to build outdoor medium distance (~1mi) wireless data networks with 900Mhz and at 1 mi the fresnel zone is roughly 30ft tall so we would put our antenna 20ft in the air. The awesome thing is we could shoot through a mile of forest but only if 60+% of the fresnel zone was not occluded by the ground.

Edit: I should also add that I would have loved something like this in Iraq. Next to keeping soldiers fed, coordinating with adjacent units (read: not shooting at each other) on foot during a mission is about the biggest challenge there is.

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

#146

Post by wglb » Sat, Jul 19, 2014, 2:44 PM UTC

spacefight wrote: post #118

wglb wrote: post #59

Earlier quoted context omitted.

Ah. We are now at a device that is Bluetooth LE-enabled that works on the 151-154 MHz range from http://www.cnet.com/news/gotenna-creates-cell-network-out-of... So this is essentially a mesh network or at least all independent nodes?

Sounds more like a point to point communication but not a mesh to me.

Yes, and she answered the question in a different thread.

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

#147

Post by njloof » Sat, Jul 19, 2014, 3:32 PM UTC

peaton wrote: post #141

peaton wrote: post #28

Earlier quoted context omitted.

It could be a whole lot simpler than this. (And a whole less secure.) In high school I had a server running that scanned email for a keyword and my cellphone number; I didn't have a smartphone. So I texted a keyword and some code to my email. Then my server would read the email, see it contained the keyword, then interpret the rest of the code I sent and execute it. This would be insanely easy (and not too secure) to…

I mean, I know it's not secure. But I had no clue it was down-vote-not-secure!

They're not downvoting you because it's not secure; they're downvoting you because you don't understand what the product does.

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

#148

Post by spiritplumber » Sat, Jul 19, 2014, 4:50 PM UTC

So my guess is, it's a bluetooth radio and a XBee. Nice? I think? What surprises me is the size of it; I've deployed exactly this (minus the spiffy packaging, admittedly) for barge tracking applications since 2008, and the whole thing ended up being roughly the size of an early 2000s palmtop computer, so good job on that!

The schematic is trivial: a xbee XSC (we used XStreams at the time) with a decent antenna coupled with any serial bluetooth module. The whole thing runs on 3.3V with high tolerances, so a single lithium cell is enough to power it without regulation.

If you can't do meshing for legal reasions, do a transparent blind forward -- for short messages that you don't mind a delay for, it works out well, and the FCC (and the coast guard) have been OK with it. If you want my design contact me at www.f3.to

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

#149

Post by scottshapiro » Sat, Jul 19, 2014, 5:35 PM UTC

I'm most excited for the mountaineering / backcountry application in the short term but as critical mass develops in urban areas, there could be an interesting ecosystem that develops around this even without repeater functionality. Anything from people discovery like Tinder to b2c interaction like OrderAhead could build on top of a comm stack like this.

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

#150

Post by TD-Linux » Sat, Jul 19, 2014, 6:04 PM UTC

ryanmarsh wrote: post #145

Say you are just 1 mile from a friend, at 151Mhz the fresnel zone is 72ft tall. If you are both at equal elevation on flat land then 50% of the signal is going to be absorbed by the ground. How exactly does this scenario work? Source: I used to build outdoor medium distance (~1mi) wireless data networks with 900Mhz and at 1 mi the fresnel zone is roughly 30ft tall so we would put our antenna 20ft in the air. The awes…

The propagation characteristics of VHF are substantially better than 900MHz. I've used voice radios in the VHF band in urban Minneapolis, and have been able to easily surpass a mile of range. I'm surprised they didn't choose a lower frequency still.

In addition, using something like DSSS, a low data rate, and retransmission ability will probably help a lot for this application.