"Cellular connectivity is provided by the SM5100B GSM Module...". Meh. No way a DYI. It's like you assemble your desktop PC from pieces like motherboard and power supply and say that you built a DYI PC.
As the person who made the phone, I think this is an interesting question.
Do we say that Apple doesn't build computers themselves because they buy the CPU from Intel? Or because they use Qualcomm transceivers (and lots of other off-the-shelf components) in their phones? On the other hand, we probably wouldn't say someone made a phone if they just put it into a different enclosure.
I can say that I spent a lot of time selecting all the components, putting together the schematic, routing the board, and writing the UI software. (All of that took a lot longer than laser-cutting the case.) Of course, it probably took a lot more work than that to create the GSM module. But that's also true of the microcontroller I'm using, the LCD, even the battery. Just about everything is built on top of the work of others (see the Toaster Project for an example of how hard it is to do otherwise).
Interestingly, this critique hasn't really come up from the people I've worked with to build the phone. I explain the function of the GSM module (and the rest of the components) but after putting it all together, people don't seem to think of the phone as just a box for the module -- in part, I'd argue, because they realize how many other things are in there too.
Again, though, there's a fundamental question here that I'm trying to explore with my research: what does it mean to do it for yourself?
Don't listen to these people. This argument is old, and tired.
It's the same as:
"I don't code python, that isn't a real language, it does everything for you, unlike C!"
Really? Does everything for you? Good to know that you built your own transistors from scratch via materials that you mined out of the ground, while naked, using only tools that you scavenged out of the forest, and that you came up with the entire process yourself.
True, but PC assembly vs black box computers spawned an entire industry and and have kept component prices low even for end consumers. I had to replace a hard disk recently and am still bemused by my ability to purchase a new server-grade 2TB drive for $125.
I'm a former DIY Cellphone hacker, and builder of several commercial GSM telemetry systems... Even using an integrated module you'll still run into FCC certification issues. Then there's PTCRB certs, CTIA membership, and carrier certifications. Of course even if you have the money you'll realize that all of these things have been done to the integrated module (which you haven't modified) before it ever hit the market.
"Wait, you said you programmed this yourself, but I noticed that you're using c and some c libraries. That's not DIY! And you're using a compiler. That's also cheating! You should really be flicking toggle switches and pushing a button to enter the hex values directly."
Who cares, phones are interesting to people because they enable communication with others. Phone projects like this are interesting because they enable people who wouldn't ordinarily be able to build a cell phone, to build a cell phone.
I did a quick peek at their electronics schematics. Well, believe it or not, but it looks like designing a laser-cut custom wooden case for this phone took much more effort than the electronics part. So, returning to my analogy: you are building a DYI PC because you laser-cut a custom case for the off-the-shelf parts you purchased. If this is the level of DYI to be amazed of on this site, I'm completely confused.
I posted this not so much because I was amazed by the thing itself or thought it represented some pinnacle of "true" DIY, but more so because I like the idea of making things that were once far out of reach of anyone but serious hackers into something that a broader collection of people could feasibly tackle. It isn't quite there yet, but it is due to people like this that it will be, one day. You could nitpick all day about how most anything isn't truly DIY unless you mine/refine all your own materials and create your electronics from first principles, but that starts to get a bit silly.
More generally, I am a believer in the idea I first read from Clay Shirky that as more people get involved in an area average quality goes down but innovation goes up a lot as you get lots of people trying lots of new things, which in the end is only goodness. Except, perhaps, for those that prefered it remain elite so they could feel special (not saying this is you, but I see this attitude in a lot of pioneers in areas that later become more mainstream).
Totally possible. I've built telemetry systems out of this family of devices. However rather than using the AT TCP stack, you're much better using the standard GPRS PPP mechanism that most USB cell modems use so that you can use your chip's or OS's TCP stack instead.
[EDIT:] It's been a while, but Telit was also pushing their embedded python interpreter pretty hard back when I was into all of this. I had need for an embedded micro for other parts of my application so I never bothered too much with it, but it looked pretty interesting.
I don't think this is about an individual's amazing engineering effort so much as it's about the ability for an individual to leverage the amazing engineering efforts of huge teams in the form of low-cost, low-quantity integrated modules.
Same with osmocom.org (their site is down atm. though), but they've among many things built a GSM base band stack, running on real phones.
While certainly not intended for every day use, it's very handy to atleast have something for research and learning where you can access all the protocol layers. Just imagine the TCP/IP world if no one could ever send/receive any packet/frame/bits/protocol below the application layer.(i.e. TCP/UDP/IP/Ethernet was just a black box on a silicon chip).
That's basically the GSM world, at least until the osmocom guys made their own stack, running on cheap and old nokia phones.
This is what I love about living in the future (and HN). I live just north of Seattle, I read a story last night about this project in a magazine from the UK (New Scientist). I posted it to a website in California and the project creator, from Massachusetts, responded and it turns out he has had an account here for over 4 years.
I know PG wrote an essay about how certain cities act as magnets for smart people looking to change the world, and how it is advantageous for companies to set up in those cities. That always struck me as a rather antiquated system (though I don't deny it is currently true) and I always wondered how long it will be before that changes. The idea that to properly collaborate we have to arrange such that all of our molecules inhabit a relatively small geographic area just seems silly. Things like this really make me appreciate the power of the internet to connect people and propagate interesting ideas (instead of just memes). Makes me think that before I die the idea of necessary co-location in order for people to collaborate effectively will be a bygone notion. I would welcome that change.
How's the reception and microphone quality? (i.e. how well does the sound of your voice on the phone compare to say an iPhone or Nokia-era candybar phone?)
Also, great work! I looked into building a cell phone before, and it's an awesome amount of work.
It apparently sounds pretty good, according to the people I've called. The reception seems pretty standard, although I don't actually display signal strength in the interface yet so I'm not totally sure.
My grandmother has pretty bad arthritis. No major carrier sells a handset that is easy for my grandmother to manage. It may be time to put one together for her.
In the UK they sell a range of mobile phones with big buttons, particularly for the elderly. Basic features on it only of course, but that's probably all they will use anyway.
Basic features on it only of course, but that's probably all they will use anyway.
That's a rather self-fulfilling attitude, and I hope that we as an industry try harder really soon.
My parents are in their late 60s, and are quite good with computers. I'm working on a side project with a woman in her eighties who started programming during the Eisenhower administration. And I know a number of tech folks in their 40s or 50s who have one form or another of muscular or nervous problem. None of them should have to compromise on features just because they want a more accessible device.
I didn't mean it in that sense, my parent are both pretty old but have no idea about tech. For them this phone was perfect, since all they wanted to do was make calls, a green button to make the call and a red button to finish the call.
With a phone like this, there has to be a compromise somewhere. By basic features I meant by today's smartphone standard, you are never going to get that to that level with an LCD screen and button taking up all the phone real estate. It is really only going to be possible for calls and SMS messages.
Of course, if they need a smartphone with big "buttons" and a big screen then you could always buy them the Samsung Galaxy Fucking Note
How to shrink a basestation into a Raspberry Pi. http://www.youtube.com/watch?v=GCcKgrzbix4 It's not the handset, but rather the basestation. But the concept is similar. I saw this working. It works. And there are open-source versions of the handset software too, although not as mature as OpenBTS.
Actually what these guys don't mention is that the Raspberry Pi is plugged into a relatively huge USRP, because that kind of blows their whole "Look how tiny it is" PR out of the water.
The host part of OpenBTS is not just call control(Freeswitch or Asterisk provides most of the call control part).
OpenBTS is a software defined radio and really does most of the processing in software. The USRP provides the radio interface, up/down conversion between baseband and carrier frequencies and the analog/digital conversion.
The USRP just sends/receives those samples without caring or knowing about GSM. Samples are processed in software on the host, where the GSM stack is implemented.
No, OpeBTS does the GSM related DSP. You get a stream of I/Q samples from the USRP, which is more or less just the digitalization of the baseband. OpenBTS carves the time slots and "frames" out of this, does the GMSK de-modulation and similar stuff.
Note that the lower layers of GSM is very different from e.g. ethernet. Once you get past all the very gory stuff up to layer 2, the concepts are pretty much the same though.
I bought a 40 watt laser cutter/engraver from China via ebay. It cost a little less than $1800. It cuts wood and some thin plastics (acrylic) like this quite well.
Unfortunately, its quality was so terrible, it was little more than a box of parts. I had to build a new stepper driver and run it from MACH3 to get any results out of it. I also had to replace some "greased rail" style bearings with linear ball bearings to get decent accuracy.
The one they've got at MIT probably says "Epilog" on the side and costs somewhere between your car and your house.
Edit: I generally cut "luan" plywood 1/8" or thinner. It seems like about the thickest I can handle. 1/16" veneer gives me the best results.
Otherwise, you're talking $5k and up. However these guys are cheap and fast if you want to farm it out: http://www.pololu.com/catalog/product/749 (I don't work for them, and I'm not an affiliate, just a happy customer)
With all these open cell phone stacks: what do people do about IMEI? Isn't modifying IMEIs illegal in many countries? Or is the IMEI already programmed as part of some module from the factory and thus there's no need to change it?
EDIT: Whoops. I did mean IMEI and not ESN. I've edited this post.
On GSM phones, ESNs don't apply. IMEIs are the equivalent, however. In that case one of the value-adds of an integrated module is that it comes with an IMEI. If you're going into large scale production you can pay CTIA for your own block of IMEIs and reprogram your modules, but typically that's not worth it. However if memory serves (it's been about 5 years) they force you into doing this if you get above a certain production volume, otherwise it becomes difficult tor track which chunk of the traffic is yours, and whether or not you're shipping a ton of devices which haven't passed carrier certification, etc.
I'd imagine it works similarly with ESNs, but I have no experience there.
