Is it difficult to make a cell phone ( 4G ) ? - Page 1
Forum section: electronics / projects

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 02:43:20 pm
content: Hi, i would like to know how simple or difficult it is to make a cell phone for 4G network ?thanks

author: Siwastaja
author_rank: Super Contributor
timestamp: March 11, 2021, 02:55:22 pm
content: All the magic is inside chips, in silicon design, both analog RF and digital logic.So if you can get the chips, and if you can get the documentation - neither of which you as mere mortal can't - the rest isn't too difficult.The chip design incorporates decades of wisdom from the brightest minds of this planet, however. No single person is able to recreate that.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 02:57:26 pm
content: So you cant order those chips from mouser ?Ohh, shocking.

author: LaserSteve
author_rank: Super Contributor
timestamp: March 11, 2021, 03:42:47 pm
content: You can order a OEM module that takes a SIM card. That is about it.Steve

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 03:54:02 pm
content: There are many brands that make cell phones,how do they all get the chips and info ?

author: Gyro
author_rank: Super Contributor
timestamp: March 11, 2021, 04:08:57 pm
content: Because they haveextremelyclose relationships with their suppliers when it comes to specifying chip functionality and buy vast quantities. Obviously!

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 04:11:44 pm
content: I mean how do you start as new brand then ?Bribe them ?

author: Ice-Tea
author_rank: Super Contributor
timestamp: March 11, 2021, 04:14:14 pm
content: No, but you will need a convincing story and promise loads of volume.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 04:17:36 pm
content: If you have no clue if it works for you, just buy in quantity, sounds risky.

author: Ice-Tea
author_rank: Super Contributor
timestamp: March 11, 2021, 04:20:57 pm
content: I didn't say "buy loads" but "promise loads of volume". Contacting Broadcom asking for full disclosure for a 10k production run of "Ultra High Audio Grade cell phones" won't even cause a blip on their radar.Contacting them with a convincing bussiness plan for 1M+ units a year will probably see you through the door.

author: Gyro
author_rank: Super Contributor
timestamp: March 11, 2021, 04:23:21 pm
content: Quote from: Jan Audio on March 11, 2021, 04:17:36 pmIf you have no clue whether it works for you, then trust me, you don't. It requires very significant investment development facilities and design staff for a start.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 04:23:51 pm
content: Maybe aliexpress have them also.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: March 11, 2021, 04:24:13 pm
content: Quote from: Jan Audio on March 11, 2021, 04:17:36 pmIf you have no clue then perhaps the cell phone industry isn't the right one for you.

author: Gyro
author_rank: Super Contributor
timestamp: March 11, 2021, 04:25:02 pm
content: @Jan Audio. You're just trolling.

author: Ice-Tea
author_rank: Super Contributor
timestamp: March 11, 2021, 04:27:11 pm
content: Quote from: Jan Audio on March 11, 2021, 04:23:51 pmChips? Probably. Working chips? Perhaps.Documentation? No.

author: tszaboo
author_rank: Super Contributor
timestamp: March 11, 2021, 04:27:35 pm
content: Quote from: Jan Audio on March 11, 2021, 04:11:44 pmYou can't buy chips. You would need to prove them, that you can pass GSMA FCC CE and other certifications before they would even consider selling anything to you. All this is like 100KEUR budget, if everything passes first try.Buy a module. Most modules have either direct audio in/out or I2S. Putting together a phone to call is not that hard for an experienced engineer. For example page 157 below shows you how to make a phone.https://www.u-blox.com/en/docs/UBX-13004618But then you have a board that does nothing. Then you need to start antenna matching from almost DC to daylight. That can take a few days getting it right.And then writing software. Which can be ridiculously complicated. The issue is not making a call, that is a few AT commands. Where the complexity comes from is network providers doing all kinds of crazy stuff. They do this for political reasons, backwards compatibility, network limitations, and so on. You want to roam in France, and you suddenly cannot connect to your preferred network. And the modem only tells you that you have some sort of unspecified error. You search the error, and there is like 1 forum post from 2011 from a guy who tried to do the same as you. Nothing is documented about these things. And this is just the tip of the iceberg.

author: Kosmic
author_rank: Super Contributor
timestamp: March 11, 2021, 04:40:45 pm
content: The best way these days to play with the cell networks is with SDR. You don't need the cellphone chip. Just do everything in software!With something like that for example:https://github.com/srsLTE/srsLTE

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 04:51:02 pm
content: Ok, it is not the 4G frequency i see, so it wont work i assume.btw : i have no idea what it is.

author: jonpaul
author_rank: Super Contributor
timestamp: March 11, 2021, 04:54:24 pm
content: Acess to Cellular chipsets is highly restricted due to security considerations.You need to pay patent license fees and negotiate an agreement.Finally FCC clearance is required with testing.I would think the minimum to start is ~ 10-100M$.Bon Chance,Jon

author: Kosmic
author_rank: Super Contributor
timestamp: March 11, 2021, 04:55:15 pm
content: Quote from: Jan Audio on March 11, 2021, 04:51:02 pm4G is pretty vague. You need to decide which protocol/tech you want to support.LTE ==https://en.wikipedia.org/wiki/LTE_(telecommunication)#:~:text=In%20telecommunications%2C%20Long%2DTerm%20Evolution,together%20with%20core%20network%20improvements.Frequency used and protocol are 2 different things. You could have a 5G link on 900Mhz if you wanted. Just going to be a bit slower.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 04:59:35 pm
content: I dont know if the callcenter of my provider knows what 4G protocol they are using.I also cant find it online.Ok not so simple.

author: Kosmic
author_rank: Super Contributor
timestamp: March 11, 2021, 05:01:31 pm
content: Quote from: Jan Audio on March 11, 2021, 04:59:35 pmNormally you can find that information online. The protocols and frequency bands they are using. It's pretty standard stuff.Your typical cellphone would support multiple frequencies and protocols though. You can find that in the specs of the phone.

author: Monkeh
author_rank: Super Contributor
timestamp: March 11, 2021, 05:02:42 pm
content: Quote from: Jan Audio on March 11, 2021, 02:43:20 pmSo far beyond your skillset it's not even remotely worth contemplating.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 11, 2021, 05:03:22 pm
content: O no not him again.Quote from: jonpaul on March 11, 2021, 04:54:24 pmOne thing i dont understand : if you use those parts, why is the testing still needed ?, they already tested those parts.

author: Monkeh
author_rank: Super Contributor
timestamp: March 11, 2021, 05:05:02 pm
content: Quote from: Jan Audio on March 11, 2021, 05:03:22 pmThe individual components are not representative of the total design. There are many software settings, many possible mistakes in amplifier configuration, antenna design..

author: ejeffrey
author_rank: Super Contributor
timestamp: March 11, 2021, 05:13:07 pm
content: If you want to make a candy bar sized device with a high performance SoC, multiple state of the art radios, full size screen, and all day battery life that's impossible. You won't get the chips, the documentation, or the licenses. Even if you did the development effort, production NRE, and FCC approval are well beyond a hobby project. If you actually have the team and the budget to actually do this in large volume it won't be hard to get contacts from the chip manufacturers.If you just want to make a device that speaks to the cell network, that is possible. There are LTE chips and modules targeting the IoT related fields. You may still need an NDA and seem legit to get the documentation, but its a whole different ballgame than state of the art cell phone SoCs. It won't have the performance, integration, cost, or efficiency of what is in even a low end phone, but it can get your device talking to the network.The best bet is to get a complete module. In particular that will take care of a lot of the FCC licensing concerns since it will contain the whole radio stack (baseband processor, radio, filters, amplifiers, etc) and have its configuration fixed for a specific market. Here are some hits you could have found with a quick google search:https://www.u-blox.com/en/cellular-moduleshttps://www.lairdconnect.com/wireless-modules/cellular-solutionshttps://store.particle.io/products/e-series-lte-modulehttps://www.mouser.com/ProductDetail/Quectel/EC21JFA-512-STDNone of those are going to make you a modern cell phone, but if you are actually serious about making a project that works on the LTE network, there are a lot of options.

author: Bud
author_rank: Super Contributor
timestamp: March 11, 2021, 05:35:32 pm
content: @OPWhy ?

author: DrG
author_rank: Super Contributor
timestamp: March 11, 2021, 05:42:15 pm
content: Kit:https://www.makershed.com/products/ringo-diy-mobilephoneAlready built:https://www.target.com/p/skip-hop-zoo-unicorn-baby-cell-phone-toy/-/A-76474741

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 11, 2021, 07:01:27 pm
content: If you want to design a cell phone as an individual or a very small company, your best bet would be to use a ready-to-use LTE module.For instance:https://www.u-blox.com/en/product/toby-l2-series?utm_source=en%2Fwireless-modules%2Flte%2Ftoby-l2-lte-module-series.htmlNote that for personal use, that should be OK... maybe... but if you're planning on selling products based on this, this is another story. Complying with current regulations is a pain, and using such a module would not exempt you from doing all the testing and paperwork on your final product.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 12, 2021, 04:49:12 pm
content: Quote from: ejeffrey on March 11, 2021, 05:13:07 pmI want a phone that you can call with, and text, nothing else, i dont mind it being big as a 80s cell phone, i would like it with handle-bar and antenna i dont mind.no facebookno googlethe list goes on.utopia.

author: Monkeh
author_rank: Super Contributor
timestamp: March 12, 2021, 05:04:53 pm
content: Quote from: Jan Audio on March 12, 2021, 04:49:12 pmhttps://www.nokia.com/phones/en_gb/nokia-225-4gDone.

author: YurkshireLad
author_rank: Frequent Contributor
timestamp: March 12, 2021, 05:10:48 pm
content: Quote from: Monkeh on March 12, 2021, 05:04:53 pmFrom the website:"You’ve even got essentials like Facebook..."

author: Monkeh
author_rank: Super Contributor
timestamp: March 12, 2021, 05:13:38 pm
content: Quote from: YurkshireLad on March 12, 2021, 05:10:48 pmAnd it's totally impractical and you don't have to use it. Much like on any other phone, actually. There are even dumber phones, but he wanted 4G, presumably out of awareness that awful legacy standards have to die sooner or later.

author: tszaboo
author_rank: Super Contributor
timestamp: March 12, 2021, 09:35:01 pm
content: Quote from: Monkeh on March 12, 2021, 05:13:38 pmGetting replaced by equally awful standards.I still dont get it, how could they define the LTE CAT M frequency bands like a swiss cheese from 800 MHz to 3.something GHz.

author: amyk
author_rank: Super Contributor
timestamp: March 13, 2021, 12:27:48 am
content: This question goes into the "if you have to ask..." territory.That said, the protocol specs are availableat the 3GPP site; what's not so easy is understanding them.You can also find a lot of leaked stuff including source code if you search the right way, mostly from Mediatek and shared amongst various Chinese forums.

author: bson
author_rank: Unknown
timestamp: March 13, 2021, 01:53:57 am
content: The Pine64 uses a Quectel EG-25G module. I'm pretty sure the AAEON-UP is the same:https://www.mouser.com/ProductDetail/AAEON-UP/RE-UPLTEG25GSIM/?qs=Zz7%252BYVVL6bFvuIPew%252BvNpw%3D%3D

author: ejeffrey
author_rank: Super Contributor
timestamp: March 13, 2021, 02:32:47 am
content: Quote from: Jan Audio on March 12, 2021, 04:49:12 pmTake it one step further:https://www.thenophone.com/Or you could get a cheap phone and not use the features you don't want.

author: DrG
author_rank: Super Contributor
timestamp: March 13, 2021, 03:38:40 am
content: If one did want to know what goes into making a phone, I would still consider the kit posted in #27.You can get the schematics and the codehttps://github.com/CircuitMess/CircuitMess-RingoIt's been around for a while, can have 4G (SIM7600) chipset, ESP32, display and so on. If one really wondered how difficult it is to make a cell phone, this would be a good place to start - or to put you off the idea

author: Someone
author_rank: Super Contributor
timestamp: March 13, 2021, 03:57:28 am
content: Quote from: ejeffrey on March 13, 2021, 02:32:47 amGeneral rule: if there is a mass market consumer product that can do the job, you are unlikely to find any cheaper way of doing it, and you certainly won't be able to build or make a cheaper something that can do the job.Dumb phones exist, they are marketed to specific users and are undesirable for the salespeople/networks as they don't drive recurring income. Australian examples below.

author: james_s
author_rank: Super Contributor
timestamp: March 13, 2021, 05:29:49 am
content: Quote from: Jan Audio on March 12, 2021, 04:49:12 pmYou know, you don't have to use features you don't want, even on a smartphone you don't have to install any apps and you can delete most of the stuff that comes on it.You can also still buy basic phones, they're called "feature phones", they're getting harder to find because almost nobody wants them anymore but they are still available.If you are seriously considering building one, I would suggest getting evaluated by a professional psychiatrist. Aren't you the guy who was complaining that hobbyists can't even work with surface mount components? Mobile phone chipsets are some of the tiniest most dense components available.

author: gnuarm
author_rank: Super Contributor
timestamp: March 13, 2021, 07:16:04 am
content: Quote from: Gyro on March 11, 2021, 04:25:02 pmI think everyone in this thread is Trolling including you and I.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2021, 12:43:11 pm
content: Yes the network will block my working nokia dumb phone at 1 juni this year.Those nokia telephones available now all have a camera, google assistent, facebook, all pre-installed.I dont want those thing making use of my phone behind my back.Did you know a regular used smartphone connects to 10.000 IP adresses within 1 hour ?First of all i pay each month almost 7 euro, suppose that google or facebook becomes alive and uses the internet, i will be poor, they dont give a warning message if you need to pay above your normal payment,they only send a message if i am to late with paying.I dont believe you can remove facebook and google assistent from any phone, if it is possible show me please.I always say : a smart-phone is for dumb-people.Really who is using your phone the most ?, they want you to wear one at all times, because of GPS and the ban of cash money.Some "....." people pay 200 per month, i laugh very hard.Quote from: james_s on March 13, 2021, 05:29:49 amI did not say i wanto build one (yet)I just like to know if it can be done, i need a extra good reason to start with SMD.

author: Gyro
author_rank: Super Contributor
timestamp: March 13, 2021, 01:41:29 pm
content: Quote from: gnuarm on March 13, 2021, 07:16:04 amYes, I think we would have all benefited from greater clarity in the OP. We would all have got off to a much better start then regarding expectations(difficult though when he talks about finding chips on aliexpress).

author: cgroen
author_rank: Unknown
timestamp: March 13, 2021, 02:24:33 pm
content: Quote from: Jan Audio on March 13, 2021, 12:43:11 pm

author: Monkeh
author_rank: Super Contributor
timestamp: March 13, 2021, 03:31:04 pm
content: Quote from: Jan Audio on March 13, 2021, 12:43:11 pmGood news: They don't.QuoteWell, your provider is crap. Also, suppose your mattress becomes sentient and decides to eat you one night.QuoteWell, there's no Facebook on my phone. No, I won't show you how to use Google.QuoteThank you for insulting those of us who make use of tools instead of crying about them.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2021, 03:42:38 pm
content: Quote from: Monkeh on March 13, 2021, 03:31:04 pmDid you not know a regular used smartphone connects to 10.000 unique IP adresses within 1 hour ?Only you dont see, how do you know then ?, how can you be sure the telephone is not connecting to anything ?If a telephone can only call then i am sure it wont connect to anything.

author: DrG
author_rank: Super Contributor
timestamp: March 13, 2021, 04:14:23 pm
content: Quote from: Jan Audio on March 13, 2021, 03:42:38 pmHow do you know it isn't 21,345 connections within an hour? If I have a slow phone will it connect to 10,000 addresses within 2 hours? If I get 5G can I connect to 20,000 within an hour?If I store the phone in a lead box, cleverly disguised as a book, can I stop all those connections and farcebook using my camera when I turn my back?https://www.amazon.com/MONOJOY-Faraday-Keyless-Blocking-Shielding/dp/B07WG6F8DH/ref=sr_1_2?crid=3EJY4JWI80XRQ&dchild=1&keywords=lead+box+for+cell+phone&qid=1615651551&sprefix=lead+box%2Caps%2C150&sr=8-2Does this have anything to do with NASA?Yes, I am making light of your post and the thread because you have ignored all attempts at serious responses and it seems like you are either trolling or just are not interested in learning at all.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2021, 04:20:21 pm
content: I still wanna call, else i would buy the nophone.

author: Monkeh
author_rank: Super Contributor
timestamp: March 13, 2021, 04:28:14 pm
content: Quote from: Jan Audio on March 13, 2021, 03:42:38 pmWell, unlike you, I do see, and my phone in the last 10 minutes has connected to exactly 9 IPs, two of which are within my network(s). It's got a lot of work to do to make it to 10,000.

author: MK14
author_rank: Super Contributor
timestamp: March 13, 2021, 04:31:03 pm
content: Quote from: DrG on March 13, 2021, 04:14:23 pmNo, you are getting suckered into the wrong/silly answer.Obviously, it is actually the NSA, not NASA.https://en.wikipedia.org/wiki/National_Security_AgencyOn a more serious note, I'd suggest going to 1G, not 4G. Since 4G needs surface mount (ONLY) components, and too many unobtainium 320K 1% resistors.Source:https://www.eevblog.com/forum/chat/what-happend-to-320k-resistors/msg3472288/#msg3472288

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 13, 2021, 04:48:53 pm
content: Look i mean it all serious.

author: MK14
author_rank: Super Contributor
timestamp: March 13, 2021, 04:55:04 pm
content: Quote from: Jan Audio on March 13, 2021, 04:48:53 pmThen the answer isYES, itISdifficult to make a (4G) cell phone. If you can't do surface mount components and/or can't even sort out buying a simple resistor, without accepting even the slightest/tiniest of compromises.

author: Monkeh
author_rank: Super Contributor
timestamp: March 13, 2021, 05:09:19 pm
content: Nearly an hour now, 416 IPs and a total of 1.4MiB. Damn, I'm going to go bankrupt.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: March 13, 2021, 05:33:14 pm
content: Perhaps OP should spend time reading articles like this:https://www.techbout.com/stop-apps-using-cellular-data-android-phone-13411/

author: ejeffrey
author_rank: Super Contributor
timestamp: March 13, 2021, 06:03:50 pm
content: You can also turn mobile data off on most phones. I'm not sure if that impacts VoLTE because honestly I don't care, but it is a think you can do that will prevent it from contacting "10000 IP addresses per hour"

author: james_s
author_rank: Super Contributor
timestamp: March 13, 2021, 06:51:57 pm
content: Quote from: MK14 on March 13, 2021, 04:55:04 pmThat's an understatement. It's difficult enough that I'm not aware of any hobbyist who has ever done it, and I've seen some really impressive hobby projects. It would be forging new ground, accomplishing something so complex that even well funded startup companies with teams of engineers have failed to complete a working prototype.A much easier project would be take a basic off the shelf phone and write custom firmware for it to remove and lock out everything you don't want. You might even find a dozen other users out there who would want to use it, but most people are going to roll their eyes and wonder why.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 13, 2021, 07:13:20 pm
content: Three transistors. No SMT. No Facebook.IP connections over the last hour: 0

author: MK14
author_rank: Super Contributor
timestamp: March 13, 2021, 07:33:14 pm
content: Quote from: Alex Eisenhut on March 13, 2021, 07:13:20 pmAmazing, what you can do with ONLY 3 transistors.Three transistor circuit, here:https://flic.kr/p/akyUSv

author: DrG
author_rank: Super Contributor
timestamp: March 13, 2021, 07:36:53 pm
content: Quote from: Alex Eisenhut on March 13, 2021, 07:13:20 pm0 transistors, No SMT, No Farcebook, No Twatter, No Giggle, built-in speaker phone, No usage limits.(you knew it was coming)

author: Monkeh
author_rank: Super Contributor
timestamp: March 13, 2021, 07:48:43 pm
content: Quote from: DrG on March 13, 2021, 07:36:53 pmBut he can't find the right string! He only uses this one string he found 15 years ago at a car boot sale!

author: tszaboo
author_rank: Super Contributor
timestamp: March 13, 2021, 10:34:16 pm
content: Quote from: MK14 on March 13, 2021, 07:33:14 pmIt has these double wiggly things in them. Two of them. With lots of frequency probably. And a wiggly bit with an arrow.Honestly, I rather have a small magic black box with lots of metal parts coming out of them, with the transistors inside, than the wiggly parts, because buying and selecting those is pain in the neck.

author: MK14
author_rank: Super Contributor
timestamp: March 13, 2021, 11:05:09 pm
content: Quote from: NANDBlog on March 13, 2021, 10:34:16 pmIt seems to be using a Quarts crystal, to very reliably/accurately set the transmission frequency, so a couple of adjustments, isn't too bad.So, a crystal oscillator, using a speaker as a microphone, and the capability to transmit, all from just 3 transistors, which also can be reconfigured to act as the receiver, on the other side/unit. Seems quite cute/simplistic/elegant.Who knows what other functionality, is contained within those magic black boxes (modern stuff). Does it/they send your private details to China/NSA/Hackers etc ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 14, 2021, 01:33:16 pm
content: Quote from: Jan Audio on March 13, 2021, 12:43:11 pmJust find a phone that supports LineageOS.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 14, 2021, 02:41:10 pm
content: Quote from: james_s on March 13, 2021, 06:51:57 pmThat would be the best if that is possible.Quote from: NiHaoMike on March 14, 2021, 01:33:16 pmSounds linuxy/open sourcery.That exists ?, nice one

author: Monkeh
author_rank: Super Contributor
timestamp: March 14, 2021, 02:42:52 pm
content: It's just Android, so it's still a smart phone for dumb people.

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 14, 2021, 02:43:34 pm
content: Quote from: james_s on March 13, 2021, 06:51:57 pmImagine the freedom the world will have if this would be a normal DIY project.Maybe someone will read this and have a nice plan.

author: Bud
author_rank: Super Contributor
timestamp: March 14, 2021, 03:03:18 pm
content: Purism Librem phoneQuote

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 14, 2021, 04:13:04 pm
content: After all those posts I'm not sure what you're really after.As some of us said, you can buy some LTE module and design a basic cell phone (but still 4G) around this, some MCU, LCD display and a few buttons. Ready-to-use LTE modules are not exactly cheap, but there's really no alternative. Designing an LTE front-end directly yourself is a dead-end unless you're very experienced and have an enormous amount of cash to waste. So all in all, with a module, for about $100 of parts, and a number of hours of software coding, you could get there. I think there are already such projects out there that you could take a look at. If all you want is make and receive calls, that's doable. Now as I said, whether you'd actually be allowed to use this, I don't really know, but if you don't intend on selling it, it's for your personal use only, and you use the LTE module as documented, with a compatible antenna and clean power supplies, that should be OK.Could be a fun project. But other than this, really I can't see why you wouldn't just buy a second-hand old mobile phone with no Android/iOS/Windows Mobile. Something just 2G for instance. I have no crystal ball of course, but I'm pretty sure those are still going to work on most networks for many years.If you want something more modern, as I think others have already suggested, just select a phone that is supported by open-source initiatives, there are quite a few!There are Android-based OSs with most nasty stuff either not included or disabled. There also are Linux-based OSs now. Those are safe bets for what seems to be what you want.So here, you have 3 options. Make your own with a ready-to-use module. Or buy an old phone and use it until no network supports it. Or buy a newer phone and install an open-source OS on it.Here a list of alternative OSs:https://itsfoss.com/open-source-alternatives-android/

author: tszaboo
author_rank: Super Contributor
timestamp: March 14, 2021, 10:29:23 pm
content: Quote from: SiliconWizard on March 14, 2021, 04:13:04 pmOr maybe we see next week a new topic."What temperature to use for silicon crucible?"Hwy guys I'm trying to make a phone, and I decided that the best way of doing it is with custom silicon.Now, I've seen the Escapist (great show) where Richard Hammond made glass in a crucible. I want to replicate this process but make 15nm transistors on it (I've hear that intel has trouble with their 7nm process, so I would only try twice as that). Also, what kind of microscopes do you use for this?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 14, 2021, 11:07:18 pm
content: Germanium has a lower melting point. Probably easier to etch too.

author: james_s
author_rank: Super Contributor
timestamp: March 15, 2021, 02:52:48 am
content: Quote from: Jan Audio on March 14, 2021, 02:43:34 pmI have no interest whatsoever in building my own mobile phone. Smartphones are cheap and reasonably reliable, I don't use a lot of apps but the apps I do use are exceptionally useful. It is my phone, my camera, my music player, my GPS navigator and the remote for my home automation. My phone is a tool and one that I rely on heavily, I don't want to tinker with it and hack, I want it to just work. I wouldn't mind having a more open phone OS as an option but it would have to be quite polished for me to bother. Looking at what is selling well it seems the vast majority of people want big flagship phones with all the bells & whistles, I struggled to find a small phone but I've been pretty happy with the one I have.

author: Mecanix
author_rank: Frequent Contributor
timestamp: March 15, 2021, 03:48:50 am
content: Good read!Time for Open Source Hardware/Software Mobility coupled with its own decentralized network me think. What's up with all the monopoly, restrictions and control? jeez... as if its all alien tech 11011001 or some intercontinental spying world annihilating device lolHappy to donate to the upcoming crowdfunded network satellite launches too... hit it.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 15, 2021, 10:45:21 am
content: Easy if you have a great engineering team, loads of cash and you can handle being sued by apple, google and other evil empires.Not for doing anything wrong of course, but just because they can (ask AMD).You might get your shoe in the door just before they cut off your head!https://shop.fairphone.com/en/?ref=headerhave been successful though, with a 70 strong team.A real phone that just did calls and text would be a great leap forwards -burning batteries to run a load of BS apps is bad for the planet and our minds.

author: Berni
author_rank: Super Contributor
timestamp: March 15, 2021, 11:45:17 am
content: You can just buy a brand new "dumb phone" that connects to modern networks such as a Nokia 3310 3G:https://www.gsmarena.com/nokia_3310_3g-8876.phpOr if you want it to be 4G there is something like this:https://www.gsmchoice.com/en/catalogue/doro/7010/There are dumb phones out there if you want one, you just have to look. They don't run any modern smartphone OS so they are not able to run any apps past the Java stuff that old phones ran, they don't have GPS, they can't open modern websites etc... One of the ways to find these phones is by looking for phones designed for elderly people, those are designed primarily for making phone calls since that's the only thing there target audience knows to do with them. You can rip out the camera if you don't want one(Those are mainly there for video calls).But even if you have a 2G GSM phone the network operator will always know your location because the cell network uses that to work correctly(Handoff between towers and compensating for radio time of flight delay).

author: 2N3055
author_rank: Super Contributor
timestamp: March 15, 2021, 12:46:16 pm
content: Quote from: Berni on March 15, 2021, 11:45:17 amSome 10 years ago, I tested triangulation from towers, and could reliably get position down to 50m EPE with averaging....It works so well, that smartphones use that to bootstrap GPS, even from coldstart of GPS, it will get position much faster ( 10 seconds ) than dedicated GPS device from coldstart.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 15, 2021, 01:13:57 pm
content: Quote from: Jan Audio on March 14, 2021, 02:41:10 pmThere's a very long list of officially supported devices and quite a few unofficial ports for other devices on XDA.https://wiki.lineageos.org/devices/

author: Jan Audio
author_rank: Frequent Contributor
timestamp: March 15, 2021, 04:46:40 pm
content: Quote from: SiliconWizard on March 14, 2021, 04:13:04 pmThey stop supporting 2G is the problem, i already have such a phone.Quote from: Mecanix on March 15, 2021, 03:48:50 amNo rules in space, the problem is to get it in space.

author: Bicurico
author_rank: Super Contributor
timestamp: March 15, 2021, 05:50:33 pm
content: @Jan Audio:1) What do you want to achieve, really? Why do you want to build a 4G cell phone from scratch? I ask, because maybe you don't really need/want to start from scratch and could use a different approach, i.e. as already mentioned, using a mobile phone module (SoC), using a cheap phone and rip off the required parts (for a one timer) or, like what they do with expensive luxury phones, getting a premium smartphone, redesign its case (i.e. in pure gold and covered in diamonds - for inspiration see here:http://www.goldvish.com/single-post/2016/04/22/guinness-world-records-most-expensive-phone-for-goldvish) and modifiying the firmware (see XDA Developers forum).2) When you ask how difficult it is to make a cell phone (4G), you need to add your starting point! How difficult it would be for Nokia, based on their 3G technology or for you based on existing chips, or based on existing chip layouts, based on existing knowledge, based on existing manufacturing processes, etc. This can be taken to the extreme: imagine you are able to carry the latest Samsung Galaxy S21 Ultra plus a network cell and all required hardware to operate it and travel back to 1960. How much time would be needed to replicate the mobile phone technology of 2021? My guess is that it would basically take more or less the same time! Why? Because the world would not be able to deliver rare earth metals, battery technology, RF knowledge, xx nanometer chip design, software technology, etc.So if you would want to start from scratch to develop a 4G cell phone, you would need to develop:- software- chips- manufacturing processes- materials engineering- etc.If you "cheat" and say you would start with FPGA and what not, you would still have to develop more than you could achieve in a lifetime. Think of compression algorithms, modulation algorithms, antenna design, etc.3) Your question does not specify how many people are to be involved! Is it just you, 10 people, 100 people or 1000 people? How "smart" and "educated" are the people on your team? Do they cover all required technological aspects?4) Your question does not specify how much money you are prepared to invest. As others mentioned, the certification and NDA's will cost you a 6 figure number alone!If you are really committed into developing your own 4G cell phone and I have no doubt that there are people smart enough to put this off, your way to go is this:1) Get yourself a propper SDR, like this:https://www.ettus.com/all-products/un210-kit/2) Learn how to program it using the SDR, FPGA, etc.3) Install GNU Radio4) Learn how to use GNU Radio, how to develop in Python and C++ for GNU Radio5) Build the required blocks (many are already available)6) Build a 4G implementation using the blocks7) Publish the results of your software defined 4G cell phone and you will be a star! I mean that seriously.Regards,VitorPS: It has already been done (partially) -https://github.com/kit-cel/gr-lte

author: robca
author_rank: Frequent Contributor
timestamp: March 15, 2021, 09:07:00 pm
content: Quote from: Jan Audio on March 13, 2021, 03:42:38 pmYou seem to be missing a pretty fundamental point: if you disable data connection on a feature phone like the ones suggested, you will get a phone that can only make audio calls and send SMSThere's no need to build your own phone if all you want is a phone that can only make phone calls, even a 4G one. Simply disable completely data connectivity, and you can be sure that none of the phone built in apps can do anything. It won't matter if the phone has Facebook built in.

author: amyk
author_rank: Super Contributor
timestamp: March 16, 2021, 01:39:32 am
content: Quote from: Bicurico on March 15, 2021, 05:50:33 pmAlsohttps://bellard.org/lte/(that guy is a real genius - has written a bunch of other amazing things, including ffmpeg, QEMU, TCC, etc.) Of course, he doesn't have to ask "is it difficult"... he just does it.

author: kutte
author_rank: Contributor
timestamp: March 16, 2021, 06:07:26 pm
content: They stop supporting 2G is the problem, i already have such a phone.No rules in space, the problem is to get it in space.@Jandid you realize that 4G -also called LTE - has been designed for data communications and not so much for telefone use. Many smartphones switch back from from 4G to 3G or 2G if you want to make a phone call or use voice over LTE (VoLTE similar to VOIP).I do'nt think, that is what you want.Kutte

author: Monkeh
author_rank: Super Contributor
timestamp: March 16, 2021, 06:09:42 pm
content: Voice is just data anyway. No reason to design a network to do anything but carry IP.

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2021, 09:59:44 pm
content: Anybody remember when they used to charge obscene amounts of money per text message? It was something like $0.25 each to send or receive. I never used them back then but I remember thinking that just a few seconds of voice must use as much data as hundreds of text messages.

author: GodIsRealUnless DefinedInt
author_rank: Contributor
timestamp: March 17, 2021, 12:34:59 am
content: Here is the $12 retail price Chinese street phone for the curious.Quadband GSM, Bluetooth, 260 MHz 32-bit cpu, 2 color oled display, 8 MiB RAM USB, microSD, Sim connectors, lipo battery. This was to see what could be done in China comparison to less than a price of a pizza in the west. Over here you would never be able to pull something like this off and you might get an 8bit arduino clone with 2K RAM for that much. I'm sure they will have other radios for more money.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 17, 2021, 01:00:44 am
content: I'd like to see this backhttps://en.wikipedia.org/wiki/Motorola_StarTAC

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 17, 2021, 01:39:38 am
content: Quote from: GodIsRealUnless DefinedInt on March 17, 2021, 12:34:59 amIn the US, there occasionally are deals on really cheap smartphones, sometimes as low as $5. I suspect the intent is to get kids using smartphones at an early age, but it turns out they also get great performance for the price for mining certain cryptocurrencies.

author: Berni
author_rank: Super Contributor
timestamp: March 17, 2021, 06:12:21 am
content: Quote from: NiHaoMike on March 17, 2021, 01:39:38 amThose are usually tied to cell carrier contracts. It is a common tactic here to sell you a phone for 1€ but you bind yourself to that carrier for 2 years or something so that they can make back the cost of the phone. It was mostly a deal to get you onto there network. Back then they ware also allowed to sim lock the phones so that the phone would only work with that carriers sim card. This later became illegal so they had to unlock your phone if you asked to.The US carriers tended to go even deeper than that and secure exclusivity deals with phone manufacturers. So some phones became only available on one carrier, so if you wanted that phone you needed to switch to them.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 18, 2021, 12:53:42 am
content: Quote from: Berni on March 17, 2021, 06:12:21 amThe ones I'm referring to do not require signing up for service to get for that price. That's what makes them particularly good for some cryptocurrency mining - relatively cheap to build a cluster of them as some did to mine Perk back in the day.

author: Gyro
author_rank: Super Contributor
timestamp: March 18, 2021, 12:23:04 pm
content: Quote from: GodIsRealUnless DefinedInt on March 17, 2021, 12:34:59 amThat reminds me, although they're usually difficult to forget! ...

author: gnuarm
author_rank: Super Contributor
timestamp: December 27, 2021, 04:44:45 pm
content: Quote from: Gyro on March 18, 2021, 12:23:04 pmWow! I thought it was funny the way they changed camera angles every time she bends over to pick up another phone. lol

author: Terry Bites
author_rank: Super Contributor
timestamp: December 27, 2021, 06:18:30 pm
content: Incestuous rather than just close!