Project Logs

Collapse

• 3D design files now available!

  Arya • 12/30/2018 at 00:10 • 7 comments

  Hi! So, about the ZeroPhone cases.

  This is one of the most popular questions, on par with the "3G connectivity", "flat battery" and "touchscreen" ones. I'm not the kind of person that'd be good at 3D design, but, thankfully, plenty of people in this community are. During these 2 years, I had a task of making the 3D model of ZeroPhone PCBs - so that people could make a case around it. I kept putting it off, and when I did have time to work on it, it wasn't successful - one of the most important things delaying me was waiting for KiCad 5, with proper STEP support (since VRML support in CAD packages universally sucks, as I've come to understand).

  Finally, we have a 3D model of the ZeroPhone, specifically, the Delta revision:
  

  It's taken a lot of work - thankfully, early in the project's beginning phase, @Dillon has helped with a lot of 3D models, designing some from scratch and sourcing others from open sources, so I'm immensely thankful for that. Current 3D model also has a lot of Grabcad material - distribution rights of which is questionable, I admit, so here's a list of all the stuff we need to replace. You can download the STEP here, and the STL here.
  

  Meanwhile. if you want some kind of reference design, here's a downloadable case design for ZeroPhone Gamma by @Ninjalicious  - albeit bulky, it's a viable way to make a case that actually works and holds up, one that's also snap-fit but provides all the vital openings for ZeroPhone hardware. Personally, I'm interested in some kind of lasercut design, but not for the practicality of it - I just like lasercut things =) Before the crowdfunding, if nobody steps up and designs an open-source case, I'll design one myself - to make sure we have something to offer during the crowdfunding.

  Also, I've had multiple suggestions from people, about making a ZP version in a case for a bulky phone, like the Motorola DynaTAC or this one. I can't say I'd be interested in such a case, but if I were to add, say, a FreeCalypso modem board (a 90x50mm PCB), this is exactly what I'd be looking for! With all the ways that you can expand on your ZeroPhone, I'm sure there's a lot of interesting stuff you could ram into such a phone - i.e. an expanded battery pack or a bigger screen, or maybe a Geiger counter and a high-power WiFi antenna... Why not all of that? =D

  ---

  Any information that's provided in this article may and will become outdated. Refer to the ZeroPhone Wiki page on 3D designs for the most up-to-date information.

• Why is self-assembly important, and why use Chinese breakouts?

  Arya • 12/05/2018 at 16:26 • 1 comment

  I've been asked these questions a lot. Mostly by people who were wondering why I need to battle with and work around problems of Chinese breakouts instead of laying out all the bits and pieces on the breakout board, and why I just wouldn't put the 2G modem/charger/DC-DC on the back board, with all the benefits it would bring. There are multiple facets to these two questions - they're closely related, and I'll be answering both of them at the same time.
  

  Typical starting point for self-assembly on more complicated OSHW projects

  First and foremost, what does self-assembly-capability even mean for ZeroPhone? At the moment, you can assemble your own ZeroPhone independently - without any help from me, without buying parts from me or even contacting me in any way. I do provide advice in case something's unclear or there's a problem, I do sell parts, and I do link people that would like to sell some parts (i.e. PCBs) with people that would like to buy parts - but it's all optional, I publish info on assembly, there's more and more tutorials, guidelines, and videos as time goes on. This isn't really something that a lot of projects do, it requires additional effort and insight, but it's doable.
  

  Read more »

• Delta-B released!

  Arya • 10/26/2018 at 23:59 • 0 comments

  Hi! Here's a long overdue worklog about a new revision that was released two months ago =D It's called Delta-B, the only changes from Delta are bugfixes; this time that's actually true - not like Gamma=>Delta which was planned to be like a bugfix-only revision, but had to get lots of additions.

  Read more »

• New app - avrdude

  Arya • 07/01/2018 at 22:20 • 0 comments

  This month, I've been working on an avrdude app - an app that uses avrdude to program AVR microcontrollers. It's now finished, with 500 LOC in the app itself and 800 more in the associated libraries. You might be surprised - why this and not something else, like a messenger app? Here are the reasons:

  • At the time, I had a small gig that involved programming 50 ATMega-based boards. So, after working with avrdude for quite a while, I was quite sick of it and wanted to automate it away - and also wanted to make sure there's a straightforward way to burn popular bootloaders to ATMega-based boards, which is a big part of this app. Now, I don't need to be summoned anywhere to program a new batch of boards - I can just give that person a ZPUI-enabled device with a user-friendly interface.
  • ZPUI needed a helper class to run long-term processes and parse their output - which is something that avrdude app would need, so after I wrote it, it only made sense to write an app around it. Such a class will be necessary for anybody who would want to write a wrapper to run any command-line tool and see what it outputs in real-time - be it ffmpeg or mjpg-streamer (which I plan to add for single-click video streaming), an interactive CLI script that needs your password, another microcontroller flasher or just a long-winded script that you want to monitor, there's now a way to wrap it in a developer-friendly object you can use to get output, send output and terminate the process at a whim (surprisingly, something that I still haven't found a proper Python library for).
  • I wanted to understand whether there's something that ZPUI lacks - it's something you can only see while you're programming a large app like this, and given that I'm the only person working on ZPUI and controlling its direction, it's crucial for me to check every once in a while if there's something that could be added to ZPUI. As a result of this work, I've added a lot of new functions, and more different ways to use the existing ones.
  • Also, I wanted to test out the recent ZPUI additions - like context switching, canvas system and class-based apps, and write a large app that uses all these things in a way that others can then refer to. While I was writing this app, I uncovered plenty of bugs and inconsistencies, which were promptly fixed.
  • Last but not least, writing large apps gives me the experience I can use to advise others on writing large apps - for now, nobody but me has this kind of experience, which is necessary to help people writing large apps that actually work.

  The end result is an Atmel MCU programming app that can backup and restore firmware from/to the MCU, flash arbitrary .hex files and bootloaders. For now, I've only tested it with usbasp programmers, but linux SPI device and other programmer support will be coming soon. I've used it a lot already, and it's even more useful given that I'm now working on several AVR-powered ZeroPhone mod boards (so, a simple way for users to update the mod board firmware is needed). It also has pinout information and the most crucial settings available, as well as some user-friendliness related features. In addition to that, there's a lot of bugfixes, improvements, new ideas for improving ZPUI and insights into problems that ZPUI has.
  

  One large problem that I now understand ZPUI has - lack of some kind of markup system for UI design. Essentially, when you're trying to draw your own UI, you need to calculate position of each element on the screen, requiring plenty of math (and extra variables) if you don't want parts of your UI to overlap/disappear. When it comes to text, the situation is even worse - as of now, it's pretty much impossible to properly word-wrap arbitrary text on a screen, for example. What do we do about it? I have no idea yet, and that's something I'll need to address sooner or later, unless I want ZeroPhone to be infamous for ugly apps... or not scaling further than the small display...

  Read more »

• Delta boards released!

  Arya • 05/24/2018 at 00:40 • 2 comments

  The new revision, ZeroPhone Delta, is out. I've been using a Gamma ZeroPhone for quite some time now, and it needs some bugfixes. Specifically, I:
  

  • Fixed a mechanical weak spot where a row on the keypad would break due to lack of structural support
  • Fixed tantalum capacitor footprints - now they're more solderable
  • Fxed the problem where traces on the 18650 board would get exposed to the back board (and short things together) due to soldermask scraping off the back board when scratched by the back board through-hole pins
  • Flipped the 3G modem upside down, making the routing significantly easier
  • Reorganized the SPI (side) expansion header footprint, changing it to use 12-pin headers (easier to source)
  • Reorganized the I2C expansion header to be compatible with the Raspberry Pi I2C pinout, allowing to connect existing I2C RPi expansion boards to ZeroPhone
  • Reorganized the IR (top) expansion header - now it's safe to plug expansion boards in reverse
  • Audio buffer, vibromotor and keypad backlight circuits are now powered from VSYS
  • Flipped the DC-DC power FET so it's no longer necessary to solder it flipped
  • Flipped the charger board - now it's easier to solder it, as well as swap and test
  • Made the Pi Zero pads on the back board oval - making them stronger (for rework purposes)
  • Changed the 4-pin GSM audio header into a 6-pin one - for easier sourcing
  • Improved the microphone footprint on the front board
  • Made fiducials smaller - mostly I needed more space for routing
  • Improved the switchable display header - the jumper pads are now smaller, and through-hole part of it is covered by soldermask on the front of the board (to avoid displays shorting to it)
  • Made the surface-mount crystal resonator pads on the front board larger, in attempt to make the resonator hand-solderable
  • Added traces to the MCP23017 footprint in an attempt to make it more reworkable

  Here's what I added:

  • Inductors in series with GSM microphone traces - for noise filtering
  • Assembly instructions/guidelines on front, back and keypad boards
  • Usage instructions on the 18650 board
  • Expansion header pinouts on the back board
  • A comparator - detecting charger&USB undervoltage and charger board overheating
  • A circuit that'd allow sensing whether the "power switch override" button is pressed while still eping the phone switched on
  • An UART buffer - not connecting the GSM UART to the Pi UART until a GPIO is asserted
  • UART testpoints near the charger board outline - to allow for a charging+UART board to be made
  • Serial number fields on front, back and keypad boards
  • An audio amplifier for the GSM speaker (unfortunately, it's a TI part - I'll be looking for a substitute)
  • An I2C EEPROM to GPIO0 and GPIO1 to the back board - to make the back board work as a Pi HAT in software
  • Better power filtering for the GSM modem power
  • A "connect 5V DC-DC to the charger input when the DC-DC is powered off" circuit
  • 3.5mm jack audio filtering to remove GSM noise
  • ATMega UART header reverse polarity protection
  • A fuse to the 18650 board between two batteries, to avoid problems when people insert batteries in reverse, or batteries with different levels of charge
  • Finally designed the first solution to attach the GSM speaker

  I also removed a lot of things that didn't prove themselves useful:

  • The RTC footprint - proved to be unnecessary and incomplete, and was taking a lot of PCB real estate
  • The GND-BATT- jumper - wasn't useful
  • The capacitor footprint in parallel with BATT+ and BATT- - wasn't useful
  • The MPU9050-compatible footprint - wasn't useful enough compared to the PCB real estate
  • The second USB socket (facing the board center) - wasn't useful
  • The RST and TV-OUT pad connections - weren't useful (though having a way to bring them back later would be cool, maybe add a pad for a surface-mount pin header?)

  OSHPark links: 18650 board, back board, front board, keypad board and speaker adapter
  

  ---

  Some of these points (like silkscreen additions) could be explained further, but I'll show them off once I receive the...

  Read more »

• Some ZeroPhone problems I'll be fixing

  Arya • 02/15/2018 at 09:26 • 7 comments

  Even though I've put a lot of work optimising ZeroPhone for everyday usage, self-assembly and manufacturing, there still are things we can do better in the next revision. Let's go through them, so that you can see the final changes I need to make to the boards, and things I need to figure out before the crowdfunding!

  This list is a result of me carrying a ZeroPhone with me through this year - and, therefore, fixing these problems will make sure your ZeroPhone lives as long as possible and is not merely some kind of gimmick that dies after a couple of months. Most of these problems are either fixable or have workarounds - if they didn't, I wouldn't have had been able to assemble the Gamma PCBs. However, they will be problematic for new people, so I have to make sure to eliminate as much of those problems as possible for the next version - to properly achieve the ZeroPhone "self-assembly" goal, making the assembly "as easy as possible" and not just "possible".
  

  Charging and protection boards

  
  We use popular modules from China for the ZeroPhone battery charging and protection. I had problems with the way those modules had to be soldered on the back board - it wasn't straightforward, and it wasn't easy to get done. So, I've flipped the footprint - now it's compatible with more module types, and it's much easier to solder the modules on - the board layout also became much more straightforward, since power traces used to be crossed and now they aren't! The component side of the modules is now exposed to the outside of the phone, though - I'll have to make sure this doesn't cause problems, such as short-circuits (possibly, release a 3D-printable cover).

  In addition, there were stability problems with a new version of these modules. Beta boards were using an earlier version:
  
  

  
  For Gamma boards, however, I used slightly different modules, a newer version  - I ordered them by mistake, so I quickly changed the footprint to fit the new modules in order to avoid ordering the older ones. 

  That turned out to be a bad idea - the newer modules seem to not function as well as the previous, some of them randomly fail (luckily, they fail safe). It happened to some of my ZeroPhones, and it also happened to some of the ZeroPhones that I sent out (which resulted in the person having to send it back, for me to repair, and that's something I'd really like to avoid). That's not acceptable - if the module is broken, ZeroPhone cannot operate from the battery at all - or it switches off randomly, which is even more annoying. Fortunately, the new, flipped footprint allows for all kinds of modules, so it should be easier to find a suitable board now!

  During the manufacturing, we'll need to find a way to either find a reliable source for these modules, or to manufacture our own (I've already reverse-engineered the schematics and the PCB, thankfully, and I'm asking for manufacturing quotes) - as a backup plan in case the commercial modules are no longer suitable for us. I've also tried understanding the problem by comparing "old" and "new" modules - I've checked the schematic and it's the same (the boards are slightly different, but the changes are minimal), so my guess is that the "new" modules are using cheaper components, which causes the failures. But, just in case, I'm going to see if there's a way for us to source these boards reliably.

  Reworkability

  
  It turned out that current ZeroPhone PCBs might have some problems while doing repairs - traces breaking, pads being lifted etc. Generally, it will only happen to low-quality PCBs - but it's hard to make sure the PCBs you're ordering are of sufficiently high quality (and if you're ordering from a place like DirtyPCBs, it's likely your PCBs won't be good enough to survive overheating). This is bad, since it makes ZeroPhone less repairable - in the end, I have two back boards and one front board that are unusable because too many pads got lifted, and I also have some more that need...

  Read more »

• ZeroPhone block diagram

  Arya • 12/25/2017 at 11:17 • 2 comments

  Merry Christmas everybody! I'm going through the ZeroPhone project files, and here's something that I haven't yet posted - by @Morning.Star:

• Writing a 2048 game for a ZeroPhone

  Arya • 12/10/2017 at 04:21 • 1 comment

  Today, I was watching my wife play 2048, and I remembered about all the fun I had with this game myself, back when it was popular. While I don't recall ever getting past 512, I did spend a lot of time and I liked it. So, ZeroPhone can fit 8 lines of text on the screen, and 2048 needs a 4x4 playing field - seems like a perfect match!

  I found some Python code on GitHub that seems to be a great fit - it's cleanly split into logic and GUI parts, and logic does not depend on the GUI in any way, so can be re-used easily. Now that's a great design, if you ask me =) Reading further into it, it seems to be somebody's programming assignment, and I have to say that it was very helpful of that person to put it on GitHub!
  

  So, let's reuse the logic part, and build our own UI for the game!

  Read more »

• ZeroPhone uses: streaming audio from desktop to headphones

  Arya • 11/13/2017 at 06:43 • 0 comments

  Do you ever feel tethered to your computer because you're wearing headphones, and you can't go away from it because you can't use your speakers for whatever reason? This is for you.

  I often found myself in this situation. Sometimes I'm listening to podcasts, and I want to get up from my desk and grab something from other room, but the speakers aren't loud enough. Sometimes people around are sleeping and I don't want to wake them up, but I also can't carry my laptop with me just because I like the track I just found on YouTube. 

  One of ZeroPhone plans is enabling hands-free applications, using audio for things like notifications (of course, only the most important ones, and the ones you want to hear.) Naturally, I'll be using it a lot  - I'm the "headphones" kind of person, and I know there are plenty of ZeroPhone notifications I'll want to hear about immediately when they happen. Now, what if I want to listen to a podcast, should I unplug headphones from my ZeroPhone and not hear the notifications? The most obvious idea is using the ZeroPhone as an audio receiver, and stream audio from my laptop to ZeroPhone, so that notifications could be overlayed, and I wouldn't find myself re-plugging the headphones all the time.

  So, the setup is like this: I want to stream all audio from my Windows laptop to my ZeroPhone, which sits in my pocket, receives the audio stream and plays it back to my headphones. If my laptop ran Linux, I could just use pulseaudio network streaming capabilities and be done with it. As it's Windows, though, I needed to find something that would work on Windows and would be more user-friendly than using a long command-line copy-pasted from Stackoverflow.

  Read more »

• An in-depth explanation of a simple GPIO app

  Arya • 11/08/2017 at 04:09 • 0 comments

  For Hackaday Prize video, I made some simple ZPUI apps (some of them were mockups, though). One of them was reading an external flame sensor and displaying pictures on the screen depending on whether the sensor detected flame or not. I had to do this in a rush, and I ended up adding some basic, but very useful, functions to ZPUI (though I did have to clean them up quite a bit before I could merge them into official ZPUI version =) ). 

  What's the algorithm of this app?
  

  Set up the GPIO
  In a loop, read from the GPIO pin
  If pin has logic low on it:
      display picture of fire
  Else:
      display picture of fire crossed out

  The app is, therefore, very short. So, let's go through it thoroughly, explaining it in as much detail as possible!
  

  Read more »

View all 50 project logs