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15in libre hardware laptop PCB progress
by Luke Kenneth Casson Leighton 16 Aug '15

16 Aug '15

ok, so i started last week on the PCBs. first thing: there's three of them. the casework, needing to have a middle strut as well as other internal supports, makes it impossible to have a single PCB, apart from anything that PCB would be just over 12in wide. also things need to be on different levels. so the PCBs are divided as follows: * PCB1 - contains the CPU card, I/O connectors, LVDS converter IC, USB Audio IC, USB Hub, EOMA68 identifier EEPROM, and some ribbon connectors * PCB2 - contains an STM32F070 and 3 FPCs: one for the touchpanel LCD (which has an SPI converter IC on it), one for the capacitive touchpanel (I2C), and one 16+8 1mm pitch connector for the keyboard. * PCB3 - contains the battery charger and power IC (an LTC4155) as well as a battery monitor IC (STC3115) which measures current as well as voltage. the LTC4155 is absolutely awesome, it has dual supply inputs (5V in and USB-OTG), it can be turned round to *supply* 5V USB-OTG, *and* it can provide up to 3A @ 5V as system output. all three PCBs will be double-sided 2 layer, with components only on one side. cheap and cheerful. PCB3 will need to be 2oz copper because it's dealing with 4 to 5 amps in places. PCB1 is deliberately huge so that i have plenty of space to work with. i have had to do a little bit of rearranging so that there are less wires crossing over - for example, the MicroSD and the USB (CM108AH) Headphone jack have now swapped places. as a result, the micro-sd wires can run directly on the TOP layer - without crossing anything (especially USB traces). previously, the MicroSD lines would have had to cross over the USB audio lines. in a 4 layer PCB that's fine, because they're separated by an entire GND plane. in a 2 layer board? mmmm.... no :) so, now, the USB Hub is in the bottom left corner, the USB differential pairs go directly to the connectors (and to the USB Audio IC) - no crossing over... nothing. the SN75LVDS83b (LVDS converter IC) is... distinctly odd. it's extremely puzzlingly well designed. by placing it right next to the EOMA68 connector the 24-pin RGB/TTL outputs can be kept extremely short, with virtually no traces needing to cross over. even the LVDS differential pair outputs do not need to cross over to other layers: they may go directly to the LCD connector. PCB2 is the weird one: it's relatively large (3in x 5in L-shaped) but has an extremely low component count. i tried to use a 48-pin STM32F070, got even the PCB layout done, and realised that it just wasn't going to work: the multiplexing is just too tight, what with 24 of the pins used up for the 8x16 keyboard matrix. 4 more are needed for SPI, 2 for I2C, 5 more for GPIO, 2 for USB. btw - jaezzuss, last night it took 2 hours to go through all the connections of the keyboard with a multimeter, but it had to be done :) i needed to know the layout of the pinouts, and after experimenting pressing random keys i realised, with deep foreboding, that i *literally* had to go through absolutely every single key in turn, starting with ESC and ending at ENTER, putting a heavy object on every key and then manually scanning with a multimeter *all* 24 pins and recording the result. it turns out that yes it's a 16x8 layout. 8 bits vertical, 16 bits horizontal. there was very little pattern to the layout. a little bit of a pattern with the QWERTY keys and the numpad, but everything else pretty much completely defied logic! the idea here with the STM32F070 (which is very low cost btw) is that it will act as a USB-HID device. so, it will be necessary to provide power down one bank of 8 GPIOs, and to read 2 bytes of output from 16 GPIOs... that way you identify which keys are held down. the reason why i will have to go to the 64-pin QFP is because i don't want to use pins A0-A7 then B0-B4, C2-C3, then back to bank B for a bit.... i want to just use A0-A7, B0-B7, C0-C7 or whatever it takes, so that i can keep things very very simple: read one byte (register A), write one byte (register B) and so on. i haven't yet thought about what kind of interface to offer, when controlling the backlit 480x320 LCD, but that need not be of immediate concern. there is plenty of static RAM on-board the STM32F070 to make an on-board framebuffer. converting to USB-TTY (ACM) so that commands can be sent over a USB-serial port... this would tend to be the simplest way... it can all be taken care of later. btw, word of warning (to anyone else designing a laptop) - i've had to shuffle things around somewhat, significantly, based on what connectors could be obtained today (at reasonable prices). for example, FPC 24 pin 1mm "TOP Connect" wasn't available, so i had to use "Bottom Connect", which meant folding the keyboard's thin-film circuit connector into an S-Shape in order to fit it within the available space. this was to make sure that the connector could remain on the same side as all the other components on PCB2, otherwise it is more expensive to lay out the components on the PCB (you can't use solder reflow). you just can't predict absolutely everything - you can't expect absolutely everything to be available. sometimes you just have to adjust and work round problems. l.

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Vero Apparatus: Another Arm Laptop Project
by Alexander Stephen Thomas Ross 13 Aug '15

13 Aug '15

http://wiki.vero-apparatus.com/ leant of it via #neo900 on freenode thanks to edwin.

4 9

15.6in libre-hardware laptop prototype casework fully assembled
by Luke Kenneth Casson Leighton 07 Aug '15

07 Aug '15

http://rhombus-tech.net/community_ideas/laptop_15in/news/ ok, i'm done with major/minor details of the plastic, got something that "does the job", may need minor tweaking but for now it's done. woo! i'll celebrate tomorrow evening, i have a tennis match in the afternoon. next is to do the PCBs, whilst on the back burner sort out tape and a bezel for the LCD (and touchpanel), etc. etc. l.

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why i am persisting with this project
by Luke Kenneth Casson Leighton 07 Aug '15

07 Aug '15

several people have left this mailing list, or have become lurkers, or are no longer actively supporting the project, yet i am absolutely committed to it despite that. if you would like to know why that is, this is the reason: http://www.theautomaticearth.com/2015/08/deflation-debt-and-gravity/ l.

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Re: [Arm-netbook] 15.6in laptop progress
by Hans-Christian Jehg 27 Jul '15

27 Jul '15

>On Thu, Jul 23, 2015 at 9:03 PM, Philip Hands <phil(a)hands.com> wrote: > >>> then i began work on the friction hinge for the screen lid, so that >it >>> will remain upright. you'd think it would be easy to create an >> >> Nope ;-) > > you'd be right! > >> You could just not bother with a lock. > > yehhh the friction hinge isn't accurate enough, there's a few degrees >of play and that means the lid will be flapping by about... at least 1 >maybe even 2cm once wear sets in. > >> I have a Lenovo Thinkpad X230, and it has no lock on the lid. >> >> There is a slight impression that the lid snaps shut when almost >closed, >> but it's not clear if that's really the case. >> >> You could alternatively do some sort of rotating thing on the >corners, >> like the OLPC's wifi arials. > Magnet(s) to hold the lid closed? > ah! of course! nice idea... i don't hold out much hope (the screen >edge plastic is only 2.5mm thick as it is) - i'll try to drop it into >my tiny subconscious and see what happens over the next couple of >days. > >l.

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15.6in laptop progress
by Luke Kenneth Casson Leighton 23 Jul '15

23 Jul '15

is there no end to the detail that's needed?? okaay so i started on the screen edge, which (surprise) turned out to need to be thicker than anticipated. increasing the thickness by 2mm had a knock-on effect because, naturally, the base end depth has to be increased to match. then i began work on the friction hinge for the screen lid, so that it will remain upright. you'd think it would be easy to create an interlock between two pieces 8mm in diameter that looks aesthetic and is strong enough, but nooo i can tell you it damn well isn't :) now i am onto one of the final pieces of the puzzle: creating a lid lock. this needs to be spring-loaded (ball-point biro pen spring, cut into 1/4s 7mm long) and i am kinda amazed at how much detail is needed in such a small space. the clasp is 10mm x 9mm x 8mm but requires a 5mm diameter hole in the centre (for the spring)... we'll have to see how it works out. l.

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video of 15.6in laptop casework
by Luke Kenneth Casson Leighton 17 Jul '15

17 Jul '15

http://rhombus-tech.net/community_ideas/laptop_15in/news/ just created a 5min video describing the casework: the parts for the base are now completed, i will move onto the screen next. l.

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15.6in libre laptop "whoops"...
by Luke Kenneth Casson Leighton 14 Jul '15

14 Jul '15

oh dear, first mistake: hoping it's not too big a deal... i've done the base, now, and have moved on to doing the LCD screen holder parts. i forgot to check which side the connector is... turns out that when the screen's facing forwards the connector is on the *right*.... guess which side i put the main PCB? yep, on the left... so that shouldn't be so big a deal, right? just run the cable all the way along the back of the lcd until it pops out? noo problem, right? ... except it has to cross the middle part of the LCD, which is where there is a divider so that the left and right bamboo laminate panels can "lock" into place, and also so that the top and bottom channels can be divided into two (so they'll fit across a 200mm x 200mm 3d printer). the problem is in joining the parts together. previously i had thought to slot a little u-shape in place which would act as a trap: the ends of each of the U would "lock" into the left and right edges.... noo problem, right? except now there's a cable that has to go through exactly where that joining-piece was supposed to go. the other option: i was considering mirror-imaging the laptop base. put the PCB on the right, battery on the left.... except argh i remembered that i had to *offset* the touchpanel from centre (by about 30mm) in order to fit the battery to its right, and also fit PCB2 so that the keyboard connector goes into it.... all of this means that there is absolutely no way that the parts can be mirror-imaged: it's a near total redesign of the interior, and i'm certainly not doing that. sooo i have an eeenteresting mechanical design challenge left to think about.... :) l.

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Req: FOSS-restricting firmware hints
by Nico Rikken 08 Jul '15

08 Jul '15

Dear ARM-netbook and Coreboot readers, In FSFE context we're looking for examples regarding firmware restrictions on modern computer hardware. This so that we can shed light on the difficult situation you are all too familiar with. Examples are: - Trusted Platform Module (TPM) chips - Secure Boot - Intel - Management Engine - Advanced Management Technology - Boot Guard It will be great if you can add some from the top of your head, ideally including some references. I'll be doing my own research as well, but your hints will greatly help this process. Kind regards, Nico Rikken

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05 july 2015 laptop casework progress
by Luke Kenneth Casson Leighton 05 Jul '15

05 Jul '15

http://rhombus-tech.net/community_ideas/laptop_15in/news/ getting there. next is to do the right-hand edge, which will take the 3rd PCB (battery, power etc.). all sorts of small niggles, still have to check that the bamboo panels will fit, for example! need to get some battery samples to make sure that it'll fit, etc. etc.... l.

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