TERES I DIY Open Source Hardware Modular Hacker’s Laptop update

teres

TERES-I DIY laptop first shipments started in September last year and we quickly sold the first initial production run. Immediately we start to get valuable feed back. Meantime the spare parts now are online and can be ordered.

FEEDBACK

Some of the feed back was quite pleasant like this one sent from Martin Krastev:

Здравейте,

Този път ви пиша не с въпроси по подръжката, а като потребител на Терес с
няколкоседмичен опит и впечатления ; )

Знам, че по идея Терес-А64 е бил замислен като хакерски ноутбук, но вече
седмици го ползвам като машина за разработка:
1. Освен проектите, по които работя, Терес сам си компилира и
компилаторите, които ползвам — 2-та ГБ памет наистина правят паралелното
компилиране възможно, та дори да е само -j2 или 3 (нещата, които компилирам са сравнително тежки, и по-голяма паралелност вече опира до суоп файла).
Така че голямо благодаря за ъпгрейда на паметта!
2. Въпреки нищожното охлаждане на чипа, Терес успва да държи по-голяма част от времето 1152МХц, което беше много приятна изненада за мен.
3. Клавиатурата се оказа доста ергономична, въпреки че в началото имах
опасения, че ще е малка.
4. Избора на чип от програмна гледна точка също се оказа удачен – някои
прозиводители на А53-базирани чипове орязват архитектурни фийчъри (демек – инструкции), но allwinner не са от тях (за изненада! ; ) Това ми позволява да не се тервожа, че код писан за по-глеми армове може да не тръгне на Терес.
5. Батерията носи добре на натоварване – дълги компилации не угасват по
средата! : ) А и шината за sd карти държи прилична скорост – напъно
сравнима с вътрешния флаш (при прилична карта, разбира се), така че и
проблемът с допълнително дисково пространство за големи проекти е решен.

Ами това е засега! Исках само да ви кажа, че с Терес сте в правилната
посока, тъй както сте създали напълно ползваем работен ноутбук за арм
програмисти, което си е постижение!

Поздрави,
Мартин

Google translate does satisfactory translation so I would not challenge my English translation skills 🙂

ISSUES

There were two issues we couldn’t catch during our tests and went with the first lot to our very impatient customers:

1. LCD backlight, some LCDs cause the backlight circuit inductor L11 to resonance at annoying audible high pitch harmonic frequency caused by the 300Hz PWM.

zoomIMG_20171219_083219

According to best Murphy’s law practices this problem didn’t show at the first few laptops we build and tested, but when we shipped the first lot some people complained back about it, so we had to find quick solution.
1.1. adding bigger capacitor 100 uF in parallel to C204 was solving completely the issue, but the boards were already produced and shipped to customers;
1.2. adding double adhesive tape which to press the L11 to the plastic cover solved the issue in most of the cases, if this was not enough sealing the L11 with superglue also stopped the noise, which was caused by L11 vibrations, needless to say this was quick dirty and messy fix

Инфорамция как да ъпгрейднем фърмуер на touchpad и бутони:

This issue was completely fixed with adding 100uF to second production lot

2. Touch panel buttons issue. We run out of GPIOs on the keyboard board so ADC was used to scan these two buttons. Again everything was OK when we tested the few laptops we assembled in house, but soon after the shipment people start complaining that sometimes they press left button but laptop register right button and etc, quite annoying!
2.1. the problem was partially fixed with changing the firmware, we posted new keyboard PCB firmware and instructions on GitHub but this not always solved the problem
2.2. the good fix solution was to decrease the resistor values on the PCB and use 1% precision resistors instead of 5% used initially

We do apologize to all customers who had experienced such problem, we guess they are not many, but if someone has still such issue after the firmware upgrade we will send free PCB3 replacement, just please send us your requests to support@olimex.com.

In the current KITS this issue is solved.

SOFTWARE

The initial version of the Linux software was not in best shape, the community helped us a lot and we are now on the third release. Special thanks to Alexey Korepanov for reporting lot of issues and fixes! He also made his own Gentoo distribution for TERES-I at GitHub!

PLASTICS

As you all know we suck at mechanical engineering and we had to find all plastic parts from Chinese laptop supplier. Some people asked about possible 3D designs of the laptop case but we are not capable to do this. So one of our customers Jeff Moe who obviously has mechanical engineering skills decided to re-design the plastics and make them as models in 3D printed format – he sends me pictures of his progress from time to time which I post here. So 3D makers be patient – there will be soon 3D printed designs and replacement parts for TERES!

EDIT: Jeff just noted me that the design is made by Brent MacKenzie from the Colorado Printing Project.

IMG_20180117_222635

IMG_20180118_101726IMG_20180118_182121

IMG_20180118_182208 (1)IMG_20180118_183356

It looks the LCD back plastic he designed is even easier to assembly than the original one.

IMG_20180118_190156

 

WHAT’s NEXT

I will post more in my next post about our progress in turning TERES-I DIY Laptop in portable lab with additonal FPGA board which makes from TERES component tester, Logic Analyzer and Digital Storage Oscilloscope with Sigrok.

TERES-I update. First feedback from our customers

magnet

Today we shipped all pending orders for TERES-I and we start to get valuable feedback from our customers!

First thing – we missed the magnet assembly in the instruction manual (blush). This leaded to laptops not go in suspend mode when lit is closed.

We updated this in the assembly manual 1.1 which is now on the web and included in the GitHub too in sources so people who notice typos and want to help improveing the Bulgarian-English language in which the manual is written.

Another issue reported immediately which we missed during our testing is that on small percentage of the laptops the LCD backlight step-up inductor cause annoying sound when LCD backlight is with 50% brightness.

BUZ

It’s a interesting phenomenia as the backlight PWM is 300Hz which is not possible to hear, but when LCD backlight is switch ON and OFF high current surges are happening and some harmonics cause mechanical resonance with this inductor.

The solutions may be few:

  • play with PWM frequency to get away from this frequency which cause the mechanical resonance – pure software approach which need lot of experimenting
  • adding small double adhesive matt on top of the inductor which make contact with the back plastic and this way absorb all vibrations – we start to add this mat as soon as we discover this issue to all laptops no matter if they buzz or not. Not very aestetish but quick and dirty solution:

ABS.jpg

  • Add more capacitors to the PWM power supply which to handle this current surge, adding 100 uF seems to remove the problem, but the first lot was already assembled and many laptops are already shipped – so this we will implement in the second assembly.

 

We have two reports about problems caused by the touch pad after “apt-get update / upgrade” we have to look more closely into this issue. For the moment we do not recommend you to update and upgrade your Ubuntu packages or if you do this and something stop working to revert to the original image – this is pretty easy just download the image write it to SD card, boot and run the eMMC copy script.

TERES I assembly workshop this Saturday!

workshop

This Saturday 21st of October we will have TERES I assembly workshop!

Customers from Bulgaria who placed orders for TERES I DIY Open Source laptop will have their laptop kits ready and are invited to come and we assembly them together!

The assembly workshop will be in OLIMEX Training Building and will start at 14.00 o’clock.

No need to have Laptop kit to participate, everyone is welcome to join us.

TERES-I DIY Open Source Hardware hacker’s Laptop update

keyb

It’s have been long time since I blogged about our laptop project.

What is the status – we have first PCBs prototyped and most of parts works fine.

We had to make Matrix keyboard + I2C touchpad to USB converter board. We did this with small AVR.

For this project we couldn’t use any of our standard connectors – we had to source all new: mini HDMI connectors, USB host connectors, power jack, audio jack connectors all they had to be low profile and embedded inside the PCB, hence this off form of the main PCB:

PCB

The LCDs used in laptops are not as the normal LCDs, they are very thin only 3mm or less and as their cable is special as must have as low as possible number of thin wires knitted together in very thin round cable, is has to go through laptop plastic’s hinges and normal cable can’t fit there. This is why all laptop LCDs are not parallel RGB neither LVDS but use eDP interface.

For bad luck A64 do not support such interface so we start to search LVDS/HDMI/RGB to eDP converter ICs. What we found is that Western suppliers solutions (TI etc) are more expensive than A64 chip itself so no go. We found Chinese solution for $1 NCS8801 and we said – well this is our solution 🙂 we made PCBs prototype and sourced few chips then we struggled by the lack of documentation 🙂 The ‘datasheet’ is 30 pages and the only code which is on the net initializes registers at addresses not mentioned in the datasheet, after spending almost 4 weeks on this we gave up and start looking for another solution. We found ANX6345 which is a bit more expensive but has some code in Linux Kernel and seems used with Rockchip ICs, so we hope this to solve LCD issue. We designed new board and got the new prototypes few days ago so they wait open window on assembly line to be assembled, crossing fingers everything to work 🙂

The mechanical parts has their history too. In June we placed orders to several different suppliers for the plastic parts, speakers, touchpads, power adapters, screws, hinges, total 40 different parts which are inside the laptop. The orders were complete in July and consolidated as one shipment on August 6 they were expressed with TNT and 2 days later were at Sofia airport, but the troubles just began 🙂

To import something may seems very easy for outsiders, but has it’s tricks. Usually every component can be classified in several positions in customs tariff, for instance LCDs have at least 7-8 different codes at which they can be imported, like they can be classified as display for computing equipment, as display for TV, as display for signage, as display for metal processing machine, etc etc. The trouble is that all these positions had different import tax 🙂 and of course Bulgarian customs try to force you to pay on the highest tariff code unless you prove them other. Another issue is that there work mostly people with economic education and very few know electronics matter. Import tax starts from 0% for computer parts and go up to 4-5% for TVs and machines, not small amount when you talk for $200 laptop parts! So laptop parts were sitting on customs 3 weeks as customs officers were trying to tariff every hinge, screw, plastic etc part as different product to tariff it with the highest code. Fortunately after 3 weeks of thinking somebody with common sense allowed all laptop spare parts to be imported as such with 0% tax and we got them today, but the fight will continue as this was only 10% of the order which we wanted to receive promptly paying expensive air transport, remain 90% parts still travel by sea and will arrive end of September, so let’s see how they will tariff these when arrive 🙂

We get lot of request when the laptop will be done and we love all our impatient customers 🙂

Guys be sure that we do anything humanly possible to release it as soon as we can, but to design something from scratch which you had never did before is not easy, once we do this I’m sure we will easily make 10 other laptops, but first time is always more difficult, to arrange logistic of so many parts and produce is not less challenging.

 

P.S. I hope you like the “Super” key on our new keyboard above 🙂