TERES-I update. First feedback from our customers


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.


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:


  • 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.

8 Comments (+add yours?)

  1. Riccio
    Nov 04, 2017 @ 01:58:01

    Regarding the audible range, 300Hz is heard: https://en.wikipedia.org/wiki/Hearing_range#Humans


  2. Ged
    Nov 05, 2017 @ 02:44:27

    PWMed backlight is not very eye-friendly and should not have been used in the first place. Please consider a constant-current solution for future designs!


    • Anton Zinoviev
      Nov 05, 2017 @ 12:14:49

      An alternative would be to use a higher frequency, 1.5kHz should be ok. I think that 300Hz (the frequency used by Teres 1) is above the average of the current laptops. At this frequency nobody (even the sensitive people) will be able to observe the flickering of the display. The effect, however, will be felt, especially with moving images. For example when the mouse cursor moves, our brain will not be able to predict properly its direction and expected position, or for some miliseconds will see many cursors. To some people such effect causes disorientation and headache, but most people won’t even realise the effect exists. They will perceive it as something normal and will be unaware of the slight fatigue it causes.


  3. Trackback: TERES-I update. First feedback from our customers https://olimex.wo… | Dr. Roy Schestowitz (罗伊)
  4. Nicolas
    Nov 15, 2017 @ 18:08:10

    What would the easiest way to get a non-US (specifically Danish) keyboard on the TERES be?


  5. Andrew Bernard
    Nov 16, 2017 @ 05:40:30

    I’m very much looking forward to ordering one of these shortly. In the meantime, I will revise and correct the manual, putting it into proper English for you (no disrespect intended). Happy to help!


  6. Anonycat
    Nov 18, 2017 @ 23:56:28


    Frankly, I am very disappointed from this laptop. No ethernet, WiFi without MIMO and no general purpose connectors so that I (and any hacker) can easily add his own addon cards for his own projects.

    E.g. if there was one or a couple of mini-pci connector(s) having only the USB connection, one could easily add an existing GSM/UMTS/LTE or GPS mini-pci/usb card. That would make much more sense than having all those useless USB ports from outside!

    Now you suddenly write that you added two connectors for a FPGA board. First of all I think this is just really stupid! You should have a connector designed to be a general extension connector and let the people decide what to do about it!

    And if you already have such a connector then PLEASE document it a put a link on the e-shop page! For me it may be the reason to still buy this laptop IF I can hack on it a make it usefull FOR ME. Which is not the case without these connectors (I badly need at least 100Mbit Ethernet and I would like to have some USB or UART internal connections to be able to extend the laptop for my needs).

    I must tell you that I don’t really get it what you meant to achieve with this laptop. As a laptop for a regular user this is just useless – too slow, to small RAM, too etc. It would only make sense as a laptop for hackers – but hackers need easily extensible interfaces in order to make their own projects – which you apparently didn’t count for. It’s REALLY pitty


    Nov 22, 2017 @ 05:57:02

    Anonycat – maybe you should look elsewhere? Or start your own project? Or…I don’t know, read the previously posted information that clearly addresses all of this asinine, whinging drivel I have just wasted my time reading!


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