Magic shield plates helps naked A20-OLinuXino-LIME2 board to pass CE EMC requirements.

Ax0-OLinuXino-LIME-1

A20-OLinuXino-LIME and A20-OLinuXino-LIME2 are choice for many industrial applications, when the board is inside metal box like BOX-LIME:

BOX-LIME-BLACK-1

it has no problems with shielding the radio emissions, but when just board is used as component, our customers has to shield it by their own in their designs. We had number of request to do official CE EMC certifications for A20-OLinuXino-LIME2 as this would make their life easier, and we decided to do this after we already get some experience with the certification of USB-ISO and ESP32-POE-ISO.

Initially the naked board failed on EMC measurements as seen here from the test results.

LIME2-naked

The major problem is the Gigabit Ethernet PHY. You can see spikes at 125 Mhz, 325Mhz etc. Disabling the PHY removes all noise and everything is in safe levels. So we knew who is ther trouble maker.

The major noise emitter are the Transmit and Receive clock lines. We put 33 ohm resistors in series R119 and R123 in A20-OLinuXino-LIME2 schematic , but obviously this was not enough. To further fade the line harmonics we replaced the resistors with 0402 Ferite Beads with 600 ohm impedance at 100 Mhz. This lowered the emissions, but still not well enough to be at safe levels.

So we had to make small Faraday cage on top:

LIME2-SHIELD-top

and bottom of the board:

LIME2-SHIELD-bot

this effectively removed all noises and the A20-OLinuXino-LIME2 pass CE requirements:

LIME2-1

LIME2-2

LIME2-3

LIME2-4

We are preparing now to implement the Ferite Beads on PHY Tx and Rx lines in all our other boards production assembly, and will offer the shield plates as kit they are good for A20-OLinuXino-LIME and A20-OLinuXino-LIME2 and we will prepare same for A20-OLinuXino-MICRO and A64-OLinuXino.

 

ESP32-ADF based SIP Phone looks really cool with LittlevGL

esp32-adf-sip1

We blogged a while ago about one of the demo code we work on for ESP32-ADF – SIP IP phone. Our vacation delay a bit this project, but now it’s almost ready and we want to share some details.

We used LittlevGL framework for the UI. You can see on the picture above how the phone app looks on the LCD.

LittlevGL required some touching as default didn’t work well with the touch screen, but we managed to add support, the touch panel recognize gestures like slide, tap etc.

esp32-adf-sip3

We need few more days to finish dialing sounds etc details and will upload on GitHub our patches for LittlevGL and our SIP IP phone demo.

We are so impressed with the result that we may release soon all in one LCD+ESP32-ADF and camera so we enhance the phone with camera and open more applications like Home automation WiFi Door-Phone, security panel with sound and video and other apps based on this configuration.

Product Change Notification feature is implemented on our web site so our customers can stay up to date with planned new features and board revision changes

Screenshot from 2019-08-20 16-00-08.png

Many of our customers asked us to implement Product Change Notification on our web, so they can subscribe and be notified when we start working on new revisions of our boards or when the new revision is in production together with the new features implemented.

Now we have it implemented as you can see on the picture above when you are in product page you can see small letter icon with red dot in the upper right corner, when you click on it you can subscribe for notification about this product.

 

New Debian 10 Buster images released for A20 and A64 boards and SOMs

buster

We have released Universal A20 and A64 images with Debian 10 Buster.

There are few known issues which we work on:

  • Certain types of eMMC memories might start in HS-200 mode instead of SDHS mode. This causes eMMC installation and boot problems.
  • HDMI always takes precendence over LCD. This is even if you have enabled a
    display manually (interrupted u-boot and executed “olinuxino monitor set XXX”).
  • Boards with 5.x eMMC chips are unable to boot directly from eMMC;
    this is caused by poor eMMC 5.x support in eGON BROM;
    this issue is not related to the Linux image
  • The board currently cannot store rootfs on usb driver. The init script
    starts before the usb subsystem initialization.
  • If the board has eMMC and SPI, it’s not possible to boot from SPI and rootfs
    on SATA. This is due to the fact that u-boot searches first the eMMC storage
    for boot scripts.
  • LCD-OLinuXino-15.6FHD is not fully supported.
  • The GT2005 camera module in A20-SOM-EVB and A20-SOM204-EVB is not working.

New release is preparing and will be updated by the end of the month.

 

 

New from our forum – experimental NixOS image for TERES DIY OSHW Laptop

nixos.png

Recent post from our forum explains how to build experimental NixOS image for TERES-I  – Do It Yourself, Environmental friendly, modular Open Source Hardware ARM Laptop.

ESP32-ADF Internet Radio example now uses LoBo with 2.8″ TFT LCD and touch screen

 

The Internet Radio demo for ESP32-ADF now includes MOD-LCD2.8RTP and LoBo for UI. Updated version is uploaded on GitHub.

Screenshot from 2019-07-30 17-01-30.png

Programming with open source hardware educational board eduArdu and Scratch 3

Screenshot from 2019-07-29 14-52-10

New demo code which transforms eduArdu in Makey Makey and tutorial how to use with Scratch 3 is uploaded to GitHub.

Here is the result from above code:

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