The ESP32 TTGO board using RIOT-OS

In the last few months, RIOT-OS operating system gained support for the ESP32 and ESP8266 based boards. RIOT-OS also supports several communication protocols, namely Lorawan through the usage of the Semtech implementation.

My post connecting the ESP32 TTGO board to TTN (The Things Network) describes (more or less) how to connect this board to the The Things Network using the Arduino and LMIC stack for the ESP32.

So why don’t give it a go with RIOT-OS?

Board definition:
RIOT-OS works with board definitions that describes several key features of the targeting board. In the case of the TTGO ESP32 Version 1 that I have several things needed to be changed from the base ESP32 board definitions that are available now on the RIOT-OS code base.

The most important issue was the clock speed definition for this ESP32 board, since it seems it uses a 26MHz clock instead of the standard(?) 40Mhz clock. Without the change for the clock speed all the serial output on the USB port was garbled and unreadable.

With the clock speed correctly set, important information regarding the pins for the I2C, SPI buses and the sx1276 chip needed to be defined. That was also correctly defined, and preliminary tests show that the Oled and sx1276 is detected using the Semtech Loramac stack.

I haven’t yet change the other pin definitions, so for the basic I2C, SPI, Button, and sx1276 are correctly defined.

The board definition can be found in my repository located at RIOT TTGO ESP32 repository under the directory boards.

To use this board definition, we just need to copy the board definition directory to the boards directory of the cloned RIOT-OS repository.

For testing we can just compile the examples under the example directory for the RIOT TTGO ESP32 repository.

There are two examples: One for testing the OLED screen and other to test the sx1276 and the Semtech Loramac stack.
This last example is based on the provided RIOT-OS example for Lorawan, but I’ve added support for ABP and debug prints to see what is going on.
On the Make file, we should select the type of activation and fill out the required data from the TTN device console. All data just needs to be copied and pasted directly and it should work.

To build the examples I’m using Docker according to this instructions.

Additionally, for the ESP32 flashing to work, the ESP-IDF repository must be cloned and its location set for RIOT build by setting the ESP32_SDK_DIR variable.

The following things work fine:

– The serial console works fine.
– The blue led, on and off
– The button, detecting it release and pressed.

The OLED works fine through I2C, but the I2C speed must be set exactly as defined on the board definition, otherwise it won’t work. It took me several hours to debug this issue.

The sx1276 works, it is detected and the Semtech stack seems to be able to use it. Adding some debugging to Loramac stack shows that the DIO# interrupts are detected but there are issues. For example I have two boards and with the same code I have different behaviours which seems rather strange… I was able to send data to the TTN gateway, but when waiting for the Semtech stack it hangs waiting for a stack status message. The other board is always complaining regarding MAC timeout.

So, all in all, as a first experience with RIOT-OS on the TTGO board, excepting the Lorawan stack, everything seems to work as expected. Regarding the Lorawan stack, probably going to try the LMIC Arduino implementation to see if it is possible to port it to RIOT-OS.


SDRPlay, CubicSDR on Arch Linux

This is just a simple post for writing the instructions for installing and using SDRPlay RSP1A (Should work for other versions) and CubicSDR on Arch Linux. I’ve previously installed most of the supporting software manually on my PC, and also had trouble installing the SDRPlay driver on Arch Linux with the SDRPlay installer on my PC. Since I have a lot of QRM (Noise) in my home, the next step was to use a portable computer to move the SDRPlay outside.

So, the following instructions are much more streamlined, since all the required software is on the AUR repositories, and so no “hacking” is needed.

Installing yay AUR package manager
If necessary we should install a AUR package manager. There are several ones, but as far as I’m aware, for now the yay is the currently maintained AUR package manager:

git clone
cd yay
makepkg -si

We can now use yay.

Installing CubicSDR with SDRPlay support:
If before installing CubicSDR we install HamLib support we will have a new menu on CubicSDR for rig control, otherwise it wont appear.
Then we need to install the SDRPlay driver, Soapy support and also CubicSDR.

yay -S hamlib
yay -S libsdrplay
yay -S soapysdr-git
yay -S soapysdrplay-git
yay -S soapyremote-git
yay -S soapyrtlsdr-git
yay -S cubicsdr-git

I’ve also added support for remote devices and the ubiquitous RTLSDR dongles.
CubicSDR will take a while (20 minutes, it will depend how fast is your computer) to compile, mainly because of the wxgtk widgets.

After it ends just connect the SDRPlay to the computer USB port, and execute CubicSDR. If the SdrPlay does not appear on the device list, press the Refresh button:

And that’s it, no fuss install, at least for me.

ESP32 TTGO board and Nordic Thingy:52 sensor device

The Nordic Thingy:52 is a 40€/50€ device based on the nRF52832 Nordic microcontroller that has, in a ready to use package, several environmental sensors, that can be accessed by low power Bluetooth (BLE). Nordic provides a complete solution that comprises the Thingy:52 firmware already flashed on the device (Source at GitHub) and an very nice Android Nordic Thingy:52 application, with also sources available at GitHub.

Anyway I have some of these devices for some months now, for other uses, but I decided to test the ESP32 based boards, since the ESP32 has Bluetooth and theoretically can connect and gather gather data from the Thingy. So this post is about the use of the TTGO ESP32 Lora based boards with an OLED to gather data, show it on the OLED, and send it to The Things Network. Seems simple, right?

So when a application connects to the Thingy:52 it can be notified when a sensor value changes throught the standard BLE notification mechanisms. The way the Thingy firmware works, this notification happens at a fixed intervals instead of a value change, and that interval, 5 seconds, 10 seconds, be defined by the Android App or programmatically by our application.

The application is developed by using the PlatformIO and for using the ESP32 Bluetooth interface, I’ve used the NKolban ESP32 BLE Library that happens to be library 1841 at the Platformio repository.

To cut a long story short, as still of today, the ESP32 BLE library doesn’t work correctly with the Thingy:52 notifications. This means that the application subscribes to have notifications, but those never happen. Fortunately someone already hit this problem and solved the issue, but the correction still hasn’t hit the library.

So basically to have my code example to work the following steps are needed:

  1. 1. Clone the TTGO ESP32 repository from . The repository uses the PlatformIO to build the application.
  2. 2. At the root of the repository run the command pio run so that the libraries are downloaded and installed.

At this point we need to correct the Arduino ESP32 library to add the patch to the notification issue.
Just execute the command:

[pcortex@pcortex:ESP32_NordicThingy|master *]$ cd .piolibsdeps/ESP32\ BLE\ Arduino_ID1841/src

At this directory (.piolibsdeps/ESP32\ BLE\ Arduino_ID1841/src edit the file BLERemoteDescriptor.cpp and at around line 151 (the exact line number will probably change in the future) we must change the ::esp_ble_gattc_write_char_descr function parameters:

 * @brief Write data to the BLE Remote Descriptor.
 * @param [in] data The data to send to the remote descriptor.
 * @param [in] length The length of the data to send.
 * @param [in] response True if we expect a response.
void BLERemoteDescriptor::writeValue(
        uint8_t* data,
        size_t   length,
        bool     response) {
    ESP_LOGD(LOG_TAG, ">> writeValue: %s", toString().c_str());
    // Check to see that we are connected.
    if (!getRemoteCharacteristic()->getRemoteService()->getClient()->isConnected()) {
        ESP_LOGE(LOG_TAG, "Disconnected");
        throw BLEDisconnectedException();

    esp_err_t errRc = ::esp_ble_gattc_write_char_descr(
        length,                           // Data length
        data,                             // Data
    if (errRc != ESP_OK) {
        ESP_LOGE(LOG_TAG, "esp_ble_gattc_write_char_descr: %d", errRc);
    ESP_LOGD(LOG_TAG, "<< writeValue");
} // writeValue

We need to change the highlighted line to:

    esp_err_t errRc = ::esp_ble_gattc_write_char_descr(
        length,                           // Data length
        data,                             // Data

With this change, the code at my github repositories has a working example:

– The ESP32 connects to the Nordic Thingy:52 device.
– It programs the Nordic Device to notify sensor values each 5 seconds (in real use cases it should be much larger period)
– Current sensor data is shown on the serial terminal.

What needs to be done:
– When notified by the Thingy:52, the ESP32 shows the new data on the OLED screen (WIP – Work in progress).
– To keep the application obeying the ISM bands duty cycle, it collects the data, calculates the medium, and sends the data to the Things network each 10 minutes (Also work in progress).

Docker container web interface – Portainer and Riot-OS Development

This post is a follow up of starting up with RIOT-OS. To be able to develop with RIOT-OS an easy (and easier) way to do so is just to install docker and web UI docker interface Portainer to control docker.

So we will install Docker, Portainer, and finally the RIOT-OS building environment.

Installing Docker and Portainer, is an initial stepping stone for using the dockerized development environment for RIOT-OS, since I don’t want to install all the development environments in my machine.

Installing Docker:
On Arch-Linux is as simple as installing the Docker package using pacman, enabling the services and rebooting.
Basically we need to run, as root the following commands:

pacman -S docker
systemctl enable docker.service

After rebooting the following command should return some information

docker info

A sample output is:

Containers: 2
 Running: 0
 Paused: 0
 Stopped: 2
Images: 9
Server Version: 18.09.0-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog

Installing Portainer
Installing the Docker Portainer Web UI is as simple as:

docker pull portainer/portainer

To run Portainer a set of complete instructions on this page, but basically on the simplest way is:

$ docker volume create portainer_data
$ docker run -d -p 9000:9000 --name portainer --restart always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_data:/data portainer/portainer

We can now check if the docker image is up:

$ docker ps
CONTAINER ID        IMAGE                 COMMAND             CREATED             STATUS              PORTS                    NAMES
7a38ae7fc922        portainer/portainer   "/portainer"        4 seconds ago       Up 3 seconds>9000/tcp   portainer

Since I have already ran the Portainer container, the initial setting up steps when accessing the URL HTTP://localhost:9000 do not appear, but we need to choose:

  1. A set of credentials to use as de administrator for portainer
  2. The local machine registry to connect to the local docker containers.

1- At initial access we define an user and password:

Portainer Credentials

2- Then we connect to our local docker instance:
Portainer Local Docker

Press Connect and then we can now access our Docker instance from Portainer:
Portainer Main Screen

Pressing the Local Docker Connection we can now manage our docker resources.

Installing the build environment for RIOT-OS
We can do it by two ways:

From the command line:

docker pull riot/riotbuild

or use Portainer:

This container is very big, so we need to wait some time for the container image download. The command line shows in greater detail the download process.

After the image is downloaded, we can follow these instructions for building our apps using the docker container as the build environment.

After the image is installed:

To use is is as simple as going the the examples directory and do:


From this we are now able to build based RIOT-OS applications for several targets, including the ESP8266/ESP32.

As we can see we even don’t need to have a running container, just the image.

Arch Linux with full encrypted disk

So, I’ve bought a new light weight laptop, an HP Envy 13.3 1.2Kg I7, where I wiped out Windows 10 and installed Arch Linux.

Just for security reasons I’ve decided to do a full disk encryption install, including boot.

There are several instructions on the Web, including videos on youtube in how to do it, and so on this gist I have my instructions for the installation, based off course in other gists and instructions.

In this post is the configuration instructions that worked for me and also to allow better find from google/bing/ddg.

I REALLY recommend first to use a Virtual Box machine with EFI support enabled to test everything before doing it on a real machine.

# Arch installation on a HP ENVY 13 inch laptop (ah0006np part number: 16GB Ram, 512GB SSD)

Install Arch Linux with encrypted boot, root and swap filesystems and boot from UEFI, completly dumping Windows on the process.
No dual boot.
Windows, if necessary will be run on a Virtual Machine and re-use the Windows key that came with the laptop.

The configuration will be LVM on LUKS. Also a major difference from other tutorials is that the boot partition is also encrypted, and not a standard partition.

# Results do far:

– Disk encryption ok. GRUB boots slow (20s). Otherwise works fine.
– Wireless works ootb, but errors on dmesg output from time to time when high traffic.
– Sound and microfone works ok
– Webcam does work but needs configuration: See below at the end.
– Keyboard special keys work fine (brightness, Sound, Mute), including keyboard background lights, but F6 sound Mute Led does not work.
– Some screen corruption with the Intel Driver either SNA or UXA. Nouveau crashes, nvidia driver didn’t work. To be checked -> Issue with QT 5 and Konsole/Kate applications, not a Intel Driver issue.
– KDE SDDM doesn’t recover well if screen DPMS is activated. I’ve disable it so far to solve it.
– Suspend/resume works fine.
– Battery time so far, around 4/5 hours.

# Desired disk layout:

|ESP partition: |Boot partition: |Volume 1:       |Volume 2:       |
|               |                |                |                |
|/boot/efi       |/boot           |root            |swap            |
|               |                |                |                |
|               |                |/dev/vg0/root   |/dev/vg0/swap   |
|/dev/sda1      |/dev/sda2       +----------------+----------------+
|unencrypted    |LUKS encrypted  |/dev/sda3 encrypted LVM on LUKS  |

The final result is to have an Arch Linux Installation with full disk encryption and with a basic set of applications such as the KDE Plasma Desktop.

These instructions have several sources, namely:
and this WordPress post.

The installation process on this guide is for the Arch Linux installation onto an HP Envy 13, 16GB RAM with 512MB ssd laptop. This laptop comes with Windows 10 Home installed, and as far as my model goes, it comes with an Intel WiFi board and a WD Sandisk SN520 512GB NVME SSD.

The official Arch installation guide contains more details that you should refer to during this installation process.
That guide resides at:

## Boot from image

Download the archlinux-\*.iso image from and its GnuPG signature.
Use gpg –verify to ensure your archlinux-\*.iso is exactly what the Arch developers intended. For example
at the time of installation:

$ gpg --verify archlinux-2017.10.01-x86_64.iso.sig
gpg: Signature made Sun 01 Oct 2017 07:29:43 AM CEST using RSA key ID 9741E8AC
gpg: Good signature from "Pierre Schmitz "
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 4AA4 767B BC9C 4B1D 18AE  28B7 7F2D 434B 9741 E8AC

Currently the Arch ISO is archlinux-2018.11.01-x86_64.iso.

Burn the archlinux-\*.iso to a 1+ Gb USB stick. You can use the dd command, unetbootin or Etcher.

Connect the USB stick to the usb port and power on/cycle the machine to boot.
If your USB stick fails to boot, ensure that Secure Boot is disabled in your UEFI configuration.

Note: To access the BIOS on the Envy Laptop, turn on the laptop and press several times the ESC key or the F10 key to access the BIOS while the screen is black.
First I moved the boot order to have the USB boot at the top.
Then we need to disable the secure boot option and press F10 to save. Confirm saving it.

Attention now: There is a confirmation screen to really commit the secure boot option change. Enter the requested code and save.

After booting up:

Set your keymap only if not you are not using the default English keyboard.

$ loadkeys pt-latin1

We can now, if required backup the HP recovery partition, that I suppose is the Windows Install Media.

# Connect to the Internet.

Execute the wifi-menu command and select a Wifi network. On this HP Envy, the wireless card (Intel) was detected with no issues.

Check with the “ip a” command if there is network connection.

## Prepare your hard disk

In the next steps we will create necessary partitions and encrypt the main partition.

Find the correct block device

$ lsblk

In my case the correct block device (the NVME SSD of my laptop) is ‘nvme0n1’. (Depends on the machine)

Create and size partitions appropriate to your goals using gdisk.

$ gdisk /dev/nvme0n1

Press p to show the partitions.

In my case I have a 260Mb EFI partition, a 16MB Reserved Microsoft Partition, a 460GB partition and a 980MB and another 15GB partition.

From this point on, everything that is to be done, will destroy the disk data.

# Delete all partitions on disk

Use the d command to delete all partitions. Use d, then partition number. Repeat for all partitions

Press o to create the GPT.

Create three partitions: One for the EFI, one for boot and the other will be used to have the Arch Linux installation. To create a partition, press n:

1. Partition 1 = 512 MB EFI partition (Hex code EF00). Initial Sector: ; End: 512M; Type: EF00
2. Partition 2 = 1GB Boot partition (Hex code 8300)
3. Partition 3 = Size it to the last sector of your drive. (default) (Hex code 8E00 – Linux LVM Partition)

Review your partitions with the ‘p’ command.
Write your gdisk changes with ‘w’.

Check again the names with the blkid command to know the partitions name:

1. EFI: /dev/nvme0n1p1
2. BOOT: /dev/nvme0n1p2
3. Arch: /dev/nvme0n1p3

# Create filesystems
The EFI filesystem must be FAT32:

$ mkfs.vfat -F 32 /dev/nvme0n1p1

The other filesystems are to be encrypted.

(optional) Before creating the partitions we can use the command

cryptsetup benchmark 

to see how fast the different encryption algoritms are.

# Encrypted /boot partition

$ cryptsetup -c aes-xts-plain64 -h sha512 -s 512 --use-random luksFormat /dev/nvme0n1p2
$ cryptsetup open /dev/nvme0n1p2 cryptboot
$ mkfs.ext4 /dev/mapper/cryptboot

The first command will ask for the disk passphrase. Do not forget it!.

The first crypsetup command will set the LUKS with default iter-time parameters, which may or may not make grub to boot slow (around 20s). If this is not fine add the following parameter: –iter-time=5000 (This will affect security, so use a large key phrase)

The last command will create a /dev/mapper/cryptboot device.
We can check that it was created with the command ls /dev/mapper

# Create encrypted LUKS device for the LVM

cryptsetup -c aes-xts-plain64 -h sha512 -s 512 --use-random luksFormat /dev/nvme0n1p3
cryptsetup open /dev/nvme0n1p3 cryptlvm

## Create encrypted LVM partitions

These steps will create the required root partition and an optional partition for swap.
Modify this structure only if you need additional, separate partitions. The sizes used below are only suggestions.
The VG and LV labels ‘ArchVG, root and swap’ can be changed to anything memorable to you. Use your labels consistently, below!

$ pvcreate /dev/mapper/cryptlvm
$ vgcreate ArchVG /dev/mapper/cryptlvm
$ lvcreate -L +16G ArchVG -n swap
$ lvcreate -l +100%FREE ArchVG -n root

Again, we can see on /dev/mapper if the logical volumes where created.

## Create filesystems on your encrypted partitions

$ mkswap /dev/mapper/ArchVG-swap
$ mkfs.ext4 /dev/mapper/cryptboot
$ mkfs.ext4 /dev/mapper/ArchVG-root

Mount the new system

mount /dev/mapper/ArchVG-root /mnt
swapon /dev/mapper/ArchVG-swap
mkdir /mnt/boot
mount /dev/mapper/cryptboot /mnt/boot
mkdir /mnt/boot/efi
mount /dev/nvme0n1p1 /mnt/boot/efi

# Install the Arch system

This installation command provides a decent set of basic system programs which will also support WiFi when initally booting into your Arch system.

At this point we need to have a network connection. Since the HP only has Wifi connection, we need to setup the WiFi connection. Other alternative is to use an Ethernet USB dongle that is recognized by the Arch boot iso.
Also, if you are behind a proxy, you can set the http_proxy and https_proxy variables to access the internet.

(Optional) Use reflector to speedup download (credit goes to u/momasf)

Change COUNTRY to (surprise) your country name.

pacman -Sy reflector
reflector --country 'COUNTRY' --age 12 --protocol https --sort rate --save /etc/pacman.d/mirrorlist

I won’t install base-dev here to save time at the installation.

$ pacstrap /mnt base grub-efi-x86_64 efibootmgr dialog wpa_supplicant vim

# Create and review FSTAB
The -U option pulls in all the correct UUIDs for your mounted filesystems.

 $ genfstab -U /mnt >> /mnt/etc/fstab
 $ nano /mnt/etc/fstab  # Check your fstab carefully, and modify it, if required.

Enter the newly installed system

$ arch-chroot /mnt /bin/bash

Set the system clock, you can replace UTC with your actual timezone

$ ln -fs /usr/share/zoneinfo/Europe/Lisbon /etc/localtime
$ hwclock --systohc --utc

Assign your hostname

$ echo mylaptop > /etc/hostname

My requirements for the locale are:
– Metric system
– 24h time format
– dd/mm/yyyy date format
– Portuguese language
– A4 paper size
– But all help, error messages are in English

The *pt_PT.UTF-8* plus *en_US.UTF-8* locale meets those requirements. To set up this locale:

– In /etc/locale.gen

en_US.UTF-8 UTF-8
pt_PT.UTF-8 UTF-8

– In /etc/locale.conf, you should **only** have this line:


We will change other settings on Bash profile.

Now run:

$ locale-gen

Create a new file vconsole.conf so that the console keymap is correctly set at boot. Create the file and add the following line:


Set your root password

$ passwd

Create a User, assign appropriate Group membership, and set a User password.

$ useradd -m -G audio,games,log,lp,optical,power,scanner,storage,video,wheel -s /bin/bash memyselfandi
$ passwd memyselfandi

Configure mkinitcpio with the correct HOOKS required for your initrd image

$ nano /etc/mkinitcpio.conf

Use this HOOKS statement: (I’ve moved keyboard before keymap, encrypt and so on…)

HOOKS="base udev autodetect modconf block keyboard keymap encrypt lvm2 resume filesystems fsck"

Generate your initrd image

mkinitcpio -p linux

## Install and configure Grub-EFI
Since we have the boot partition INSIDE the encrypted disk, we need to add the following option to the Grub options:

Edit the file /etc/default/grub and uncomment the following line:


And then we can install Grub, which will create an EFI entry named ArchLinux

grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ArchLinux

Edit /etc/default/grub so it includes a statement like this:

GRUB_CMDLINE_LINUX="cryptdevice=/dev/nvme0n1p3:cryptlvm resume=/dev/mapper/ArchVG-swap i915.enable_guc=3"

I’ve also added the i915 configuration line.

Other way of doing it is to use UUID:

blkid /dev/nvme0n1p3 -s UUID -o value

And use the UUID outputed on this command line:

GRUB_CMDLINE_LINUX="cryptdevice=UUID=55994-XXXX-xXXXX-XXXXX:cryptlvm resume=/dev/mapper/ArchVG-swap"

Generate Your Final Grub Configuration:

$ grub-mkconfig -o /boot/grub/grub.cfg

At this point there are some errors regarding failing to connect to lvmetad, which are normal and can be ignored.

# Mounting /boot without password request
Grub will ask for passwords to access the encrypted volumes. We can do this automatically:

dd bs=512 count=8 if=/dev/urandom of=/etc/key
chmod 400 /etc/key
cryptsetup luksAddKey /dev/nvme0n1p2 /etc/key
echo "cryptboot /dev/nvme0n1p2 /etc/key luks" >> /etc/crypttab

# Mounting root LVM without password prompt

dd bs=512 count=8 if=/dev/urandom of=/crypto_keyfile.bin
chmod 000 /crypto_keyfile.bin
cryptsetup luksAddKey /dev/nvme0n1p3 /crypto_keyfile.bin
sed -i 's\^FILES=.*\FILES="/crypto_keyfile.bin"\g' /etc/mkinitcpio.conf
mkinitcpio -p linux
chmod 600 /boot/initramfs-linux*

The mkinitcpio.conf FILES line will look like:


# Enable Intel microcode CPU updates (if you use Intel processor, of course)

pacman -S intel-ucode
grub-mkconfig -o /boot/grub/grub.cfg

# Check EFI Boot Manager
Check that the EFI Boot manager has the ArchLinux entry:

$ efibootmgr

For example if ArchLinux entry is Boot0003, check if on the boot order, 0003 is on the head of the list.
If not change the order with:

$ efibootmg -o 0003,0002,0001,0000

Exit Your New Arch System

$ exit

Unmount all partitions

$ umount -R /mnt
$ swapoff -a

Reboot and Enjoy Your Encrypted Arch Linux System!



# Setup system

We need again to connect to the internet, so run again the *wifi-menu*.

Install bash completion for reduced typing effort and other packages if necessary:

$ pacman -S sudo bash-completion base-devel git

To be able to use sudo from your normal user add wheel to sudoers.

$ EDITOR=nano visudo

Uncomment the line

%wheel      ALL=(ALL) ALL

From this point on, it really depends of what need there is for the machine.

# Making the webcam to work.
The webcam id appears at the lsusb output:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 8087:0a2a Intel Corp. 
Bus 001 Device 002: ID 04ca:7090 Lite-On Technology Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The webcam is the Bus 001:002 device: ID 04ca:7090.
Add the following rule at /etc/udev/rules.d

KERNEL=="video[0-9]*", SUBSYSTEM=="video4linux", SUBSYSTEMS=="usb", ATTRS{idVendor}=="04ca", ATTRS{idProduct}=="7090", SYMLINK+="video-cam"

Load the module to activate the webcam:

modprobe uvcvideo

The /dev/video0 and 1 devices should appear.

A simple start with the RiotOS operating system for IoT devices

The RiotOS operating system is an Open Source operating system that targets different embedded platforms while allowing to use the same code base for some aspects of IoT development: Connectivity, protocols and security. It also supports other key aspects such as threads, Inter process communication, synchronization support on the kernel side. It also supports several communications protocols, suche BLE, 6LoWPAN, Lorawan, and so on.

At the target level for the RiotOS operating system, RiotOS supports a wide scope of different platforms, including a special native platform. What does this means? It means that within certain limitations, it is entirely possible to develop an IoT application that runs where the code is developed, this includes our PC and any SBC such as the RaspberryPI. This support opens a new window of opportunities where it is possible to integrate different classes of devices, such as Arduino, STM32 and RPI while leveraging the knowledge on the same supporting code base.

How to start:

This is a very quick start instructions for building a native demo application with network support. As usual all the instructions apply to a Linux Operating system, in my case Arch Linux.

Clone the RiotOS repository:

Just run:

cd /opt
git clone

I’ve chosen the /opt directory for the sake of example.

Compile one the example application:

All example applications are under the example applications.
In each directory, there is a Makefile file with a specific content.

For example on the examples/default there is Makefile that targets the native environment.

Of key interest is the line in this file that defines the target board:

BOARD ?= native

If the BOARD variable is not defined on the running environment it will use the native board.

We just need now to run the make command:

[pcortex@pcortex:default|master]$ make
Building application "default" for "native" with MCU "native".

"make" -C /opt/RIOT/boards/native
"make" -C /opt/RIOT/boards/native/drivers
"make" -C /opt/RIOT/core
"make" -C /opt/RIOT/cpu/native
"make" -C /opt/RIOT/sys/shell
"make" -C /opt/RIOT/sys/shell/commands
   text    data     bss     dec     hex filename
  88189    1104   72088  161381   27665 /opt/RIOT/examples/default/bin/native/default.elf

We can see that the compilation output was placed at /opt/RIOT/examples/default/bin/native/default.elf.

But if we ran the default.elf executable, we get:

[pcortex@pcortex:default|master]$ bin/native/default.elf 
usage: bin/native/default.elf  [-i ] [-d] [-e|-E] [-o] [-c ]
 help: bin/native/default.elf -h

    -h, --help
        print this help message
    -i , --id=
        specify instance id (set by config module)
    -s , --seed=
        specify srandom(3) seed (/dev/random is used instead of random(3) if
        the option is omitted)
    -d, --daemonize
        daemonize native instance
    -e, --stderr-pipe
        redirect stderr to file
    -E, --stderr-noredirect
        do not redirect stderr (i.e. leave sterr unchanged despite
        daemon/socket io)
    -o, --stdout-pipe
        redirect stdout to file (/tmp/riot.stdout.PID) when not attached
        to socket
    -c , --uart-tty=
        specify TTY device for UART. This argument can be used multiple
        times (up to UART_NUMOF)

A little side note, under bin there is a native directory but if we target the compilation to a different platform, a new directory under bin will be created to that platform.

Returning to result to the above command, we notice that the command requires a TAP (terminal interface point) interface. The fact is that the RiotOS code to access the network resources of the hosting operating system doesn’t access the network interface directly, but does it through the TAP interface. We can create only one TAP interface, or several TAP interfaces, which in such case, means that we can have several RiotOS applications using an TAP based network to communicate between themselves and also with the external network. Neat!

RiotOS offers a script to the TAP intefaces, but before running the script, just make sure if any Linux operating system Kernel was done recently, a reboot migh be needed to the interfaces be successfully created.

[pcortex@pcortex:RIOT|master]$ ip a

1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp6s0:  mtu 4000 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:24:8c:02:dd:7e brd ff:ff:ff:ff:ff:ff
    inet brd scope global noprefixroute enp6s0
       valid_lft forever preferred_lft forever
    inet6 fe80::224:8cff:fe02:dd7e/64 scope link 
       valid_lft forever preferred_lft forever

Now we run the tapsetup script that creates the TAP interfaces. This script when called without any parameters, it creates two TAP interfaces. If we pass the -c argument with a number, for example -c 4, it will create 4 TAP interfaces. The -d parameter deletes all interface that where created.

[pcortex@pcortex:tapsetup|master]$ pwd
[pcortex@pcortex:tapsetup|master]$ sudo ./tapsetup 
creating tapbr0
creating tap0
creating tap1
[pcortex@pcortex:tapsetup|master]$ ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp6s0:  mtu 4000 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:24:8c:02:dd:7e brd ff:ff:ff:ff:ff:ff
    inet brd scope global noprefixroute enp6s0
       valid_lft forever preferred_lft forever
    inet6 fe80::224:8cff:fe02:dd7e/64 scope link 
       valid_lft forever preferred_lft forever
8: tapbr0:  mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 2e:bd:d8:88:64:55 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::2cbd:d8ff:fe88:6455/64 scope link 
       valid_lft forever preferred_lft forever
9: tap0:  mtu 1500 qdisc fq_codel master tapbr0 state DOWN group default qlen 1000
    link/ether 9a:a0:bc:fa:c7:61 brd ff:ff:ff:ff:ff:ff
10: tap1:  mtu 1500 qdisc fq_codel master tapbr0 state DOWN group default qlen 1000
    link/ether 2e:bd:d8:88:64:55 brd ff:ff:ff:ff:ff:ff

We can see that both tap0 and tap1 where created and are down.

Within two different windows we can run the default.elf with each interface now:

Window one: > sudo ./default.elf tap0
Window two: > sudo ./default.elf tap1

The two instances will start communicate and the tap interface have addresses and are up now.

11: tapbr0:  mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 0e:db:a6:77:3b:e5 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::cdb:a6ff:fe77:3be5/64 scope link 
       valid_lft forever preferred_lft forever
12: tap0:  mtu 1500 qdisc fq_codel master tapbr0 state UP group default qlen 1000
    link/ether 0e:db:a6:77:3b:e5 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::cdb:a6ff:fe77:3be5/64 scope link 
       valid_lft forever preferred_lft forever
13: tap1:  mtu 1500 qdisc fq_codel master tapbr0 state UP group default qlen 1000
    link/ether be:65:4f:4d:a0:ed brd ff:ff:ff:ff:ff:ff
    inet6 fe80::bc65:4fff:fe4d:a0ed/64 scope link 
       valid_lft forever preferred_lft forever

The above is a simple example, but RiotOS offers several examples including COAP, MQTT-SN and OpenThread examples.

The next step is to test RiotOS on ESP8266 and ESP32.

SdrPlay and ArchLinux

I’ve used the RTLSDR usb cheap dongles for a while for radio spectrum listening and scanning, but the fact is that in my case, they all are garbage. Yes they work fine for bands above 200/250Mhz (not too much noise there), but below that, my nearby powerful FM stations, overload the dongle and I can’t get much out of them (Even with a home made FM notch filter). Also in most cases, to hear HF bands (80m/40m/20) a hack (Q branch sampling) or an upconverter is needed, but still the FM stations blank out the other signals.

So for a bit of more money, I’ll give SDRPlay a go, since it is a full spectrum SDR (1.5Mz to 2GHz with a 10Mhz scope band) and also it can be used successfully as a pan adapter for Amateur band radios.

While waiting for my SDRPlay to arrive, and since the SDRUno program doesn’t run on Linux (I have Arch Linux), I started to get the software ready to use the SDR device with CubicSDR.

The software needed to access the SdrPlay devices in Linux is SoapySDR, the SDRPlay Driver for SoapySDR, and of course Cubic SDR. Also needed is the binary driver (yes I know… ) API/HW Driver – v2.13 to be installed.

While there are a lot of instructions to compile SoapySDR and Cubic SDR, including mine: Cubic SDR and SoapySDR, and a also very good video from SDRPlay I had a problem with the SoapySDRPlay component.

As we will se the problem is not with the SoapySDRPlay component but with the installation of the binary proprietary driver.

Basically during the binary driver installation I had the following output:

Press y and RETURN to accept the license agreement and continue with
the installation, or press n and RETURN to exit the installer [y/n] y
./ line 17: arch: command not found
API Version: 2.13
Remove old libraries...
Install /usr/local/lib/
cp: cannot stat '/': No such file or directory
chmod: cannot access '/usr/local/lib/': No such file or directory
Remove old header files...
Install /usr/local/include/mirsdrapi-rsp.h
Udev rules directory found, adding rules...
Libusb found, continuing...

If we continue with this situation (the cp: cannot stat ‘/’: No such file or directory
chmod: cannot access ‘/usr/local/lib/’: No such file or directory
errors), the SoapySDRPlay compilation will fail:

[ 20%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Registation.cpp.o
[ 40%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Settings.cpp.o
[ 60%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Streaming.cpp.o
[ 80%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Version.cpp.o
make[2]: *** No rule to make target '/usr/local/lib/', needed by ''.  Stop.
make[1]: *** [CMakeFiles/Makefile2:68: CMakeFiles/sdrPlaySupport.dir/all] Error 2
make: *** [Makefile:130: all] Error 2

To solve this we need to correcly install the driver, that in my case was the failure of copying the binary blob to the correct location.

So all we need is to go the directory where the binary installation is and create a working directory:

mkdir work
/ --target work

So the driver will install but in the working directory will be the missing driver to copy to the correct location:

sudo cp work/x86_64/ /usr/local/lib


I’ve also added to my home directory .bashrc file the following line to allow the new libraries to be found:

export LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH

And then just do a source .bashrc so that changes take place.

We can now compile SoapySDRPlay with success:

Scanning dependencies of target sdrPlaySupport
[ 20%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Registation.cpp.o
[ 40%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Settings.cpp.o
[ 60%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Streaming.cpp.o
[ 80%] Linking CXX shared module
[100%] Built target sdrPlaySupport

Execute the usual sudo make install and running the SoapySDRUtil command, the new driver should be available:

SoapySDRUtil --info
##     Soapy SDR -- the SDR abstraction library     ##

Lib Version: v0.7.0-g37429d89
API Version: v0.7.0
ABI Version: v0.7
Install root: /usr/local
Search path:  /usr/local/lib/SoapySDR/modules0.7
Module found: /usr/local/lib/SoapySDR/modules0.7/  (0.5.0-6efb692)
Module found: /usr/local/lib/SoapySDR/modules0.7/  (0.2.5-ad3d8e0)
Module found: /usr/local/lib/SoapySDR/modules0.7/ (0.1.0-12c3db6)
Available factories... remote, rtlsdr, sdrplay
Available converters...
 -  CF32 -> [CF32, CS16, CS8, CU16, CU8]
 -  CS16 -> [CF32, CS16, CS8, CU16, CU8]
 -  CS32 -> [CS32]
 -   CS8 -> [CF32, CS16, CS8, CU16, CU8]
 -  CU16 -> [CF32, CS16, CS8]
 -   CU8 -> [CF32, CS16, CS8]
 -   F32 -> [F32, S16, S8, U16, U8]
 -   S16 -> [F32, S16, S8, U16, U8]
 -   S32 -> [S32]
 -    S8 -> [F32, S16, S8, U16, U8]
 -   U16 -> [F32, S16, S8]
 -    U8 -> [F32, S16, S8]

We can see now that the module is loaded.

So who ever encounters the issue that I had, hopefully this will be the solution since the sdrplay binary installation scripts might fail.