Embedded Systems

From Using a "proper" camera as a webcam there were some references to some interesting inexpensive high resolution cameras and lenses. I can't vouch for quality, but I intend to give them a try.

• C920/C922/C930 enclosure kit for CS-type lens mk2 - with some references to lenses and IR-cut filters
• IMX477 Full Report – Datasheet, Specs, Technologies and Camera Modules - f you are considering the Sony IMX477 or IMX477R, then this is for you. datasheets, specs, and related informaiton
• ArduCam embedded camera solutions on Amazon

There are suggestions for teleprompters in there as well.

I recently picked up some BeagleBoard Green devices to act as temperature/pressure/humidity/gas sensors with the BME680 sensor.

After proving everything works with an 'out-of-the-box' unit, the next step is to see how far this can be upgraded. The units I received are running Debian Buster (the now previously stable release).

There is a list of BeagleBoard.org Latest Firmware Images, which currently has newer Buster images, but with the GUI removed. This provides for more drive space for an upgrade cycle. (there was not enough space with the factory loaded image).

Installing consists of downloading the 'flasher' image, installing to an sdcard, power cycling the beagleboard, and allowing time for the re-flash to proceed. The notes indicate that:

• flashing takes power
• remove any sensors / attachments
• remove the ethernet as it has a power overhead
• connect to a power supply (I was attempting to use POE, and I'm not sure if that was adequate)

The programming notes suggest downloading an application called etcher to write the image to the sdcard. A much simpler way (from Instructions to flash an image to an SD card):

xzcat bone-eMMC-flasher-debian-10.3-iot-armhf-2020-04-06-4gb.img.xz | dd of=/dev/mmcblk0 bs=64k oflag=dsync status=progress

After the reflash, and a reboot, I found that quite a few packages could be updated.

apt-get update apt-get dist-upgrade

There is a note about Debian 11 (bullseye) Testing Images where the suggestion is to do an in-place dist-upgrade, or fall back to downloading an image from a testing repository.

It might be faster to download the image that it would be to download 651 packages and perform an installation.

It took a while, but the dist-upgrade worked. It did require a download only retrieval with a forced install for some firmware::

# apt -d install firmware-brcm80211         
# dpkg -i --force-overwrite firmware-brcm80211_20210315-3_all.deb 
(Reading database ... 88560 files and directories currently installed.)
Preparing to unpack firmware-brcm80211_20210315-3_all.deb ...
Unpacking firmware-brcm80211 (20210315-3) over (20190717-2rcnee1~buster+20200305) ...
dpkg: warning: overriding problem because --force enabled:
dpkg: warning: trying to overwrite '/lib/firmware/brcm/brcmfmac43455-sdio.clm_blob', which is also in package bb-bbai-firmware 1.20210923.2-0~buster+20211007
Setting up firmware-brcm80211 (20210315-3) ...

Then, to bring the kernel up to date:

# apt-get autoremove
#
# cd /opt/scripts/tools/
# git pull
# ./update_kernel.sh 
# ./update_kernel.sh --lts-5_10

The update is performed twice: once to perform a simple upgrade (which will provide options), and then use the latest option to get current

Something to try later is to run a script to flash, rather than using a special image to self-flash: Flash Debian Bullseye on your BeagleBone Black, with more info at Beagleboard:Updating The Software.

Guide: Installation of *VANILLA* Debian 11 (or later) on a Raspberry Pi 4 - check Debian Bug#985956

• Nitrogen 8M - boundarydevices.com/product/nitrogen8m/
• Solidrun Cubox M - shop.solid-run.com/product/SRMP8QDWB1D04GE008X00CE/
• Hummingboard Pulse - shop.solid-run.com/product-category/embedded-computers/nxp-family/hummingboard-m/
• Purism Librem 5 Phone - en.wikipedia.org/wiki/Librem_5
• Compulab SBC-iMX8X - www.compulab.com/products/sbcs/sbc-imx8x-nxp-i-mx-8x-single-board-computer/ - (supported since 5.4.24)
• Toradex Apalis iMX8 CoM - www.toradex.com/computer-on-modules/apalis-arm-family/nxp-imx-8

Enabled with CONFIG_ARCH_MXC=y in debian/config/arm64/config

Reflected in Debian Bug#985862

I can't remember the source of this, probably some sort of Debian bug entry:

FT4232H - Hi-Speed Quad USB UART IC is FTDI’s 5th generation of USB devices. The FT4232H is a USB 2.0 Hi-Speed (480Mb/s) to UART IC. It has the capability of being configured in a variety of industry standard serial or parallel interfaces.

Building from Android Source Code -- Android Open Source Project

The repo init command doesn't like some forms of NAT. A command like:

$ repo init  --depth 1 --no-clone-bundle  -u https://android.googlesource.com/platform/manifest

may stick at the following with 100% cpu:

 * [new tag]         v1.9.5     -> v1.9.5
 * [new tag]         v1.9.6     -> v1.9.6
Get https://android.googlesource.com/platform/manifest

When performing a debug, this is the stage where it is stuck (no idea how to fix it, ended up bypassing NAT):

$ repo --trace init  --depth 1 --no-clone-bundle  -u https://android.googlesource.com/platform/manifest
Geta https://gerrit.googlesource.com/git-repo
remote: Counting objects: 142, done
remote: Total 4158 (delta 2038), reused 4158 (delta 2038)
Receiving objects: 100% (4158/4158), 4.69 MiB | 519.00 KiB/s, done.
Resolving deltas: 100% (2038/2038), done.
From https://gerrit.googlesource.com/git-repo
 * [new branch]      maint      -> origin/maint
 * [new branch]      master     -> origin/master
 * [new branch]      stable     -> origin/stable
 * [new tag]         v1.0       -> v1.0
 * [new tag]         v1.0.1     -> v1.0.1
 * [new tag]         v1.0.2     -> v1.0.2
 * [new tag]         v1.0.3     -> v1.0.3
...
 * [new tag]         v1.8.2     -> v1.8.2
 * [new tag]         v1.9.0     -> v1.9.0
 * [new tag]         v1.9.1     -> v1.9.1
 * [new tag]         v1.9.2     -> v1.9.2
 * [new tag]         v1.9.3     -> v1.9.3
 * [new tag]         v1.9.4     -> v1.9.4
 * [new tag]         v1.9.5     -> v1.9.5
 * [new tag]         v1.9.6     -> v1.9.6
: git --version 1>| 2>|
: parsing /home/rpb/.gitconfig
Get https://android.googlesource.com/platform/manifest
: export GIT_DIR=/home/rpb/aosp/.repo/manifests.git
: git init 1>| 2>|
: git config --file /home/rpb/aosp/.repo/manifests.git/config --null --list 1>| 2>|
: git config --file /home/rpb/aosp/.repo/manifests.git/config --replace-all filter.lfs.smudge git-lfs smudge --skip -- %f 1>| 2>|
: git config --file /home/rpb/aosp/.repo/manifests.git/config --unset-all core.bare 1>| 2>|
: git config --file /home/rpb/aosp/.repo/manifests.git/config --replace-all remote.origin.url https://android.googlesource.com/platform/manifest 1>| 2>|
: git config --file /home/rpb/aosp/.repo/manifests.git/config --replace-all remote.origin.fetch +refs/heads/*:refs/remotes/origin/* 1>| 2>|
: git fetch --progress origin --tags +refs/heads/*:refs/remotes/origin/* +refs/heads/master:refs/remotes/origin/master 1>| 2>|
^Caborted by user

A few different sync command styles from AOSP repo sync takes too long:

$ repo sync  -f --force-sync --no-clone-bundle --no-tags -j$(nproc --all)
$ repo sync -c --no-tags --no-clone-bundle -j2
$ repo sync -c --no-clone-bundle

where -j2 is number of parallel processes to use, the other parameters require some description.

Android for Enterprise

• Android for enterprise in Platform Developers
• Build for Enterprise - overview
• Enterprise - Device Administration
• Android Enterprise Recommended
• Android Enterprise devices and service providers
• DevicePolicyManager - in developers

• Melexis at Mouser
• Melexis MLX90640 Far Infrared Thermal Sensor is a fully calibrated 32 x 24 pixel thermal IR array in a compact
• Excelitas CoolEYE IR Imagers
• AMG88x3,4 Grid-EYE® Sensor Datasheet
• 16 x 4 Infra-Red Array by McLaren Technologies

2018/11/09 - Three ports, even though they are labelled as wan, lan0, and lan1, all three exist on the same Topaz switch. Layer 3 functions on each port will probably work, but trying to make something like Open vSwitch handle packet switching between ports will not work (unless the hardware offload works, which I doubt). The Topaz switch takes care of all mac-learning and line forwarding. The three ports are not independent of each other.

2019/01/08 - I believe the Esspressobin has a Marvell® Link Street®-88E6341 switch. The switch has a Linux DSA configuration. This means that the Linux IPRoute2 utilities shouild be able to set VLAN parameters for each port. By setting each port to different VLAN, or set of VLANS, then all traffic should be forwarded to the CPU for routing/switching. If using open vswitch, ingress/egress vlans can be remapped to a common bridge if so desired.

Back to the original article:

Following along the Software HowTo information page, I was able to:

• Build system requirements - check
• Build from source - Toolchain - check
• Build from source - Kernel - check
• Build from source - Bootloader - check
• Build from source - Buildroot - build failure (due to SSL include issues), instead, downloaded pre-built from BuildRoot 2015.11
• Boot from MicroSD card/USB stick - Buildroot - check, with one caveat that I had to rename the dtb file and remove _v5_ I believe.

With those steps, I was able to get a successful boot to ensure the board was functional. I used 'screen /dev/ttyUSB0 115200' as a console connection command to the EspressoBIN.

Ultimately, I want a Debian bootable system. So, for experiment #2.... GitHub armbian/build has the instructions for building from scratch. But I opted for instant gratification with downloading and installing a pre-built image. Even though the instructions at armbian espressobin are terse, they are accurate in terms of what is needed to get a (as of this writing) Debian Stretch v4.18.y kernel installed on EspressoBIN. The FAQ describes how to burn an image to an SDCard (in my case Etcher on Linux). I disable NetworkManager.service, NetworkManager-wait-online.service, systemd-networkd and systemd-resolved. I then manually adjust /etc/network/interfaces. Armbian Documentation talks about special optimizations as part of the build.

• EspressoBIN Block Diagram
• GPIO as a character device
• libgpiod
• New GPIO Presentation
• GPIO Device driver along with a collection of other embedded topics
• Driving an LED from an 1.8V GPIO pin that defaults to “IN”
• 88F3710 and 88F3720 - ARMADA® 3700 Family Single/Dual CPU System-on-Chip Hardware Specifications
• GPIO Map
• EspressoBIN GPIO Pins

Other related:
• Debian Arm64Port/AArch64 - port of Debian to the 64-bit Arm platform (arm64), known in some other places as AArch64, info up to Stretch
• InstallingDebianOnMarvellESPRESSOBin
• Run UBOS on ESPRESSObin - is a Linux distro that aims to make it 10x easier to run server-side apps for yourself, or for your family, on hardware or cloud servers you own.
• build/config/bootscripts/boot-espressobin.cmd - u-boot boot script for armbian
• ondemand governor does not scale up the cpu frequencies as expected.
• armbian build with governor
• I/O Related testing parameters
• govenor settings
• marvell dts file
• firmware?
• reference document of using crypto-safexcel engine in 3720 and 7K/8K SOCs.
• Command to recompile script into .scr format, cmd - armada-3720-espressobin.dtb is for the mainline kernel
• openssl crypt testing - must be kernel compile, no crypto module shows up in lsmod
• checking for crypto
• booting from sata
• armbian-config menu to build from beta
• ptp build
• build with custom options
• through put on various interfaces
• Marvell Linux Porting Guide
• Linux Kernel Crypto API
• armbian boot and os downloads
• Armada A388, A3700 forums
• Add support for the ethernet switch on the ESPRESSObin
• Marvell EBU:Mainline Linux - status of the support in the official Linux kernel for Marvell EBU processors.

Commands to try:

• armbianmonitor -m
• iperf3
• lspc sysbench --test=cpu --cpu-max-prime=20000 run --num-threads=$(grep -c '^processor' /proc/cpuinfo)
• isysbench --test=cpu --cpu-max-prime=20000 run --num-threads=$(grep -c '^processor' /proc/cpuinfo
• cat /proc/cpuinfo
• cpufreq-info
• lsblk
• hdparm -tT /dev/sda
• ethtool --offload eth0 rx on tx on sg on tso on gso on gro on
• apt install armbian-config
• ls /sys/class/leds/
• cat /etc/default/cpufrequtils
• ls -al /sys/class/net
• udevadm info -q all -p /sys/class/net/wan
• cat /proc/version
• systemd --v
• cat /sys/devices/system/cpu/cpu1/cpufreq/stats/trans_table
• cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

From Armbian Ubuntu / Debian, be aware that:

manpage for systemd.netdev reads, in the part concerning the MACAddress= entry in the [NETDEV] section: If none is given, one is generated based on the interface name and the machine-id(5)

manpage for dbus-uuidgen, it says that the D-Bus machine-id should not be changed on a running machine or as they write: it will probably result in bad things happening. The machine-id should remain constant at least until next reboot.

• remove the SD card from the EspressoBin,
• mount it on a different Linux system
• delete /the/mounting/point/var/lib/dbus/machine-id
• generate a random new machine id using dbus-uuidgen –ensure=/the/mounting/point/var/lib/dbus/machine-id
• copy /the/mounting/point/var/lib/dbus/machine-id to /the/mounting/point/etc/machine-id
• put the SD card back to the EspressoBin
• use serial console to get the newly generated MAC address for br0
• use this MAC address in the dnsmasq configuration of my LeDe router

A few special projects to consider:

• TV headend (IPTV server)
• Syncthing (personal cloud)
• SoftEther VPN server (VPN server)
• Transmission (torrent server)
• ISPConfig (WEB & MAIL server)
• Openmediavault NAS (NAS server)
• PI hole (ad blocker)
• MiniDLNA (media sharing)

ust for the record: We have a SoC talking via RGMII to the onboard switch (currently with 1GbE but maybe 2.5GbE possible). We use DSA to tell the switch to not act as a switch on layer 2 anymore but separate downstream ports to get 3 individual interfaces just to bridge them again at the kernel layer above. Doing this at the DSA layer (telling the switch to be a dumb layer 2 switch accessible as eth0) might save CPU resources and result in better performance if I'm not wrong?

so it looks like the topaz switch needs to be talking to soc via SGMII instead of RGMII to achieve 2.5G.

..and I think i'm officially convinced that the max bandwidth between topaz switch and cpu is in fact 1gigabit... The connection is using a seperate RGMII lane. (eth0)

eth1 -- would be the interface capable of of SGMII, but the 3 fast lanes are occupied with USB, MiniPCI and SATA

• MTD: where the firmware and the u-boot environment are stored. The u-boot-tools package contains some utilities to read/modify the u-boot environment which is much more comfortable then in the interactive u-boot shell.
• pass the mtd partitioning information via the kernel command

Use HELIOS LanTest for file testing across network.

I/O Related Testing: "keep in mind that we've tested there 'advanced' stuff with mPCIe SATA controllers. On the onboard SATA port EspressoBin should in a single disk configuration easily exceed 500 MB/s (or in other words: Fast enough for any HDD imaginable) "

finding bottlenecks

beta sources

bootlin (formerly Free Electrons) - it was confirmed that support for the Marvell 3720 security engine is available in the crypto tree of 4.16-rc1 and that some known bugs will be fixed until the final release of 4.16.

I had a quick look over the diff for 4.16-rc1 and it looks like there's progress on support for DVFS too

These problems seem to arise (after some time) if your board is powered simultaneously by two sources with different GND potentials (check DC and AC). In this case your board will be exposed to severe electrical and thermal strain causing hardware issues after some time. It can be avoided if you access the serial console using a laptop that is not connected to a power supply itself (see usb/main power ).

IO Crest SI-MPE15047 4 Port Serial Mini PCIe Controller Card (RS-232) - could be used as console server.

IO Crest 4 Port SATA III Mini Pci-E Controller Card Components Other SI-MPE40125

M.2 form factor

Inside Secure, a SafeXcel EIP-97/197 cryptographic engine designed by Inside Secure, installed with 'modprobe crypto_safexcel'. More info at in a forum posting. The Kernel has some docs. Intelectual property sheet for EIP-97 - References IPsec, MACsec, SRTP, SSL, TLS, and DTLS.

From Reverse-engineering the ESPRESSObin’s GPIO pins:

• Symmetry Electronics has Powered Equipment POE modules by SilverTel

• Vitesse VSC73xx DSA router driver for a now obsolete Enhanced 5 + 1-Port Integrated Gigabit Ethernet Switch with Transceivers.
• swconfig from OpenWrt, goal of the switch configuration API is to provide a common basis to build re-usable and extensible switch drivers, developed in parallel with the kernel's own:
• Distributed Switch Architecture
• LWN: The rise of Linux-based networking hardware

• SAMA5D3 Xplained is a fast prototyping and evaluation platform for microprocessor-based design based upon the SAMA5D36 processor. It has a 100mbps and a 1gbps interface. Linux4SAM supplies the tooling to support the card. Linux mainline 4.9 with specific contributions. Features KSZ9031 and KSZ8081 PHYs with connectors. Could maybe replace with something like KSZ9893R 3 port Gigabit Switch or KSZ9896 6 port Gigabit Switch or KSZ9897S 7 port Gigabit Switch? A 100 <-> 1000 Software Bridge will use 95% cpu.
• Cyclone V SoC Multi-Port Ethernet Aggregator Board - NetLeap - NovTech's NetLeap, an Industry 4.0 Multi-Protocol Ethernet Ports Aggregator Platform, allows the development and integration of a variety of Ethernet protocols including PROFINET, EtherCAT, EtherNet/IP, Ethernet Powerlink, Modbus TCP, SERCOS III and more. This solution is preproduction ready. A total of six 1G/100/10 Ethernet ports are present. Two are connected to the HPS (The ARM* Cortes-A9 core of the Cyclone® V SoC) and four are connected to the FPGA fabric. With its six ports, the NetLeapâ„¢ allows different protocols to reside on the same platform and can be used as a protocol bridge, a switch, or a router. The kit comes with a templated project example that allows the board to boot to Linux and have all six ports work as a standard Ethernet.
• Networking Products - SG-1000 microFirewall Security Appliance
• Newport GW6400 - High Performance Single Board Computers for Networking with 4x Mini-PCIe Sockets, 5x Gigabit Ethernet Ports, and USB 2.0/3.0
• NFV PicoPod s a Cluster of Six MACCHIATOBin Networking Boards for OPNFV, ODP, DPDK and OPF
• SolidRun ClearFog Base is a $90 Router/Networking Board with USB 3.0, M.2, mSATA, and Gigabit Ethernet Support
• Orange Pi R1 - dual 10/100 ports for $14
• EspressoBin offers Marvell’s dual-core, Cortex-A53 Armada 3720 SoC, plus 2x GbE, 1x WAN, SATA, and mini-PCIe. GlobalScale shopping cart. Hack-A-Day leads to Building my ideal router for $50 (which talks about wireless, netflow, and security). ArchLinux|ARM has an install page. reddit says " 4.17 in particular ? It has hardware offload for the Topaz switch and the nic chip in the Espressobin which might reduce cpu usage", using a four drive setup as an example in the article. armbian has various add-on cards for mPCI and USB. arch linux ARM setup.
• Sinovoip’s “Banana Pi BPI-R2” router SBC gives you 5x GbE, WiFi, BT, 2GB RAM, 8GB eMMC, SATA, and mini-PCIe, plus a quad-core -A7 MediaTek MT7623N. More info on the gitbooks and the wiki and forum. Among other sites, can be ordered from AliExpress. Other info at armbian. Lots of links at end of BPI-R2. aluminum cases. BPI-4G LTE module.
• SolidRun’s “Marvell MacchiatoBIN” is a $349, Mini-ITX networking SBC that runs Linux 4.4 on Marvell’s quad -A72 Armada 8040, and supports ODP, OFP, and NFV. Main Site. I just wish Marvell would be more forthcoming on documentation on their chipsets rather than hiding behind NDA all the time. Pico MacchiatoBIN - with case, power supply, fan. Provided link to Marvell Prestar DX Switches which have VxLAN support. Suggests it works with OpenFlow 1.4 (open vswitch enabled?). arch linux ARM setup.
• EPIC-KBS9 from Aaeon is an SBC with 6th or 7th Gen Core S-series chips, 4x GbE ports, up to 32GB DDR3, and mini-PCIe and PCIe x4 expansion.
• minnowboard two port boards in the $200 range.
• PC Engines - APU2 board with four ports and wifi/lte. And in the $100 - $200 price range.

Other boards:

• BeagleBone Blue - mucho I/O: Motor control: 8 6V servo out, 4 bidirectional DC motor out, 4 quadrature encoder in; Sensors: 9 axis IMU (accels, gyros, magnetometer), barometer, thermometer
• FireFly - interesting add-ons like cameras, ASTRA Pro Structured Light Camera, binocular camera, capacitive touch screens, remote controls, ..
• ODroid
• ZedBoard: community-based site is dedicated to helping you jump-start your design with the Xilinx Zynq®-7000 All Programmable SoCs and UltraScale+ MPSoCs

Canada vendors:

• Mouser Electronics
• Newark element14
• Digi-Key
• Lees Electronic - Vancouver - electronic and mechanical
• Buy a PI - various SBC's
• CorpShadow BizStore - selling PCEngines network boards, among other things.

Embedded systems reviews:

• Linux Gizmos
• CNXSoft – Embedded Systems News

Embedded Linux Wiki

search engines for electronic parts

• Octopart
• digipart

Evolution to 'build your own"

• mikroETH 100
• Microchip's Ethernet Portfolio
• KSZ9031 Gigabit Ethernet Transceiver with Power Saving Feature
• AN1120: Ethernet Theory of Operation
• Segger physical connectivity example
• Microchip High Throughput Ethernet Interface Solutions
• 32 bit ARM with 2xGE
• 1G Ethernet PHYs by Microsemi (some have MacSec capability

Other linux SoC

• Linux for Amlogic Meson
• BORA Xpress XILINX Zynq CPU module

AVB

• Audio Visual Bridging - AKA IEEE 1588 / 802.1AS Time Stamping
• KSZ9567 7-Port Gigabit Ethernet Switch with AVB, IEEE 1588, SGMII/RGMII/MII/RMII
• KSZ9477 7-Port Gigabit Ethernet Switch with Ring Redundancy, AVB, IEEE1588, SGMII/RGMII/MII/RMII

• Awesome Electronics - github curated links

2018/10/20

• PC Engines - an international dealer network, boards with 1, 2, 3, 4 ethernet ports
• board db - SoC search engine

2018/12/24 - not networking, but clustering - need to find a multiport switch

• Pine64

• MicroChip Ethernet Switches - KSZ series with IEEE 1588v2 PTP
• Silicon Labs PoE+ Devices
• Micro Semi Ethernet Solutions as well as PoE

2019/06/25 - Protection Systems

• OPNsense - 'BSD solution, fork of pfsense - A good firewall for a small network - installation notes.

2020/01/10 - HoneyComb LX2K - is a robust embedded Mini ITX platform designed for the COM Express type 7 form factor, features an array of 4 x 10GbE SFP+ connectors and 1 x 1GbE RJ45 port, based on NXP’s outstanding 16 core LX2160A Arm Cortex A72 (2GHz) offering up to 64GB DDR4 (dual channel) and up to 40GbE. Debian bug #948576: linux: please enable support for the layerscape SoCs and the Honeycomb workstation board

A place to keep links for embedded systems components, parts, robotics, ...

• Olimex - European company with the OLinuXino brand, and can be found through various distribution channels.
• seeed studio - IoT hardware enabler
• AdaFruit - to create the best place online for learning electronics and making the best designed products for makers of all ages and skill levels
• Think Penguin - not necessarily embedded, but they do provide Linux based computers and laptops, linked from TCP small queues and WiFi aggregation — a war story.
• Digilent embedded systems of various styles, fpga, ...
• 2021/05/23 robot shop - checkout the ydlidar stuff

• Scientist and Engineer's Guide to Digital Signal Processing by Steven W. Smith, Ph.D. - an online book

The article DON'T USE ARDUINO (FOR PROFESSIONAL WORK) provides some thoughts on reasons not to use Arduino, including concepts on troubleshooting, licensing, and power utilization. All good reasons.

And the author did provide a couple of alternatives:

• Linux Gizmos: an unending supply of announcements
• arm mbed
• Lets Get Board talks about differences between three versions of Cortex architectures.
• STM32: I've heard about this a number of times
• Arduino's own list alternatives

I have been looking at alternatives for entry-access mechanisms. Some things to be looked into include:

NFC (Near Field Communications)
• Arduino NFC Shield features a transceiver module, PN532, which handles wireless communication at 13.56MHz, this means that you can read and write a 13.56MHz tag with this shield or implement point to point (P2P) data exchange between the shield and a smart phone. There is an NFC Library using PN532 to read/write card and communicate with android.
• Tutorial for NFC Shield and NFC Module from ElecFreaks.

Also similar to the topic is the controls behind the scenes. It is possibly to turn an Arduino into a PLC, complete with PLC style enclosures and PLC style software:

• CONTROLLINO was the first ARDUINO compatible software open-soure PLC (programmable logic controller) and is the market leader in its field. Programming software for the solution.
• Industrial Shields
• industruino prototyping kit
• Hartmut Wendt DIN rail enclosure: ArduiBox Open for Arduino Uno, 101, Zero
• plcLib: PLC Software for the Arduino

ModBerry, a Raspberry Pi based controller, but being Linux based, not quite so deterministic as an Arduino based product.

Automation Direct: not really open source, but lots of automation stuff.

Other interesting bits:

• LoRa mini long distance wireless rx/tx. Along with this low power scenario, there are solar cells and Lithium Ion Polymer batteries, and charger.
• DMX Shields. Some additional info on DMX512 as an Arduino shield.
• DMX 512 Opto Isolated Arduino shield. Lots of other interesting projects at this site.
• MegaMoto Motor Control Shield for Arduino -- 30A of current at up to 28V in two half bridge or one full bridge.
• Grid-Eye 8x8 IR Array

2017/10/26: LORA Chat Box from Hack-A-Day - Decentralised LoRa based Chat firmware for ESP32 boards by Heltec (and clones)