The trigger to start this project was remarking, for the umpteenth time in the morning, that the door had been unlocked again all night.
Replacing the mechanical locks on the 4 doors by electric locks was out of the question, too expensive and the need for electric cables that were not present.

So, how to detect if a mechanical lock is closed?

The internet is an incredible source of ideas:
https://community.home-assistant.io/t/how-i-made-my-dumb-locks-a-little-smarter/55174
https://community.home-assistant.io/t/i-made-a-simple-lock-sensor-with-xiaomi-door-sensor-some-battery-holders-and-a-soldering-iron/49445
With this idea, let the bolt close a contact, I could use the standard window/door sensor node!
So I made my version by using springs I found in my junk bin mounted on a piece of wood, namely the wooden stick of an ice cream
My first prototype was working, but not really a piece of art

Remember to always drill holes because the wood of the stick splits very easily.

I did use battery springs for my other nodes, they are stronger and easier to use.

The battery-based windows/door sensor node : hardware

I had never built a battery based node before, so as a first step, I did read the site article on the MySensors site: https://www.mysensors.org/build/battery

Luckily, I already had Pro Mini's and enough RFM69HW radios in stock.
Today I know that I did probably the wrong choice by using the Pro Mini’s. They are good in low consumption, but a bare bone 328P used like in this topic https://forum.mysensors.org/topic/2067/my-slim-2aa-battery-node is still better...
But we will see how far these Pro Mini’s will take us on 2x AA batteries!

My first node was based on the idea to use the same enclosure as in the above topic. In Belgium these cable ducts are known under the name Legrand and I had a still a piece of more then 1 meter lying around, a surplus from the renovations.

Because I used a Pro Mini and not a bare bone 328P, I was obliged to use 2 covers of the cable duct instead of a cover and base. The base of the cable duct was not broad enough for the Pro Mini.

With the hardware tricks of the MySensor battery node site article on the Pro Mini, I could obtain a current consumption of 133µA in deep sleep (Modified Pro Mini, RFM69HW and the open contact).

To minimize the current with a closed contact, I did not use the internal pull-up resistor of the 329P (internal pullup resistor value around 30KOhm), but an external 1M ohm resistor. With closed contact and deep sleep, I have now around 136µA.

The battery-based windows/door sensor node : software
Besides the hardware modifications done at the Pro Mini, you can also do software modifications to save power consumption.
In the same topic https://forum.mysensors.org/topic/2067/my-slim-2aa-battery-node, the author @m26872 mentioned the use of a new bootloader with a 1MHz internal clock and a BOD (cpu brown out) disabled.

Today (2020-12-28) we can use the github project MiniCore https://github.com/MCUdude/MiniCore to program our Arduino Pro Mini with the new bootloader. See the readme of the project MiniCore on Github. It explains everything: the theory, the installation and the Getting Started.

After installing MiniCore, I used following configuration:

• board : ATmega328
• clock : internal 1 MHz
• BOD : BOD 1.8V
• EEPROM : EEPROM retained
• Variant : 328P / 328PA
• Bootloader : Yes (UART0)

Remark 1
I did not disable completely the BOD. Why? I did read on forums that the processor could write garbage into the memory when below 1.8V, so for safety’s sake, I did set it to 1.8V.
Remark 2
There are reports that using the Arduino Pro Mini at internal 1Mhz gives sometimes problems with the MySensors library. It was not clear to me if it was with the 1.x version of MySensors or the 2.x version, so I did take my chance and used 1MHz with the 2.3 version of MySensors. Till now, no problems!

You must program the bootloader with an ISP. I used my ‘Arduino as ISP’. See https://forum.mysensors.org/topic/11444/using-an-arduino-uno-as-isp-for-programming-5v-and-3-3v-boards-without-soldering-the-needed-connections

Remark
If your pro mini is already connected to the RFM69HW radio, D11, D12 and D13 are used as MISO, MOSI and SCK for the radio.
These pins are also used to program the bootloader.
This will affect each other. The ISP programmer will not be able to detect the device ID and will fail. You must disconnect these 3 lines from the radio module, the time to (re)program the bootloader.

You can find the used sketch at https://github.com/ericvb/MySensorsArduinoSketches/tree/master/sketches/ArduinoProMiniLockDoorBatterySensorWithEncryptionGithub

The battery-based windows/door sensor node : 3D printing enclosure

Because I had to use the cover of the cable duct as base for the Pro Mini, I decided to design a case with approximately the same dimensions.
The dimensions were dictated by the available space in the PVC door frame, the dimensions of the Pro Mini, the RFM69HW, the 2 AA batteries and the minimum possible printed thickness still solid by my 3D printer:

• Length : 200mm
• Width: 20mm
• Height: 17mm

You can find the design (open source FreeCAD) and STL files at: https://www.thingiverse.com/thing:4659402
The last months the thingiverse website has many problems, designs are not visible, 404 messages, etc.
Post a note if you don't find the 'thing'

The sensor is fastened with Velcro strips to prevent damage to the door caused by using fixing screws.

References

Via following links, you can find more information about minimal power consumption, bootloaders, etc.
Low power Pro Mini

https://www.mysensors.org/build/battery
https://forum.mysensors.org/topic/2067/my-slim-2aa-battery-node
https://forum.mysensors.org/topic/486/my-2aa-battery-sensor
https://iot-playground.com/blog/2-uncategorised/10-low-power-door-window-sensor
https://iot-playground.com/blog/2-uncategorised/9-arduino-low-power-sensor
http://www.gammon.com.au/power
https://www.iot-experiments.com/arduino-pro-mini-power-consumption/
https://forum.pimatic.org/topic/383/tips-battery-powered-sensors/

Battery consumption

https://forum.mysensors.org/topic/10426/ds18b20-on-2xaaa-battery
https://andreasrohner.at/posts/Electronics/How-to-modify-an-Arduino-Pro-Mini-clone-for-low-power-consumption/

Specific commercial hardware

https://www.canique.com (power efficient board with RFM69HW)
https://www.tindie.com/stores/easysensors/
https://www.tindie.com/products/vysocan/rfm69-radio-node-mini/

Use of bootloaders

https://www.iot-experiments.com/arduino-pro-mini-1mhz-1-8v/
https://forum.mysensors.org/topic/7296/how-to-burn-fuses-so-that-pro-mini-3-3v-would-go-down-to-1-8v-solved/17
https://forum.mysensors.org/topic/3018/tutorial-how-to-burn-1mhz-8mhz-bootloader-using-arduino-ide-1-6-5-r5
https://forum.mysensors.org/topic/3657/mymultisensors/144
https://forum.mysensors.org/topic/5478/how-to-get-longest-battery-life/42

This post is a try to order my thoughts about the mysensors implementation possibilities for signing and encryption.

I thought that it could be of some help for other people, who are new, like me, to mysensors and want to start using it.
This is written with in mind the current version 2.3.1 of the mysensors libary and 2 Arduinos Uno's R3 as hardware. Be aware that this can change in the future as the library will continue to evolve!

Please, if you find any mistakes, don't hesitate to point them out to me so I can correct this post.

First some (condensed) theory found in the docs and on this forum.

Two different things:

• Signing messages : this makes that the receiver is sure that the received message is really from the transmitter. The message can't be changed by somebody during the transmission of the message. This is done by the MySensors message protocol.
  More detailed explication can be found on: https://www.mysensors.org/apidocs/group__MySigninggrpPub.html#MySigninggrpencryption

• Encryption of the messages: is done on the level of the used radio itself. For RFM69HW for example, it is done by the hardware itself of the radio. It is independent from the MySensors message protocol implementation.

A. Signing of the messages

Three possibilities: 2 based on software and one based on extra external hardware. The latest I can't test because I have no Atmel ATSHA204 chips lying around...

• First option, software backed by using only a password : weaker security, but simple to activate.

  MY_SIGNING_SIMPLE_PASSWORD: this keyword enables security only on the level signing
  If the provided password is shorter than the size of the HMAC key, it will be null-padded to accommodate the key size in question. A 32 character password is the maximum length. Any password longer than that will be truncated.

• Second option, sofware backed

  MY_SIGNING_SOFT: this keyword enables security only on the level signing

  If MY_SIGNING_SIMPLE_PASSWD is used a personalisation must not be done.
  If not used, a personalization must be done, the values are stored in EEPROM.(see: https://www.mysensors.org/apidocs-beta/group__MySigninggrpPub.html#personalization). See also further on.

• Third option, hardware backed via the Atmel ATSHA204 chip

  MY_SIGNING_ATSHA204: this keyword enables security only on the level signing

  If MY_SIGNING_SIMPLE_PASSWD is used a personalisation must not be done.
  If not used, a personalization must be done, the values are written to the Atmel ATSHA204 ship. It is irreversible!! (see https://www.mysensors.org/apidocs-beta/group__MySigninggrpPub.html#personalization)

B. Encryption of the radio transport level

Only possible for the supported radios (RF24, RFM69, NRF5, RFM95 at current library version 2.3.1)(https://www.mysensors.org/apidocs-beta/group__EncryptionSettingGrpPub.html)
The RFM69 radio does support hardware encryption of the communication using AES (Advanced Encryption Standard).

• MY_ENCRYPTION_SIMPLE_PASSWORD: this keyword enables encryption on all radio communications of the radio types that supports it and uses provided password as key.
  If the provided password is shorter than the size of the AES key, it will be null-padded to accommodate the key size in question. A 16 character password is the maximum length. Any password longer than that will be truncated.
  example : #define MY_ENCRYPTION_SIMPLE_PASSWD "MyInsecurePassword"

If you are already using the first option of signing messages (MY_SIGNING_SIMPLE_PASSWORD), you can replace it by following keyword:

• MY_SECURITY_SIMPLE_PASSWORD: this keyword enables security on the level signing and encryption (only usable on Arduino. On the Raspberry PI use the other two simple options)

My practical tests

• a sensor based on an Arduino Uno with the sketch UltraSonic_sensor from the website adapted for the RFM69HW radio
• a gateway based on an Arduino, a W5100 ethernet shield for the Uno and a radio RFM69HW (see https://forum.mysensors.org/topic/10358/solved-mqtt-gateway-based-on-arduino-uno-uno-compatible-w5100-ethernet-shield-rfm69hw-radio)

1. Added in the two sketches: only encryption

#define MY_ENCRYPTION_SIMPLE_PASSWORD "my16characterpassword"

Result : it works

1. Added in the two sketches: encryption and simple signing

#define MY_ENCRYPTION_SIMPLE_PASSWORD "my16characterpassword"
#define MY_SIGNING_SIMPLE_PASSWORD "my32characterpassword"

Result : warning when downloading the code into the gateway: "Low memory available, stability problems may occur."
It doesn't work!

1. Added in the two sketches: encryption and simple signing

#define MY_ENCRYPTION_SIMPLE_PASSWORD "my16characterpassword"
#define MY_SIGNING_SIMPLE_PASSWORD "my16characterpassword"

Result : warning when downloading the code into the gateway: "Low memory available, stability problems may occur."
It doesn't work!

1. Added in the two sketches: the shortcut define for the Arduino platform

#define MY_SECURITY_SIMPLE_PASSWORD "my16characterpassword"

Result : it works

1. Added in the two sketches: the shortcut define for the Arduino platform

#define MY_SECURITY_SIMPLE_PASSWORD "my32characterpassword"

Result : it works

Is this shortcut define specially done for the Arduino platform to avoid the low memory condition?

1. Added in the two sketches : encryption and soft signing with simple password personalization

//enable radio communication encryption
#define MY_ENCRYPTION_SIMPLE_PASSWD "my16characterpassword"
#define MY_SIGNING_SIMPLE_PASSWD "my32characterpassword"
#define MY_SIGNING_SOFT
#define MY_SIGNING_REQUEST_SIGNATURES
#define MY_SIGNING_SOFT_RANDOMSEED_PIN A0

Result : warning when downloading the code into the gateway: "Low memory available, stability problems may occur."
It doesn't work. The signing is failing.

1. Added in the two sketches : encryption and soft signing with personalization
   First we will personalize each arduino (the sensor and the gateway)

• open the SecurityPersonalizer.ino file via the Arduino IDE menu File, Examples, Mysensors, SecurityPersonalizer
• uncomment the define GENERATE_KEYS_SOFT
• upload the sketch to your Arduino
• open the serial monitor
• here you will find your generated keys HMAC and AES keys
• copy the entries under the 'Key copy section' into the SecurityPersonalizer.ino file
• comment again the define GENERATE_KEYS_SOFT

The following 3 steps must be done on each node where you want to use soft signing

• uncomment the define PERSONALIZE_SOFT
• upload the sketch again to your Arduino
• in the serial monitor output you will find now that the keys are written to the EEPROM (see EEPROM section)

The following 5 steps must also be done on each node where you want to use whitelisting

• if you want to use whitelisting and your device does not provide a unique device ID, you have to generate a unique serial and store it in EEPROM (my arduino uno does not provide a unique device ID, so I must run the sketch)

• comment the define PERSONALIZE_SOFT

• uncomment the define PERSONALIZE_SOFT_RANDOM_SERIAL

• upload the sketch to your Arduino

• in the serial monitor output you will find now a generated serial unique device ID. This unique serial ID must be copied somewhere on a safe place. You must later on copy this key in the whitelisting define of your gateway and nodes sketches.

• Take now your sketches and add the following defines

//enable radio communication encryption
#define MY_ENCRYPTION_SIMPLE_PASSWD "my16characterpassword"
//enable soft signing
#define MY_SIGNING_SOFT
#define MY_SIGNING_REQUEST_SIGNATURES
#define MY_SIGNING_SOFT_RANDOMSEED_PIN A0
#define MY_SIGNING_NODE_WHITELISTING {{.nodeId = 0,.serial = {0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99}},{.nodeId = 1,.serial = {0x99,0x88,0x77,0x66,0x55,0x44,0x33,0x22,0x11}}}

The MQTT gateway has always nodeid = 0 and my sensor has nodeid = 1 (the sensors must have a fixed set nodeid because in MQTT mode, the controller (like HomeAssistant) can't assign node ids).
The serials given above are fake numbers, use the ones from your sketch!

Result : warning when downloading the code into the gateway: "Low memory available, stability problems may occur."
It doesn't work!

So I think that in my case, with an Arduino Uno as MQTT gateway, only the simple signing and encryption is possible.
Maybe the hardware backed signing, but I can't test this at this moment. (see my other question : https://forum.mysensors.org/topic/10370/is-there-still-a-breakout-board-for-the-atmel-atsha204a-chip)

Apparently this day is my lucky day

@scalz , you did me think with your comment about the samd21 board not triggering the irq.

So I looked up where the pin layouts of all these 'arduino compatible' boards are defined.
My used board is a RobotDyn Samd21 M0 board and they claim compatible with a Arduino M0 and I did use the Arduino SAMD boards (32-bits ARM Cortex-M0+) by Arduino version 1.8.3.
The code you find at: https://github.com/arduino/ArduinoCore-samd
With some help of the google doctor, I did find that the pin layouts are defined in the Variants.cpp file in
https://github.com/arduino/ArduinoCore-samd/blob/master/variants/arduino_mzero/variant.cpp
(I'm using the Arduino M0 entry when selecting my board)
In this file

/*
 *
 * + Pin number +  ZERO Board pin  |  PIN   | Label/Name      | Comments (* is for default peripheral in use)
 * +------------+------------------+--------+-----------------+------------------------------
 * |            | Digital Low      |        |                 |
 * +------------+------------------+--------+-----------------+------------------------------
 * | 0          | 0 -> RX          |  PA11  |                 | EIC/EXTINT[11] ADC/AIN[19] PTC/X[3] *SERCOM0/PAD[3] SERCOM2/PAD[3] TCC1/WO[1] TCC0/WO[3]
 * | 1          | 1 <- TX          |  PA10  |                 | EIC/EXTINT[10] ADC/AIN[18] PTC/X[2] *SERCOM0/PAD[2] TCC1/WO[0] TCC0/WO[2]
 * | 2          | ~2               |  PA08  |                 | EIC/NMI ADC/AIN[16] PTC/X[0] SERCOM0/PAD[0] SERCOM2/PAD[0] *TCC0/WO[0] TCC1/WO[2]
 * | 3          | ~3               |  PA09  |                 | EIC/EXTINT[9] ADC/AIN[17] PTC/X[1] SERCOM0/PAD[1] SERCOM2/PAD[1] *TCC0/WO[1] TCC1/WO[3]
 * | 4          | ~4               |  PA14  |                 | EIC/EXTINT[14] SERCOM2/PAD[2] SERCOM4/PAD[2] TC3/WO[0] *TCC0/WO[4]
 * | 5          | ~5               |  PA15  |                 | EIC/EXTINT[15] SERCOM2/PAD[3] SERCOM4/PAD[3] TC3/WO[1] *TCC0/WO[5]
 * | 6          | ~6               |  PA20  |                 | EIC/EXTINT[4] PTC/X[8] SERCOM5/PAD[2] SERCOM3/PAD[2] TC7/WO[0] *TCC0/WO[6]
 * | 7          | ~7               |  PA21  |                 | EIC/EXTINT[5] PTC/X[9] SERCOM5/PAD[3] SERCOM3/PAD[3] TC7/WO[1] *TCC0/WO[7]
 * +------------+------------------+--------+-----------------+------------------------------
 * |            | Digital High     |        |                 |
 * +------------+------------------+--------+-----------------+------------------------------
 * | 8          | ~8               |  PA06  |                 | EIC/EXTINT[6] PTC/Y[4] ADC/AIN[6] AC/AIN[2] SERCOM0/PAD[2] *TCC1/WO[0]
 * | 9          | ~9               |  PA07  |                 | EIC/EXTINT[7] PTC/Y[5] DC/AIN[7] AC/AIN[3] SERCOM0/PAD[3] *TCC1/WO[1]
 * | 10         | ~10              |  PA18  |                 | EIC/EXTINT[2] PTC/X[6] SERCOM1/PAD[2] SERCOM3/PAD[2] *TC3/WO[0] TCC0/WO[2]
 * | 11         | ~11              |  PA16  |                 | EIC/EXTINT[0] PTC/X[4] SERCOM1/PAD[0] SERCOM3/PAD[0] *TCC2/WO[0] TCC0/WO[6]
 * | 12         | ~12              |  PA19  |                 | EIC/EXTINT[3] PTC/X[7] SERCOM1/PAD[3] SERCOM3/PAD[3] *TC3/WO[1] TCC0/WO[3]
 * | 13         | ~13              |  PA17  | LED             | EIC/EXTINT[1] PTC/X[5] SERCOM1/PAD[1] SERCOM3/PAD[1] *TCC2/WO[1] TCC0/WO[7]
 * | 14         | GND              |        |                 |
 * | 15         | AREF             |  PA03  |                 | *DAC/VREFP PTC/Y[1]
 * | 16         | SDA              |  PA22  |                 | EIC/EXTINT[6] PTC/X[10] *SERCOM3/PAD[0] SERCOM5/PAD[0] TC4/WO[0] TCC0/WO[4]
 * | 17         | SCL              |  PA23  |                 | EIC/EXTINT[7] PTC/X[11] *SERCOM3/PAD[1] SERCOM5/PAD[1] TC4/WO[1] TCC0/WO[5]

This is the defined pin mapping for a Arduino mZero. (I was using D2 as IRQ for the RFM69)

* | 2          | ~2               |  PA08  |

But on the pin layout of the RobotDyn board I saw:

* | 2          | ~2               |  PA14  |

On the RobotDyn the pin PA08 is mapped on the D4 arduino pin and not the D2 pin!
With the pins D2/D4, RobotDyn is following here the Arduino Zero layout and NOT the Arduino mZero layout!

So, I verified the other mappings and found that following pins are different mapped on the Arduino mZero:

 * | 2          | ~2               |  PA08  | 
 
 * | 4          | ~4               |  PA14  | 

On the RobotDyn Samd21M0

 * | 2          | ~2               |  PA14  | 

 * | 4          | ~4               |  PA08  | 

So I changed the IRQ (DIO0) from the RF69 to the port D8 (PA06) and bingo it started to work (did choose randomly D8)

I saw also a difference in the SPI mapping
mZero

 * | 18         | 1                |  PA12  | MISO 

RobotDyn samd21 m0

 * |  not defined on their pin layout doc       | 1                |  PB12  | MISO 

But it is working, so maybe an error on RobotDyn's documentation?

So if I resume the thing:
The RobotDyn SAMD21 M0 board is claimed compatible with the Arduino M0 (mZero). In the IDE you must also select the Arduino M0. (selecting Arduino/Genuino Zero xxx will not work)
But the RobotDyn used layout is compatible with the Arduino Zero, so pin D2 and D4 are reversed, making the code of the board Arduino M0 not working if you choose to use these pins in your design.

So now we can continue to build our gateway, my originally goal.
Edit : my MQTT gateway with the RobotDyn Samd21 M0 board, a W5500 ethernet module and a radio RFM69HW is up and running

Thanks for all comments that guided me to the solution

Nobody has never build a gateway based on an Arduino Uno, a W5100 shield and a RFM69HW?

So I will answer my own questions
I did take my chance and choose to build first a gateway version using the hardware SPI bus (no soft spi) and I was lucky, it worked directly! So no need to try the soft-spi version.

Because I did already build previously a sensor (https://www.mysensors.org/build/distance), I had all hardware already ready to be used.

So what is the used hardware?

• one standard Arduino Uno R3 (guine or chinese clone, DON'T BUY WAVGAT arduino uno types, they require specific hardware drivers in the Arduino IDE and this manufacturer doesn't update his own old drivers!!)(https://www.aliexpress.com/item/1pcs-Smart-Electronics-high-quality-UNO-R3-MEGA328P-CH340G-Compatible-NO-USB-CABLE-for-arduino/32830661533.html)
• one RFM69HW, version 868MHz (check what you can use at your country!)(https://www.aliexpress.com/item/Free-Shipping-RFM69HW-868Mhz-Transceiver-Module-High-Integrated-HopeRF-Wireless-868S2-Module-SPI-1-8-3/32810316806.html)
• one helical antenna (https://www.aliexpress.com/item/10PCS-868MHz-Helical-Antenna-2-15dBi-13mm-Stable-for-Remote-Contorl/32668155368.html)
• one W5100 shield pin compatible with an Arduino Uno (https://www.aliexpress.com/item/Free-Shipping-UNO-Shield-Ethernet-Shield-W5100-R3-UNO-Mega-2560-1280-328-UNR-R3-only/32502588687.html)
• one proto shield to build the RFM69HW radio on top of the W5100 shield (https://www.aliexpress.com/item/Standard-Proto-Screw-Shield-Board-For-Arduino-Compatible-Improved-version-support-A6-A7-Diy-Kit-Electronic/32832054800.html)
• one logic channel convertor between Arduino 5V and RFM69HW radio 3.3V (https://www.aliexpress.com/item/3-3V-5V-TXS0108E-8-Channel-Logic-Level-Bi-directional-Converter-Module-TXB0108-Mutual-Convert-Module/32916020205.html)

The hardware is wired following next schematic:

Connecting the RFM69HW hardware was somewhat tricky. The used pin headers on the RFM69HW are not following the standard spaced 2.54mm pin headers like on the Arduino print. I did not have a converter plate, so I soldered some hard wire into the RFM69HW pins and bend them into the pin holes from the protoboard. See photo.

So what about the software:

• Arduino IDE version 1.8.9
• MySensors library 2.3.1

I did take as base the sketch found on the website https://www.mysensors.org/build/mqtt_gateway or https://github.com/mysensors/MySensors/blob/master/examples/GatewayW5100MQTTClient/GatewayW5100MQTTClient.ino

Important is to configure the specific RFM69 defines
#define MY_RADIO_RFM69
#define MY_RFM69_FREQUENCY RFM69_868MHZ // Set your frequency here
#define MY_IS_RFM69HW // Omit if your RFM is not "H"
#define MY_RFM69_NEW_DRIVER

When the W5100 Arduino shield is connected we have to move SS (slave select) pin for the RFM69 radio because the shield is using the default D10
#define MY_RFM69_CS_PIN 6

/*
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2019 Sensnology AB
 * Full contributor list: https://github.com/mysensors/MySensors/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0 - Henrik Ekblad
 * Version 1.1 - Eric Van Bocxlaer
 *
 * DESCRIPTION
 * The W5100 MQTT gateway sends radio network (or locally attached sensors) data to your MQTT broker.
 * The node also listens to MY_MQTT_TOPIC_PREFIX and sends out those messages to the radio network
 *
 * LED purposes:
 * - To use the feature, uncomment WITH_LEDS_BLINKING in MyConfig.h
 * - RX (green) - blink fast on radio message received. In inclusion mode will blink fast only on presentation received
 * - TX (yellow) - blink fast on radio message transmitted. In inclusion mode will blink slowly
 * - ERR (red) - fast blink on error during transmission error or receive crc error
 *
 * See http://www.mysensors.org/build/esp8266_gateway for wiring instructions.
 * nRF24L01+  ESP8266
 * VCC        VCC
 * CE         GPIO4
 * CSN/CS     GPIO15
 * SCK        GPIO14
 * MISO       GPIO12
 * MOSI       GPIO13
 *
 * Not all ESP8266 modules have all pins available on their external interface.
 * This code has been tested on an ESP-12 module.
 * The ESP8266 requires a certain pin configuration to download code, and another one to run code:
 * - Connect REST (reset) via 10K pullup resistor to VCC, and via switch to GND ('reset switch')
 * - Connect GPIO15 via 10K pulldown resistor to GND
 * - Connect CH_PD via 10K resistor to VCC
 * - Connect GPIO2 via 10K resistor to VCC
 * - Connect GPIO0 via 10K resistor to VCC, and via switch to GND ('bootload switch')
 *
  * Inclusion mode button:
 * - Connect GPIO5 via switch to GND ('inclusion switch')
 *
 * Hardware SHA204 signing is currently not supported!
 *
 * Make sure to fill in your ssid and WiFi password below for ssid & pass.
 * 
 * ***************************************************************************************************************
 * Connection with RFM69HW and EthernetShieldW5100 through the SPI bus (Serial Peripheral Interface)
 * On this bus we can have only one master (= the Arduino Uno) and different slaves (= the W5100 and the RFM69HW).
 * The master can only talk to one slave each time!
 * 
 * RFM69HW    Uno R3    EthernetShieldW5100(autowired)
 * VCC 3.3V   VCC 3.3V  
 *            VCC 5.0V  VCC 5.0V
 * DIO0       D2/INT0
 * NSS        D6
 * SCK        D13/SCK   SCK (D13)
 * MISO       D12/MISO  MISO (D12)
 * MOSI       D11/MOSI  MOSI (D11)
 *            D4        SS (sd-card)
 *            D10/SS    SS (W5100)(Default in ethernet library: do not wire different with a no shield version!)
 *            
 * 
 * NSS/SS : Slave Select for SPI bus (the master selects with which slave he want to talk)
 * SCK : serial clock signal delivered by the master
 * MISO : Master Input Slave Output (arduino receives data from the slave)
 * MOSI : Master Output Slave Input (arduino sends data to the slave)
 */


// Enable debug prints to serial monitor
//#define MY_DEBUG
// Enable specific RFM69 debug prints to serial monitor
//#define MY_DEBUG_VERBOSE_RFM69

// Enables and select radio type (if attached)
//#define MY_RADIO_RF24
//#define MY_RADIO_RFM95
#define MY_RADIO_RFM69
#define MY_RFM69_FREQUENCY RFM69_868MHZ // Set your frequency here
#define MY_IS_RFM69HW // Omit if your RFM is not "H"
#define MY_RFM69_NEW_DRIVER

#define MY_GATEWAY_MQTT_CLIENT

// Set this node's subscribe and publish topic prefix
#define MY_MQTT_PUBLISH_TOPIC_PREFIX "mygateway1-out"
#define MY_MQTT_SUBSCRIBE_TOPIC_PREFIX "mygateway1-in"

// Set MQTT client id
#define MY_MQTT_CLIENT_ID "mysensors-1"

// Enable gateway ethernet module type : not needed here because MY_GATEWAY_MQTT_CLIENT defines already the use of W5100
//#define MY_GATEWAY_W5100
#define SD_SS_PIN (4)  // chip-select for SD card (normally unused, pull high!, see code!) 

// W5100 Ethernet module SPI enable (this setting is optional if using a shield/module that manages SPI_EN signal)
//#define MY_W5100_SPI_EN 4

// Enable Soft SPI for NRF radio (note different radio wiring is required)
// The W5100 ethernet module seems to have a hard time co-operate with
// radio on the same spi bus.
// Situation on 2019-05-04: with the new RFM69HW driver this is not true anymore for a radio RFM69!
//#if !defined(MY_W5100_SPI_EN) && !defined(ARDUINO_ARCH_SAMD)
//#define MY_SOFTSPI
//#define MY_SOFT_SPI_SCK_PIN 14
//#define MY_SOFT_SPI_MISO_PIN 16
//#define MY_SOFT_SPI_MOSI_PIN 15
//#endif

// When W5100 shield is connected we have to move SS (slave select) pin for the RFM69 radio because the shield
// is using the default D10
#define MY_RFM69_CS_PIN 6

// When W5100 is connected we have to move CE/CSN pins for NRF radio
//#ifndef MY_RF24_CE_PIN
//#define MY_RF24_CE_PIN 5
//#endif
//#ifndef MY_RF24_CS_PIN
//#define MY_RF24_CS_PIN 6
//#endif

// Enable these if your MQTT broker requires username/password
//#define MY_MQTT_USER "username"
//#define MY_MQTT_PASSWORD "password"

// Enable MY_IP_ADDRESS here if you want a static ip address (no DHCP)
//#define MY_IP_ADDRESS 192,168,178,87

// If using static ip you can define Gateway and Subnet address as well
//#define MY_IP_GATEWAY_ADDRESS 192,168,178,1
//#define MY_IP_SUBNET_ADDRESS 255,255,255,0

// MQTT broker ip address or url. Define one or the other.
//#define MY_CONTROLLER_URL_ADDRESS "m20.cloudmqtt.com"
#define MY_CONTROLLER_IP_ADDRESS 192, 168, 178, 68

// The MQTT broker port to to open
// With simple arduino uno's we can't use encrypted communication!
#define MY_PORT 1883

/*
// Enable inclusion mode
#define MY_INCLUSION_MODE_FEATURE
// Enable Inclusion mode button on gateway
//#define MY_INCLUSION_BUTTON_FEATURE
// Set inclusion mode duration (in seconds)
#define MY_INCLUSION_MODE_DURATION 60
// Digital pin used for inclusion mode button
//#define MY_INCLUSION_MODE_BUTTON_PIN  3

// Set blinking period
#define MY_DEFAULT_LED_BLINK_PERIOD 300

// Flash leds on rx/tx/err
// Uncomment to override default HW configurations
//#define MY_DEFAULT_ERR_LED_PIN 16  // Error led pin
//#define MY_DEFAULT_RX_LED_PIN  16  // Receive led pin
//#define MY_DEFAULT_TX_LED_PIN  16  // the PCB, on board LED
*/

#include <Ethernet.h>
#include <MySensors.h>

void before() {
    pinMode(SD_SS_PIN, OUTPUT);
    digitalWrite(SD_SS_PIN, HIGH); 
}

void setup()
{
    // Setup locally attached sensors
}

void presentation()
{
    // Present locally attached sensors here
}

void loop()
{
    // Send locally attached sensors data here
}

I hope that this will be helpful for some people trying to build something equivalent

@Snyfir another approach is to use another radio channel for your B network? That includes of course another gateway also...
An advantage is that you can stick with the standard MySensors library.
More information on : https://www.mysensors.org/download/sensor_api_20 : search channel

of course:
That’s why I want nodes of network (A) use only repeaters of network (A), and nodes of network (B) use repeaters of networks (A) and (B)
This will not be possible....

I needed a programmer quickly and because ordering one, would take too much time, I went the way of using an Arduino as ISP.

Programming another Uno, for example, is not difficult, you will find tutorials all over the net. The Uno's have soldered connectors, so you can use Dupont cables to do the needed connections.
If you have a Pro Mini 3.3V 8MHz, it is more complicated

• problem of 5V (UNO) versus 3.3V (Pro Mini)
  In some forum posts you can read that you can program a 3.3V one with 5V because the used chip is the same. Oké, that is maybe true, but what if you want to reprogram a Pro Mini with other connected 3.3V only hardware?
• how to connect the needed cables if you don't want to solder? (de-soldering a header is not one of my favorite activities, neither cleaning the solder holes )

One solution I found when Googling was this one: https://create.arduino.cc/projecthub/user3330224/programming-the-arduino-pro-mini-without-soldering-pins-7d033d from Ruben Zilzer.
I printed his 'clothes pins', but the problem are the used header pins. You must put solder on it to make sure that the connection is done. This must be done very accurately, because all pins must make good contact with the board. If you have one of them that has a lower soldering than the others, these others don't make contact and it doesn't work properly.
Imagine, to program a Pro Mini I used another Pro Mini, so in total 4 clothes pins.
I've done my best but I didn't manage to have each time a good contact between the 2 Arduino's.
Conclusion: a good idea, but unfortunately not reliable.

So, I searched the internet further on, but didn't find a reliable solution...

Until suddenly I remembered a very old, I think Elektor?, project, to build your own digital scope. Times when buying such a thing was outside everyone's personal budget.
Mini measuring clips were used to connect the scope to the DUT thing.

If I used these clips to do the connections?
I even found back this old project and could re-use the existing measure clips together with the flat cable, a profound stroke of luck

To solve the 5V to 3.3V problem, I did use the 8-Bit Bidirectional Voltage-Level Shifter TXS0108E. To make it configurable, I used jumpers.
See the following diagram

With the jumpers you select the needed voltage to program the target board.
Because I used an Uno as programmer, I can simple connect the Uno to the computer via the build in USB connector. No USB-to-TTL programmer needed when using another Pro Mini to program a Pro Mini to avoid the voltage problem, with the used mini measuring clips I can program other Arduino boards, etc...

Don't forget to uncomment #define USE_OLD_STYLE_WIRING in the ArduinoISP sketch in the examples to use the 'old style' connection like I did in my schema.

Edit 2020-11-24
(Re)Programming a Pro Mini with already connected hardware like a radio RFM69HW who uses also the pins D11(SCK), D12(MISO), D13(MOSI), can interfere with the ISP programmer. In one case, the Pro Mini was not correctly identified as a 328 device: “Yikes! Invalid device signature”.
The solution in that case, is to disconnect temporarily the external hardware.

Maybe this can help other people struggling with the same problem...

@skywatch Thanks for wanting to help me.
I have also the SDR# software installed, but was getting quicker a visual result with the other software, that's why I used this software.
So I'm curious how to set my sdr to the optimum level by adjusting the gain.

For photo's you can see them here : https://forum.mysensors.org/topic/11499/checking-mechanical-locked-doors-by-a-battery-based-windows-door-sensor-node
At the end, you have photos of the problem node.

Like said, today, the node was working.
I've reprogrammed also the repeater node, because I was doing a new temperature repeater node and remarked that my sketch code of the first repeater node was missing my encryption key???
I don't know what did happen here. The repeater node was recognized by the gateway and the controller, so the used encryption key is normally correct. Or is a presentation message not encrypted???
Maybe I did a mistake in saving my github sketch where I delete my keys of course
To be sure, I reprogrammed the repeater node with the correct encryption key.

If it happens again, I will check the spectrum and in case it isn't sending something, I will check the node on soldering errors and move also the node upwards in the doorframe.

I will check also the MySensors docs to see how we can see if a repeater node is working and how we can see that a sensor node is using the repeater and not trying to send directly to the gateway.

@Yveaux I'm already using your VCC library

@APL2017 Did you find the reason for this problem of reading periodically 0cm?
I have the same problem with a Arduino Uno connected to a HC-SR04 sensor. (in reality I made two sensors and both have regularly 0cm as output)
I can blindly adapt the software to filter out these strange values, but like you, I prefer to understand why this behaviour?

If you connect your laptop to the node's serial output, do you see some output in the serial monitor? Does the Arduino still communicate via the serial monitor?

If yes, the arduino is still working --> it can be the radio (is the antenna soldered in a correct way, is the elco capacitor soldered correctly, ...)

If no, the arduino is soft crashed for some reason.
Do you have other working nodes with the same sketch? If yes, the sketch should be correct because the other nodes are still working after x days.
If no, there could be a software problem. But then we have to see the sketch...

@Leon your node is sending a request to find a parent, in this case your gateway, but your gateway is not responding.
Without more information it will be impossible to help you further...

The sketch of the arduino can help, the config file of the Pi gateway, activating the log option in the configuration, ...

On the hardware side, verify your connections to be sure, did you use the capacitor next to the nrf24?, ...

@jvdk What you want to do is possible, but requires a certain amount of electronics hardware knowledge and programming skills.
I think this setup is not a standard within the mysensors library.

Perhaps you should first ask yourself why you want to communicate with the gateway by wire?

The sketch you have found to work with the ultrasonic sensor, normally sends its data via the radio module.
This can be replaced by a serial protocol transport to the gateway, but you will have to write that yourself on both sides, both on the arduino and on the gateway.
There are plenty of examples of code where arduino's talk to each other via the serial ports. On the Pi side you will also have to implement the same serial protocol.
On the hardware side, you must take into account that the distance between the arduino and the Pi, is limited. The arduino and the Pi use a serial signal based on 5V. Be careful with arduino's that run on 3.3V, you will need to put a converter in between. If you want to bridge long distances, you will have to go to an RS485 implementation and not a serial RS232 implementation.

Probably you want a wired solution because of the water tank.
I've read already topics about it, I even think on this forum, about people who did build something equivalent.
You can maybe search first other topics about this to get ideas of building this type of sensor.

@jvdk I don't use a raspberry pi, but searching on this forum I found this topic : https://forum.mysensors.org/topic/11315/raspberry-pi-zero-gateway-with-local-sensor
(important : read the comment to use wait() and NOT delay())
You could get in touch with the author if you have questions.

@tssk In following post I have described my adventures in building a battery powered door node : https://forum.mysensors.org/topic/11499/checking-mechanical-locked-doors-by-a-battery-based-windows-door-sensor-node?_=1614421889744
Search for the section : The battery-based windows/door sensor node : software
I explain there the use of the minicore package.
See also the section References at the end for more information about battery powered nodes

Sorry, but I'm afraid I can't help you any further.
If the tests in the sketch do not go any further, there is something wrong with the board itself...

Do you mean to remove the RFM69HW chip or the complete RFM69HW sub-board?
Removing the sub-board should be possible with a normal soldering iron and a desoldering pump sucker tool.
On internet you will find plenty of information how to desolder components, even on youtube where you can see it...
What for type of soldering iron do you have?

If the provided tests are not passing, there is something wrong.
Can you post some photo's of your board and solderings?

The log output is still the same : the transport is not found.

I would verify and measure the connections of the radio module to the ATSAMD21 µProcessor.
See schematic at https://www.mysensors.org/hardware/sensebender-gateway, search MysensorsGW.pdf
If these are all correct, a faulty RFM69?

Use following for the log parser:

MCO:BGN:INIT GW,CP=RRNGSA--,VER=2.2.0
SGN:PER:OK
SGN:INI:BND OK
TSF:LRT:OK
TSM:INIT
TSF:WUR:MS=0
!TSM:INIT:TSP FAIL
TSM:FAIL:CNT=hu
TSM:FAIL:DIS
TSF:TDI:TSL

This will output:

I would recheck the radio module connections...

@emre299 when you click on Burn Bootloader, you get these errors

avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x03
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x03

So you verified the connections. Did you verify also with a multimeter? A wire can be broken internally

Do you have another pro mini to verify the connections?
I would try different settings like the normal settings 3.3V and 8Mzh externally, etc

If this does not work, I have no ideas anymore...

Ok, you programmed the blink sketch the first time via the ISP way of uploading

• the pro mini at 3.3V : works
• the pro mini at 2.3V : didn't do anything ==> this is already strange, it should also work

Then you did the same using the default way by uploading the sketch via the bootloader

• the pro mini at 3.3V : works
• the pro mini at 2.3V : works

And now you can't upload anymore new sketches to the pro mini.
Of course you upload your sketch with the pro mini again at 3.3V?

Further I should:

• double check your wirings
• is your programmer connected with fixed pinheaders or by folding the programmer a little in the holes of the pro mini? Verify if you have strong connections.
• Reprogram the bootloader. If this works, you should be able to upload a sketch.

Post some photo's that we can see something.