I have built the Arduino ethernet gateway, this is the sketch I uploaded:

/**
 * 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) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/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
 * Contribution by a-lurker and Anticimex,
 * Contribution by Norbert Truchsess <norbert.truchsess@t-online.de>
 * Contribution by Tomas Hozza <thozza@gmail.com>
 *
 *
 * DESCRIPTION
 * The EthernetGateway sends data received from sensors to the ethernet link.
 * The gateway also accepts input on ethernet interface, which is then sent out to the radio network.
 *
 * The GW code is designed for Arduino 328p / 16MHz.  ATmega168 does not have enough memory to run this program.
 *
 * LED purposes:
 * - To use the feature, uncomment MY_DEFAULT_xxx_LED_PIN in the sketch below
 * - RX (green) - blink fast on radio message recieved. In inclusion mode will blink fast only on presentation recieved
 * - TX (yellow) - blink fast on radio message transmitted. In inclusion mode will blink slowly
 * - ERR (red) - fast blink on error during transmission error or recieve crc error
 *
 * See http://www.mysensors.org/build/ethernet_gateway for wiring instructions.
 *
 */

// Enable debug prints to serial monitor
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

// Enable gateway ethernet module type
#define MY_GATEWAY_W5100

// W5100 Ethernet module SPI enable (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.
#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 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 to UDP
//#define MY_USE_UDP

#define MY_IP_ADDRESS 192,168,1,194   // If this is disabled, DHCP is used to retrieve address
// Renewal period if using DHCP
//#define MY_IP_RENEWAL_INTERVAL 60000
// The port to keep open on node server mode / or port to contact in client mode
#define MY_PORT 5003

// Controller ip address. Enables client mode (default is "server" mode).
// Also enable this if MY_USE_UDP is used and you want sensor data sent somewhere.
//#define MY_CONTROLLER_IP_ADDRESS 192, 168, 1, 131

// The MAC address can be anything you want but should be unique on your network.
// Newer boards have a MAC address printed on the underside of the PCB, which you can (optionally) use.
// Note that most of the Ardunio examples use  "DEAD BEEF FEED" for the MAC address.
#define MY_MAC_ADDRESS 0x5A, 0x41, 0x42, 0x76, 0xE6, 0xB1

// 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 7  // Error led pin
//#define MY_DEFAULT_RX_LED_PIN  8  // Receive led pin
//#define MY_DEFAULT_TX_LED_PIN  9  // Transmit led pin


#if defined(MY_USE_UDP)
#include <EthernetUdp.h>
#endif
#include <Ethernet.h>
#include <MySensors.h>


void setup()
{
}

void loop()
{
}

When connecting the gateway to an ethernet port, I can ping the gateway on its IP.

But Home Assistant can't connect to it:

2017-12-07 14:12:37 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:12:37 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)
2017-12-07 14:12:46 INFO (Thread-2) [mysensors.gateway_tcp] Closing socket at ('192.168.1.194', 5003).
2017-12-07 14:12:46 INFO (Thread-2) [mysensors.gateway_tcp] Socket closed at ('192.168.1.194', 5003).
2017-12-07 14:12:46 INFO (Thread-2) [mysensors.gateway_tcp] No response. Disconnected.
2017-12-07 14:12:46 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:12:46 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)
2017-12-07 14:12:57 ERROR (Thread-2) [mysensors.gateway_tcp] Receive from server failed.
2017-12-07 14:12:57 INFO (Thread-2) [mysensors.gateway_tcp] Closing socket at ('192.168.1.194', 5003).
2017-12-07 14:12:57 ERROR (Thread-2) [mysensors.gateway_tcp] Failed to shutdown socket at ('192.168.1.194', 5003).
2017-12-07 14:12:57 INFO (Thread-2) [mysensors.gateway_tcp] Socket closed at ('192.168.1.194', 5003).
2017-12-07 14:12:57 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:12:57 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)
2017-12-07 14:13:06 INFO (Thread-2) [mysensors.gateway_tcp] Closing socket at ('192.168.1.194', 5003).
2017-12-07 14:13:06 INFO (Thread-2) [mysensors.gateway_tcp] Socket closed at ('192.168.1.194', 5003).
2017-12-07 14:13:06 INFO (Thread-2) [mysensors.gateway_tcp] No response. Disconnected.
2017-12-07 14:13:06 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:13:06 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)
2017-12-07 14:13:17 ERROR (Thread-2) [mysensors.gateway_tcp] Receive from server failed.
2017-12-07 14:13:17 INFO (Thread-2) [mysensors.gateway_tcp] Closing socket at ('192.168.1.194', 5003).
2017-12-07 14:13:17 ERROR (Thread-2) [mysensors.gateway_tcp] Failed to shutdown socket at ('192.168.1.194', 5003).
2017-12-07 14:13:17 INFO (Thread-2) [mysensors.gateway_tcp] Socket closed at ('192.168.1.194', 5003).
2017-12-07 14:13:17 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:13:17 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)
2017-12-07 14:13:26 INFO (Thread-2) [mysensors.gateway_tcp] Closing socket at ('192.168.1.194', 5003).
2017-12-07 14:13:26 INFO (Thread-2) [mysensors.gateway_tcp] Socket closed at ('192.168.1.194', 5003).
2017-12-07 14:13:26 INFO (Thread-2) [mysensors.gateway_tcp] No response. Disconnected.
2017-12-07 14:13:26 INFO (Thread-2) [mysensors.gateway_tcp] Trying to connect to ('192.168.1.194', 5003)
2017-12-07 14:13:26 INFO (Thread-2) [mysensors.gateway_tcp] Connected to ('192.168.1.194', 5003)

And this is the serial debug output from the gateway:

0;255;3;0;9;MCO:BGN:STP
0;255;3;0;9;MCO:BGN:INIT OK,TSP=1
0;255;3;0;9;Eth: connect
0;255;3;0;9;MCO:BGN:INIT GW,CP=RNNGA--,VER=2.1.1
0;255;3;0;9;TSM:INIT
0;255;3;0;9;TSF:WUR:MS=0
0;255;3;0;9;TSM:INIT:TSP OK
0;255;3;0;9;TSM:INIT:GW MODE
0;255;3;0;9;TSM:READY:ID=0,PAR=0,DIS=0
0;255;3;0;9;MCO:REG:NOT NEEDED
IP: 192.168.1.194
0;255;3;0;9;MCO:BGN:STP
0;255;3;0;9;MCO:BGN:INIT OK,TSP=1
0;255;3;0;9;Eth: connect
0;255;3;0;9;MCO:BGN:INIT GW,CP=RNNGA--,VER=2.1.1
0;255;3;0;9;TSM:INIT
0;255;3;0;9;TSF:WUR:MS=0
0;255;3;0;9;TSM:INIT:TSP OK
0;255;3;0;9;TSM:INIT:GW MODE
0;255;3;0;9;TSM:READY:ID=0,PAR=0,DIS=0
0;255;3;0;9;MCO:REG:NOT NEEDED
IP: 192.168.1.194
0;255;3;0;9;MCO:BGN:STP
0;255;3;0;9;MCO:BGN:INIT OK,TSP=1
0;255;3;0;9;Eth: connect
0;255;3;0;9;MCO:BGN:INIT GW,CP=RNNGA--,VER=2.1.1
0;255;3;0;9;TSM:INIT
0;255;3;0;9;TSF:WUR:MS=0
0;255;3;0;9;TSM:INIT:TSP OK
0;255;3;0;9;TSM:INIT:GW MODE
0;255;3;0;9;TSM:READY:ID=0,PAR=0,DIS=0
0;255;3;0;9;MCO:REG:NOT NEEDED

This is my configuration.yml for Hass:

<snip>
mysensors:
  gateways:
    - device: '192.168.1.194'
<snip>

Why can't Home Assistant connect to the gateway, and why does the gateway seem to be stuck in some kind of loop?

I have built the ethernet gateway using an Arduino and a wiz5100 ethernet board. I can ping the board on its configured IP address from my computer.

I have HASS running in a container locally (to test it out).

The gateway has no sensors yet, but I'd expect it to be visible in HASS before I can add any sensors.

How do I get HASS and the ethernet gateway to know about each other?

@manutremo Does the battery have undervoltage protection built-in, or do you have separate circuitry to handle it? And how do you recharge the battery?

@gohan Good to know, thanks. I was thinking once or twice an hour maybe. It looks like I'd have to use a 3.6V 18650 type of battery, or 3x AAA to get the 3.3V required by this, correct?

The BME280 looks interesting and costs 2$ on eBay. Any experience running it on batteries?

I wouldn't know what to offset for, I have 5 sensors and they all have different offsets. What's more, the offset varies with temperature and RH, i.e. it's not a linear offset.

Hello,

I am playing with a few DHT22 sensors, and I find them very inaccurate. The spec says they're +/- 0.5C and +/- 2%RH but I find that to be false. And they don't even all agree with the measurements even when put in the same spot and checked at the same time.

What alternatives are there for a sensor that reliably measures RH and temperature (all in one package if possible, and battery friendly)?

I'd like to use it to monitor the inside of a fridge, and inside rooms.

Thank you

Pardon me if this is a dumb question, I've seen in other messages that people talk about having multiple sensors all hooked up on one Arduino + nRF24.

I also see in the docs that present() takes two arguments, one of which is child-sensor-id.

Am I understanding correctly that one Arduino + NRF24 (I'm guessing that is what a node is?) can report data from more than one sensor?

I have about a dozen plants sitting one next to another, it would be great to sense moisture in each pot without requiring ten Arduinos and ten NRF24; but rather one Arduino and one NRF24 reading from ten moisture sensors, all appearing as separate "plants" in the controller and triggering separate alerts when low on water (so I can tell which plant specifically needs watering).

Did I get that right? Can I get away with one Arduino + one NRF24 reporting data from 10 moisture sensors?

This looks very interesting, and I have most of the parts lying around. However, there are a few questions I couldn't find the answers to:

• For sensors that are battery powered, do they trigger some kind of alert when the batteries are low and must be replaced?
• The NRF24 radio uses 2.4Ghz. Does it work well in locations where the 2.4Ghz WiFi band is so saturated that it's barely usable? Is there a 5Ghz option?
• It says that if you don't use the Wiz5100 ethernet module for the gateway, you can use the ENC28J60 but with reduced functionality: what is missing from the gateway if you use that second module?
• What about encryption? Can anyone read my sensors' values over the air, and potentially transmit bogus sensor data?
• What is the prefered open source controller to run on a Linux server/container?

Thanks,