@nagelc This seems to me the proper way to do it. Presentation of data on web/app should not modify the actual data from the node itself. For now HA is a no go for me until I get a chance to look at the HA mysensors code to see what it is doing.

@gohan I am using node-red in the middle because I have other locations I am sending my sensor data (SQL database, etc). The MySensors MQTT gateway talks on mygateway1-(out/in) and it works great. But, Domoticz requires a different topic as listed here (https://www.domoticz.com/wiki/MySensors#Configuring_the_MQTT-gateway_sketch
For Domoticz to work without additional software (like NodeRED), you will have to set MY_MQTT_PUBLISH_TOPIC_PREFIX to "domoticz/in/MyMQTT" and MY_MQTT_SUBSCRIBE_TOPIC_PREFIX to "domoticz/out/MyMQTT".

Node-red is great for this sort of stuff. I re-broadcast the mygateway1 on the domoticz topic.

I did not add a gateway any differently in HA vs Domoticz - I pointed it at the MQTT topic (in HAs case it is the mygateway1 and for Domoticz it is domoticz). HA happens to send back to the gateway (on an MQTT topic I imagine) the setting to change to imperial from metric (which is the default). But, Domoticz did not do this. I think maybe Domoticz gets the metric/imperial setting from the gateway and then, depending on the Domoticz units configuration, converts the value to be shown on the front end. I suppose the next thing for me to try is just use MQTT on HA without setting up the mysensors gateway explicitly. But, not sure how HA would know to convert my values to imperial. Or, I could just re-code my nodes/gateway to force imperial at all times.

So, first here is my general setup:
Multiple DS18B20 temp sensors sending data in metric.
One ESP8266 gateway that is using the MQTT protocol.
A mosquitto broker running on an RPi
Node-red running on the same RPi that re-broadcasts the MySensors topics (mygateway1-out/blah) on the Domoticz required one (domoticz/in/MyQTT/blah).
The same RPi with latest 4.97 Domoticz install listening on their MQTT topics. Domoticz is set to use imperial units of measure.
All is working as it should.

Last night I installed HomeAssistant (not HASS.io) on my laptop and set it up to use the MySensors protocol and to listen in on the mygateway1-out/# topics. And, of course, I set the HA temp units to imperial. Messed around a bit and decided that enough was done for the night (could not get it to talk to my smart TV).

I then checked my Domoticz dashboard and saw that, well, my house was turning into an oven! The 2 sensor nodes are now reporting temps of 170F! I look at the Domoticz log and it isn't a transient event. I then look at node-red in debug and see that the mygateway1-out is sending out F values instead of C values and Domoticz is converting the values from C to F...but the numbers are already F - so, yay, I get massive wonkiness!

I go back into HA (fire it up again) and change the units system from imperial to metric and, next sensor report cycle, the values are back to being sent in as C. What the ever loving hell? Let's dig into the code a bit.

In the nodes there is this bit:

// Fetch and round temperature to one decimal
   float temperature = static_cast<float>(static_cast<int>((getControllerConfig().isMetric?sensors.getTempCByIndex(i):sensors.getTempFByIndex(i)) * 10.)) / 10.;

Okay, so it asks the controller what it should report in.

• But, why did this change with the HA settings change?

• If HA was just listening on the MQTT topic what the hell is it doing communicating back to the node to tell it use imperial? Can I turn this off and have HA report the correct value (in C) and unit (convert to F)?

• If Domoticz is just listening on the the MQTT topic why is it not telling the gateway to use imperial?

I am very confused by this. If I decide to have my nodes report in F how the hell is Domoticz going to handle that? Do I then have to change Domoticz settings to C to get the real number but have incorrect units assigned?

I really don't think the HA settings - unit change should have any impact whatsoever on the actual number sent from a node. It is purely presentation layer not data layer. There should be a method to tell HA that "values sent are in metric" and if the front end unit is set to imperial it should convert the raw number on HA's side - not change the settings on the gateway.

@stkilda It really depends on how much "control" you want. I run mosquitto broker, node-red (for handling lots of MQTT messages and for internet API calls), and for my controller I use Domoticz. All of this on my raspberry pi 2 B. I have around 1% CPU usage and ~25% RAM usage. There is not a lot of cross-traffic on my system (meaning I only send data to Domoticz from nodes and not the other way around). This works just fine. You can do the same on your laptop given any OS you want to use - your install and config will of course be different. Yes, you need to have your controller on all the time.

Domoticz is the easiest to get up and running. All you need is an ethernet/serial gateway and off you go. I use the MQTT gateway and Domoticz requires its own MQTT topic (lame) but that is easy to setup on node-red (I just rebroadcast my MQTT gateway messages on a the Domoticz topic).

@chisight I had done the raw file import. Issue I was facing was with the single/double quotes being interchanged. Easy fix. I am not sure if my "fix" for the VString was necessary. I just wanted to see what each sensor value was going to return. I need to get my DB setup a little better (using SQL Server as I cant stand the rigidness of time-series DBs like Influx).

A little clean up in notepad++ and I have a working flow!
I made some modifcations (of course) for my setup. The main one is the ability to get the sensor value type. Initially the code in the Parse node did:

// msg.topic = context.global.MYS.TOPIC_PREFIX + '/' + msg.controller + ' / ' + msg.nodeId + ' / ' + msg.childSensorId + ' / ' + msg.subTypeString;


 var tokens = msg.topic.split('/');
 
 msg.rawData = tokens;
 if(tokens.length >= 5)
 {
 msg.controller = parseInt(tokens[1]);
 msg.nodeId = parseInt(tokens[2]);
 msg.childSensorId = parseInt(tokens[3]);
 msg.subTypeString = tokens[4];
 msg.subType = context.global.MYS.VNum(msg.subTypeString);
 msg.command = 1; // SET
 msg.acknowledge = 0; // no ack as default
 }

return msg;

I modified the msg.subType to use:

msg.subType = context.global.MYS.VString(msg.subTypeString);

Now to set this up to write to my DB.
Many thanks to @FotoFieber and @chisight

@chisight I attempted to use this code but node-red would not let me import. Checked the json online and it does not appear to be valid.

Christmas wreathe for the techie in all of us.
pretty colors
flashing
wire wrapping

Uses a pro mini and a lot of wire-wrapping. Other components on the circuit boards are just there for show.

(ugh, google photos links not showing up so converted to links)

So, got my ESP8266 and set it up as the ethernet gateway. Removed the on-board RPi gateway. Domoticz picked up the new gateway easily enough (this has never been an issue). Now, turned on my nodes (with static nodeIDs) and the gateway picked up one of the two nodes (why? no idea). Sent presentation to gateway then to Domoticz. Domoticz sees the humidity sensor as S_UNKNOWN but with V_HUM values???? I have no idea what is happening. The ESP gateway log shows the sensor as S_HUMIDITY just fine. So, this is a new wrinkle. But the same issue persists - temp/hum updated on the Hardware view of the gateway but Device view of that sensor is never updated from initial state. I am this close to taking the whole system out back with a baseball bat.

So, status now:
Only 1 of 2 nodes seen by gateway (unique IDs on both)
The 1 node values are sent to gateway around every 5 minutes (with new values as tested over night)
Domoticz does not update the Device with any new values from initially seen data
Gateway serial log is showing updates just fine
MYScontroler running on my Windows box also sees the updates just fine
OpenHab2 does not see any updated from initially seen data
Stress level at 100%

So, since updating to beta release on 11/2 it has now been 5 days since the Device value has been refreshed. Every time I go to check the Hardware view it is updated and has new/diff values. This is stupid.
I have now updated to the latest Domoticz beta in hopes something changes.