I really like this proposal.

What it would give us:

• Multiple variables of the same type (like two temperatures)
• The possibility for human description of a variable (core temp, air temp, engine temp)
• The possibility to describe the values even if they don't exist (Say if temperature didn't exist we could describe it as a LEVEL with the unit °C
• The possibility to describe the range of values (I.E. This temp may be between 0-25°C)

This doesn't need to be handled by the gateway, it could be moved to the controller which usually are a high-performance device. And if it isn't (doesn't have room to store the configuration) it may ask the node for it every time it receives a value from the node. In this configuration the gateway would just be a translator between nrf24 and USB, or nrf24 and Ethernet or whatever.

@epierre MySensors is GPL so all code needs to conform with that, which CC doesn't. Also CC isn't for code.

I actually saw some Arduino projects on ATtiny, however I didn't thought of the IO problem.
Guess I will have to kill that idea.

Thanks both of you for the fast response :)

I would like to use small 8pin AVRs for nodes with only one sensor (like temp).
Is ATtinys supported?

I'm sorry if this is a dumb question, I'm new to the Arduino and AVR world.

Please leave HSV/HSL to the controller. Why complicate the node more that necessary?
Using LEVEL would be good, 8 bit per color is good, it's also super easy for the node to scale down if only supporting 7 or 6 bits and it's perfect for those digital LED strips.

Please have a pure RGB without W, most strips and RGB leds don't have a W diode so that would need to be simulated with different result in different nodes.

@hek
That would probably do it, however one would need to be defined and standardized so that all behaves the same. One more clever than me needs to propose how the curve would look tough.

V_R_PERCENTAGE - Red component % <int>
V_G_PERCENTAGE - Green component % <int>
V_B_PERCENTAGE - Blue component % <int>
V_W_PERCENTAGE - White component % <int>

Just a hundred steps might be to low, especially for green in the lower end which the eye sees much brighter.
Please consider floats or per thousand instead.

@Yveaux Okej, Thank You!

Could the line quality information be queried directly by the gateway so that it can be known without additional hardware?

I have thought a bit about this, not from a MySensors perspective but as a Controller perspective as I'm developing one.
For me SensorType can be interesting (however it will need to be remodeled a bit). If I get a temperature from the sensor,
it's probably a Thermometer, but it may be the inner core temperature or something else. If I get a unit that supports turning
on or off it may be a Lamp, but it may also be a bunch of other things. To create the best experience for the user I would
need to know not just that it's a temperature reading, but from where.

So for this to work S_TEMP would be S_THERMOMETER. Then I know that a V_TEMP is a environment temperature
reading and not a inner core temperature. Obviously all of the SensorTypes would have to be looked over if they need
similar changes.

So, I would prefer if SensorType described what a human would classify a sensor node as.

I would also prefer if all units reported were in SI units. If a user want to display the as something else, that is a display
setting and nothing else.

Interesting!
I believe your choices are great between size and functionality for a non specific use case.