2.0 Discussion: Units, sensor types and protocol

[Zeph]

@John

I can see a case for making HSB the norm.

Think of light types like a class heirarchy, with added functionality

S_BINARY

V_STATUS (1=100%, 0 =0%)

S_DIMMABLE

V_STATUS (1=100%, 0 =0%)
V_PERCENTAGE (0.0% - 100.0%)

S_HSB

V_STATUS (1=100%, 0 =0%)
V_PERCENTAGE (0.0% - 100.0%)
V_HUE (0.0 - 360.0)
V_SATURATION (0.0% - 100.0%)

If you set V_STATUS to 0, or V_PERCENTAGE to 0%, any of these lights turn fully off.
If you set V_PERCENTAGE to 100%, S_DIMMABLE will go to 100% (V_STATUS=1)
and S_HSV will go to 100%, in the current hue and saturation
If you set V_PERCENTAGE to 50%, likewise.

I think one could make the case that it's more human compatible to go to "yellow, 25%" than to figure out what the RGB values would be. (The user interface could translate yellow to a hue number)

One aspect HSB is that there are a couple of ways of associating colors with angles, so we would need to specify which is our standard, so 40 degrees is the same hue for all nodes. I like the rainbow style.

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@hek
I do also get the point that HSB -> RGB conversions could be done on the controller, passing the lower level RGB values to the node. There is an attraction to that as well.

This cannot be fully resolved without also considering the question of light curves or gamma factors, which has been raised. The controller needs to know whether or not the node implements light curves for RGB channels, so it can avoid doing that twice; and also it in the changes how the controller should convert HSB to RGB (the stock conversions assume RGB are linear).

[Zeph]

@Damme said:

Write it down

That's what I'm trying to do.

We could CLEARLY write down that V_WATT is intended only to report values and cannot be set, while V_RESET is a trigger, and V_R_PERCENTAGE is settable - so different implementors don't make different and incompatible guesses about what these mean.

We do not want the situation where one sketch writer interprets V_WATT to be a way to control how much power the lamp will use and another sketch write interprets it as reporting only. And then controller interface writers also guess differently about what it means. That's chaos.

One step in that direction would be naming them according to the intention - writable, reportable, or trigger.

I've done a LOT of implementing from specifications, as many others have. Having a clear specification that avoids huge ambiguities (is this something you set or something that reports is huge) is not over-thinking - it pays off big time.

[Yveaux]

@hek said:

Crazy

You didn't dare posting a red version, did you?

[John]

@Zeph

I can see a case for making HSB the norm.

I'm not ;). it is just a possible addition of possible value types to the S_RGBW type and if not possible like you stated a S_HSB and to keep clarity V_PERCENTAGE should then be V_BRIGHTNESS. Or both percentages (not possible) or both naming as it is.

One aspect HSB is that there are a couple of ways of associating colors with angles

Off topic, which ones? i only know one, are you sure your not mixing HSB with HSL?

On topic:
I'm fine with only sending RGB if HSB ain't possible to be combined with S_RGBW or added with S_HSB/S_HSV if it is thought of as a logical addition.

[Zeph]

@John
You are probably way ahead of me in terms of formal color spaces. I'm just a color user.

I like using a modified Hue, such the the "rainbow" described here:

https://github.com/FastLED/FastLED/wiki/FastLED-HSV-Colors

[John]

@zeph said

You are probably way ahead of me in terms of formal color spaces

Not really, i'm no color expert, But did a lot with colors lately because i use this to influence our living environment

Ok got it, Hue with rainbow style is variable due to the amount of colors (real life circumstance like angel etc) on that page an almost perfect rainbow angle and lighting situation is used.

I agree with you, but that's user implementation on the hardware, and something mysensors can not control. You would still need the HSB parameters The implementation of rainbow or spectrum should be done on the controller<->end device side and the end user should know about it (or at least the developer of that specific controller/hardware implementation), not protocol based, because the parameters are still the same.

[epierre]

@Hek globally I don't understand the min/max/average, are they managed by the sensor or the controller ? if it is the sensor in case of reboot it should get it back from the gateway/controller and should be resettable maybe to have a year/month/week/day min/max. For me that should be controller side to handle this logic...

Now for my favorite playground it needs the calibration value clearly first, then for the discussion some projects (AirPi) avoid the calibration pitfall by sending back the voltage... If we want to have a concentration value from the sensor that is ok.

 S_AIR_QUALITY - Air Quality Sensor
 V_LEVEL - ? We need to describe this better
 V_LEVEL_RESET - Reset max/min value

@hek Hmm.. Soil Moisture.. I have no idea how to represent this. Help me! The ebay sensors we're using isn't super accurate and comes uncalibrated.

@damme   Hmm... V_Moisture, (relative) 0-255 / 0-100% / True | False

On both I agree, I have some imaginatronix and yes you need a margin of error... but when it rains it rains... this is where a calibration value will be usefull at least to have several sensors showing the same value at the same environment time... I you want a logic then the true false can be good but not enough... on my imagitronix I have an empty value of 20% and a watered value of 100%, sometimes after the rain it is 80%..., where would be the limit ?

Also, I am thinking of a leaf wetness (we had a lot here this year... and diseases that goes with it) that could be mapped to soil sensors [Article on values(http://www.decagon.com/education/do-you-measure-leaf-wetness/)

[hek]

@epierre said:

globally I don't understand the min/max/average, are they managed by the sensor or the controller ? if it is the sensor in case of reboot it should get it back from the gateway/controller and should be resettable maybe to have a year/month/week/day min/max. For me that should be controller side to handle this logic...

The MAX/MIN/AVERAGE are optional to use. My idea was that sensors would manage them. They can choose to store it in eeprom or throw away values when reboot occurs.
The idea originates from GUST for wind which really is a max value over a certain time. This is just a generalization.
Usecase: Sensor might not report every wind value to controller but just every 10 minute. But internally it can calculate average/max/min for every 10 seconds without pushing this.

[Rasmus Eneman]

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.

[John]

@Rasmus-Eneman

Please leave HSV/HSL to the controller. Why complicate the node more that necessary?

That's why i asked for an addition if it would over complicate stuff (and if there is room for it) ;). And well, yeah you're right, S_RGBW with HSB would be complicating things more mixing capabilities with the node naming. There is always S_CUSTOM with V_VAR_1,V_VAR_2,V_VAR_3 combination.

I agree with leaving out the W. But could be a nice addition for those non calibrated fixtures where you have to supply calibrated values in the node to get "proper" white levels.

[epierre]

@hek ok I agree. Can we have too an alert that could be sent back to the gateway, or like an armed mode for the air sensors ?

Today, one of my daughter broke a bottle of perfume, saturating the air and making the sensor go to its max. Even if the sensor is not calibrated, on some kind that (IMHO) must raise an alert for I cannot say infinite or over the maximum value...

[Yveaux]

@epierre In 1.4 a binary represetation of a float value can be exchanged with the library. This allows to report e.g. + or - infinite where normally floating point values are sent. Maybe this will serve your purpose?

[Zeph]

If you do have a strip with RGB and W LEDs (rare), this can be handled as an RGB light and a DIMMER.

---

A lot of our discussions really hinge on how much smarts to put where in the architecture. My overall philosophy would be to keep the node simple and move functionality to it only when the same thing cannot be easily done centrally. Reasons to move smarts into a node could include:

• Uses local calibration that central doesn't have
• Needs updating more often than reports go to central (eg: wind max)
• Timing, eg: safety features that need to act fast
• Reliability of data links, eg: safety features that should not depend on RF robustness
• Providing some logically consistent interface available to all controllers
• Providing some functionality which cannot be as easily implemented in a controller (eg: closed source)

The latter two would be one-off custom coding at this time, tho @hek has mentioned the idea of pushing some rules down to the node level in a more automated way someday.

---

This probably argues more for using RGB rather than HSV at the node level. What I liked about the HSB was the unification of on/off, dimmable, and HSB functionality as a nested set of expanding functionality. So a script or rule that sets the brightness could work on a DIMMABLE or a HSB light by setting the V_PERCENTAGE value (or V_BRIGHTNESS as someone suggested). But that could be done at the central level.

---

I've used the term "central" because I still have the vision that a "hub" or "gateway" could implement some features, rather than having the smarts only in the controller or in the sensactuator nodes. So for example, it could be possible for the gateway to convert HSB to RGB such that the controller doesn't have to implement it. I know that approach is not currently popular so you don't need to register general disapproval. This will either come to seem a worthwhile additional open in coming years or not.

[Zeph]

@epierre said:

Can we have too an alert that could be sent back to the gateway, or like an armed mode for the air sensors ?

Today, one of my daughter broke a bottle of perfume, saturating the air and making the sensor go to its max. Even if the sensor is not calibrated, on some kind that (IMHO) must raise an alert for I cannot say infinite or over the maximum value...

Let's not bring infinity into this...

How about just returning "the maximum reportable value" (finite). If the node is capable of detecting "above measurable" conditions, have it define the "maximum reportable" as 1 higher than it's internal "maximum measurable".

The idea is to keep a simple scale of results, where for example we can consistently compute "max/min over 24 hours", or set a trigger on "value >= threshold" without needing to deal with infinity math. Some controller software may not have any concept of infinity, so using it brings in unnecessary incompatibilities.

This allows the controller to define the alert as it wishes. For example, suppose a sensor reports uncalibrated values of 25 to 173, and the node uses 174 for a detected "over-range". The controller can implement a trigger or event at "value > 160" to test for high values (without having to test for infinite values too). Or it could test for "value >=174" if it specifically wants to test for overrange (which could be way over the max measured value or just barely above it).

[hek]

@epierre said:

Today, one of my daughter broke a bottle of perfume, saturating the air and making the sensor go to its max. Even if the sensor is not calibrated, on some kind that (IMHO) must raise an alert for I cannot say infinite or over the maximum value...

LOL

[epierre]

@Zeph I don't share the same view, since we allow logic in the sensor for min/max interval, why not doing it too for the gas level ? all the more that the limit of the sensor is not a "business logic" but an internal logic linked by the physical capacity of the sensor itself (and which varies with each sensor type...).

My point was more that if you monitor LPG NO2 / NO3 or smoke that could be really harmfull we should provide safeguards anyway... not a big deal, more a safety net...

[hek]

Ok,

I will change create two device-types S_RGB and S_RGBW and use a level instead of percentage for each color component (0-255).

[epierre]

For my sound sketch :

S_SOUND - Sound sensor

V_LEVEL - sound level in db
V_LEVEL_MAX - Max sound level
V_LEVEL_MIN - Min sound level
V_LEVEL_AVERAGE - Average sound level
V_LEVEL_RESET - Reset max/min value

[epierre]

For my vibration sketch :

S_VIBRATION -Vibration sensor

V_LEVEL - vibration level in Hertz
V_LEVEL_MAX - Max vibration level
V_LEVEL_MIN - Min vibration level
V_LEVEL_AVERAGE - Average vibration level
V_LEVEL_RESET - Reset max/min value

[epierre]

@zeph the smoke sensor is an Air Quality sensor in fact so we coud decribe it this way too.
@hek what about the V_GAS_TYPE proposed below ? that would limit extensing the S and V no ?

S_AIR_QUALITY - Air Quality Sensor

V_GAS_TYPE - gas type reported by the sensor
V_LEVEL - gas concentration in ppm/ppb
V_LEVEL_MAX - Max gas concentration level
V_LEVEL_MIN - Min gas concentration level
V_LEVEL_AVERAGE - Average gas concentration level
V_LEVEL_RESET - Reset max/min value
V_STATUS - Tripped status of a gas sensor. 1=Tripped, 0=Untripped
V_ARMED - Armed status of a security sensor. 1=Armed, 0=Bypassed

[hek]

@epierre said:

S_SOUND - Sound sensor

Wouldn't it be good to have a uncalibrated variable for S_SOUND also? Like proposed for S_LIGHT_SENSOR. Reported as:

V_PERCENTAGE - 0-100%

[epierre]

@hek hopefully all smartphone now have a calibrated microphone that could help calibrate this... what 'Ive not worked out enough is to know if the store sensor is suitable for this...

also I don't know what the semantic of "100% sound" would mean... max sensor capabilities ?

[hek]

@epierre said:

also I don't know what the semantic of "100% sound" would mean... max sensor capabilities ?

Yeah, something like (1023-analogRead(ANALOG_PIN))/10.23

[epierre]

@hek hmmm... what about if this is a 3.3V or a 5V arduino board too ? no ? ?

[daulagari]

Coming from the Can one child-sensor-id have multiple values thread I had a look at the initial post and I am wondering if this is what you can call "the latest proposal".

The rest of this thread seems to be more about which variables but what I am wondering is how all this would be implemented. Looking at the initial post I see:

New header would be:

ChildSensorId | ChildSensorType | ValueType | Payload

My assumption is that there is still a NodeID in the header, so actually:

NodeId | ChildSensorId | ChildSensorType | ValueType | Payload

If so, I think there is too much freedom/overhead in the first three fields.

My expectations as an user is that every sensor, or better "box" is one node and implements one type of sensor with one or more values. In this sense I do not see the use of the ChildSensorId field, so why not use:

NodeId | SensorType | ValueType | Payload

[hek]

Hmm... what if you want to report multiple temperatures from one node?

[Yveaux]

@hek said:

Hmm... what if you want to report multiple temperatures from one node?

Or for actuators, control multiple LEDs/Blinds etc. from a single node...

I think a few bits could at least be saved by limiting the amount of ChildId's per node.

[daulagari]

what if you want to report multiple temperatures from one node?

Does not sound to logical to me and I would be surprised if more than 1% of the implemented sensors have "double values", so the first question is if we want to carry an field for exceptions.

Multiple temperatures/LEDs/Blinds can still be implemented by adding an additional ValueType V_LEVEL_SECONDARY but a much cleaner approach would be to use another NodeId.

Let's also have a look at this from the perspective on how to represent things at the Controller:

• Is it logical to have two values of the same type reported for a node?
• How does the user know which temperature/LED/blind is what?

[Zeph]

@daulagari said:

Let's also have a look at this from the perspective on how to represent things at the Controller:

• Is it logical to have two values of the same type reported for a node?
• How does the user know which temperature/LED/blind is what?

This seems to depend on how you conceptualize the system. In @hek 's proposal and the current system, the core concept of an endpoint is the child aka "sensor". (I'm going to cal this the child/sensor; elsewhere it's often called a "sensor' which as you say can be confusing, but what we mean is the conceptual element addressed using a child id within a node)

The node is a device with an RF transceiver (addressed by node id which is part of the transceiver address), which contains and makes accessible one or more child/sensors, each identified by the node id and child id. The controller receives reports from child/sensors and sends commands to child/sensors. The node is just part of the transportation system.

The controller is configured to know what each child/sensor consists of..

In that context, your first question could be split:
Is it logical to have two values of the same type reported for a child/sensor?
Is it logical to have more than one child/sensor supported by a single transceiver+uC (ie: node)?

@hek made the point a while back that a child/sensor can be thought of as a semantic container for one (or sometimes more) closely related values. A node can contain one or more of those.

Yes, there would be an alternative, in skipping the child/sensor container layer. One approach would be to support only a single sensor per node, but there is clearly interest in multi-sensor nodes. Another would be to dissolve the child layer of this heirarchy use rules something like:

• a node can report on (or accept control for) more than one sensor, with more than one value
• no multi-sensor node can have more than one sensor which reports the same kind of value
• the controller will be responsible for logically grouping related sensor/control values within a node

I think one could get by with this for now, but I'm not sure it's a clean conceptual architecture to continue to expand for the future. And I wonder if it puts too much onto the controller - not a big deal if there was only one controller type supported (eg: Vera only), but with an expanding list of controllers, any functionality (like conceptual grouping of the values within a node into "sensor" containers) which is moved to the controller, requires that functionality to be programmed into every controller's architecture in whatever languages that requires - a lot of parallel maintenance to keep in sync for any changes. The less functionality is moved into the controllers, the easier it will be to maintain.

• How does the user know which temperature/LED/blind is what?

Exactly. Is this configured per value, or per child/sensor? (If no sensor ever had more than one value, this would be moot).

Currently the "what" is configured per child/sensor.

Suppose next year one wanted to measure the effectiveness of a swamp cooler with intake temperature and output temperature. Does that need to require two nodes, because the architecture was designed such that no node can report two temperatures?

If the goal is just to create an architecture which can get by for most systems today, there's not need for a big rethinking or the labor of rewriting the code - version 1.4 already does that. I think the point of this thread is to define a flexible conceptual base that's likely to be more cleanly extensible for a few years of growth. I think that hek's child/sensor concept is somewhat helpful in creating that flexibility. Perhaps there's an even better approach to serve that function, but just omitting the child/sensor container level doesn't currently strike me as such.

[RJ_Make]

I would agree, I rely heavily on the child/sensor container level. I typically build nodes that poll multiple types of sensors.

[marceltrapman]

Look at how other systems do this (for those that do not agree with the current setup).

Multi sensors are used all over the place.

The very well known temp/humid/lux/motion sensors but also tilt sensors combined with a tamper alarm.
And when it comes down to using more of the same sensors on one node: i am going to build a sensor that has two IR sensors for 2 directions.

[daulagari]

@Zeph , @ServiceXp, @marceltrapman Thanks for the feedback.

I would agree, I rely heavily on the child/sensor container level. I typically build nodes that poll multiple types of sensors.

and

The very well known temp/humid/lux/motion sensors but also tilt sensors combined with a tamper alarm.

Both are still perfectly possible.

And when it comes down to using more of the same sensors on one node: i am going to build a sensor that has two IR sensors for 2 directions.

That is what I think is the "less than 1% of the implemented sensors"

Note that the current proposal:

NodeId | ChildSensorId | ChildSensorType | ValueType | Payload

has one more field than the 1.4 protocol.

My proposal is basically to merge the ChildSensorId and ChildSensorType into one, being the ChildSensorType, so:

NodeId | ChildSensorType | ValueType | Payload

If the goal is just to create an architecture which can get by for most systems today, there's not need for a big rethinking or the labor of rewriting the code - version 1.4 already does that. I think the point of this thread is to define a flexible conceptual base that's likely to be more cleanly extensible for a few years of growth.

See above, the proposal adds an additional field and yes, that gives additional flexibility but with the price of one additional byte (or at least field) for every message and additional implementation problems for Controllers on how to represent this.

My question still is how a controller should represent this. Most controllers work with devices that can have one or multiple values. Device can map to node but how to map the remaining fields?

[Zeph]

@daulagari said:

My proposal is basically to merge the ChildSensorId and ChildSensorType into one, being the ChildSensorType, so:

OK. That touches on one of my critiques of the direction it's going. (Maybe "critique" would sound stronger than I intend, I'm not disparaging the current direction, just suggesting another one).

I think that ChildSensorID is an appropriate concept for identification and addressing (ie: included in packets), while "ChildSensorType" is static metadata which should be collected during configuration but does not need to be passed in every packet. So I would simplify in the other direction - get rid of ChildSensorType in the packet addressing heirarchy, rather than getting rid of ChildSensorID.

This idea is not currently popular, in large part I think because the metadata describing a given ChildSensor would have to be collected/stored by each Controller plugin, as the currently favored architecture is to have a very thin gateway node which just passes packets between controller plugins and the OTA packets. My alternative vision would be to have a thicker gateway which could, for example, store the metadata for each ChildSensor (eg: ChildSensorType, but expandable) gathered from nodes during config, and provide it to the controller plugins.

With this approach there is no barrier to having multiple children of the same type (but with different ChildIDs) because the concept of addressing & identity have not been conflated with the ideas of types and metadata. In my preferred alternatives, the normal OTA packet for routine reports and commands omits the semantics and includes only addressing/identity, while the initial configuration passes semantics, types and names that are relatively static and do not change per-packet. Moving ChildSensorType from per-packet addressing to static metadata would be one of the implications of this design principle. (If you apply this to values, then we also include a numeric ValueIndex in the packet and move the ValueType info to the metadata.)

(I went even further and suggested omitting the ChildID from the regular OTA packet by having only NodeID | ValueIndex for addressing, and treating ChildID as static metadata which can be associated with each ValueIndex. Thus for example we could say that ValueIndex 3 contains a temperature value associated with child 2, and ValueIndex 4 contains a humidty value also associated with child 2. The central system (thick gateway or controller plugin) would use saved metadata to know which values come from or go to a given child ID container, but the OTA packet doesn't have to include that every time. Not surprisingly, this was a bit too radical a revamping and has not gained traction. And that's OK too, I'm only one voice with only part of the picture here).

Just to be complete, EncodingFormat (eg: 1, 2, or 4 byte integer or unsigned interger, or 4 byte float, or float encoded a text string etc) could be either config time metadata if it's always the same, or could be included in the OTA packet if it changes dynamically. I can see a case for either design.

I'm mentioning this because you seem interested in looking into deeper changes to the architecture, but I'm not pushing these concepts here now - my ideas on such things have been heard and a few have influenced the direction hek is going, but the overall design concept has not been persuasive enough. That's fair.

The system here is pretty good already, so it's not critical to make such changes. So rather the push MySensor too much, I've been (intermittantly) working on my own protocol ideas (at the spec level) which incorporates these and other concepts, and which could co-exist with MySensors. However my tentative design has additional design goals including high bandwidth distribution of pixel control data and medium high bandwidth collection of rapidly changing "sensor" data (eg: joysticks used for low latency pattern. It would be able to handle the MySensors use case of low bandwidth sensor networking as a less challenging subset. However my design is an off-and-on project on paper so far, while MySensors is a working system, so I give a lot of weight to the latter.

[hek]

Yes, we should set the goals high. But we need a realistic plan using the limited development resources we actually have where people should be able to pitch in when they have some time over between family and work.

I've seen so many Open Source (and workplace) projects die due to grand unrealistic plans where there just isn't enough resources or time to realize them. The key here is doing things in small graspable steps.

So we have a few things to consider and prioritize.

1. Hardware requirements on the gateway. Today we have chosen to keep this as simple as possible but this might change in the future and nothing stops anyone from creating a gateway directly on RPI or ATMega2560 which could handle more advance MQTT stuff ot handle the id-handout.
2. Support for multiple radios. Ongoing work started by @ToSa with a hanging PR (were have you been hanging lately BTW )
3. Keep plugin developers happy with a low threshold to create a plugin. We should keep ourselves from making too large serial protocol changes (too often) or we'll lose many supported controllers along the way.
4. Support more sensor types with examples. This thread is the playground for creating a more complete set of supported sensors. In the spirit of this I've spend the last weeks trying to create more fun examples. The sensor-examples (and controller support) is the key factor to grow a larger audience (and hopefully more developers).
5. Support for thing like encryption and simple OTA firmware updates.

The more people helping out the faster we'll get there.

[Zeph]

@hek said:

Keep plugin developers happy with a low threshold to create a plugin. We should keep ourselves from making too large serial protocol changes (too often) or we'll lose many supported controllers along the way.

I do not mean the following to insist on any changes - I accept that there is a balance to be had between changing things for the future and making today's changes as small as possible, and that somebody has to make that judgement call.

But just to explain where I have been coming from and why I have bothered explaining the alternative approach (clean separation between dynamic addressing/identity and static metadata) - it's because of exactly your point quoted above. If we run into limitations in the architecture a year from now and wish we'd thought it out better, it's going to be a lot harder to fix things because there will be a lot more plugins already written by then. It could be better to bite off that transition now when many HA system interfaces to MySensors are not yet written, and the ones that do exist are still in early development with the original developers highly involved. A year or two from now, more interfaces will exist, and some of the early implementers may have moved on to other foci.

The concrete of decisions will be setting into the stone of legacy code over the next year. Anything substantial that isn't in the next revision of the protocol - being discussed in this thread - is likely to never happen (lots of small tweaks may happen of course). The cusp of going from 95% Vera users with almost all architecture-tied code from a single developer, to a broad array of HA system interfaces written by many groups, is now, and it's going to change the degree of flexibility. This may be the last chance to do a deep rethinking.

The other point was that I was suggesting how to simplify the task of plugin writers, by have a single codebase within the MySensors universe (eg: Arduino C++) for as many of the tasks as possible. That lowers the bar some, and reduces the amount of parallel development of doing the same thing in multiple plugins (like assigning addresses).

OK, I wanted to be understood that my purpose was very much in line with the quoted desiderata, not opposed to it - but I'll be cooperating with the direction @hek chooses.

[ntruchsess]

@Zeph said:

I think that ChildSensorID is an appropriate concept for identification and addressing (ie: included in packets), while "ChildSensorType" is static metadata which should be collected during configuration but does not need to be passed in every packet. So I would simplify in the other direction - get rid of ChildSensorType in the packet addressing heirarchy, rather than getting rid of ChildSensorID.

100% agree. Sending ChildSensorType is just redundant static metadata. Just having implement a MySensor-conroller for fhem I noticed there's no way to request Presentation-messages from Sensors so a Controller after Sensor startup, so the controller has no way to verify it's persistent 'static' metadata without a user going to restart the sensors. This actually is a point that needs to improove.
But the argument a controller would have to be 'thin' (in terms of not being statefull in respect to sensor details) is a no-arg. You cannot do automation without knowing details about the controlled items.

• Norbert

[hek]

Yep ChildSensorType is redundant.
If thin things like the Arduino based MQTT gateway would manage without it we could probably remove it from the normal payload.

Request for metadata is a good idea. Would require sensor to keep this available at all time in memory or eeprom when controller requests it.

[hek]

Update first post to reflect ChildSensorType changes. Should probably rename this thread also.

[ntruchsess]

@hek said:

Request for metadata is a good idea. Would require sensor to keep this available at all time in memory.

This is allready in memory, just requires a move of send-presentation-messages code into own method that is called from begin and in response to 'request-metadata'.

[ntruchsess]

@hek said:

If thin things like the Arduino based MQTT gateway would manage without it we could probably remove it from the normal payload.

As MQTT-protocoll is not stateless (it does Quality-of-service with message-storage and redelivery - though the existing gateway code doesn't support this yet) the MQTT-gateway cannot be a thin thing anyway. I wouldn't mind if it doesn't run on Uno due to memory-constraints, there's the Mega2560 or even the DUE which seems to be affordable as you only need a single gateway per install.

[hek]

First post updated.

[tbowmo]

what about a "RS232" sensor?

The TV in my living room has a serial port to control it (Can do everything I can with the remote) and also request status from the TV (eg. powerstate, channel being watched etc). Could be cool to include that into some kind of domotica solution

/ Thomas

[hek]

This would probably qualify for a special command-type as it's not a "normal" sensor.

Today I've squeezed in scene controller and ir-commands among the "sensors" but they should probably also have their own commands. Thanks for the input!

[Anticimex]

Perhaps rs232 and ir can be fused together as one type? Both are by definition serial protocols. Each with a protocol and symbol rate specific to the appliance at hand.

[hek]

I know too little about rs332 and IR to make a suitable command structure at the moment.

[Anticimex]

Think "uart"

[tbowmo]

Think that, for UART it should be enough to send characters (or strings) to the sensor, and send back replies to the master (If anything comes in at the serial port)

I asume that if one needs to use serial to communicate with some remote device, one will setup baudrate etc. for that particular device in the arduino sketch. So no need to use initialisation commands for the serial stuff.

For IR it's a bit more complicated, because there is no single protocol definition like serial. for IR it could be RC5, RC6, something else, it can be different carrier frequences etc. for each brand. And it can be send to multiple devices, using the same IR "blaster"

/ Thomas

[Anticimex]

@Thomas-Bowman-Mørch well, yes. But I am more thinking a "protocol". No matter what serial interface the sensor has externally, any serial interface implement some form of protocol for managing handshaking, flow control, etc. And considering the limitation in the data packets in RF24, we cannot expect to be able to implement a "stream".
By having a protocol, the sensor node can ensure it collects enough data to be able to satisfy it's external device, i.e. caching data packets for making a larger continuous serial transmission. Or reading a larger continuous transmission and caching it from the device, before starting to transmitting it to the controller. If transmission starts too early, data sent from the device, could be lost (depending on HW/SW solution) as serial protocols do not have to implement flow control (and rarely does).
Both IR and UART share the same caveats so in that respect, I think it makes good sense to figure out a command type that can satisfy both types as the needs are similar. And then it potentially can also be applied to other serial protocols (CAN for instance).

[lunarok]

Hi,

Not very usefull post for you here, but I want to say I'm very pleased to see this discussion and the news I can read here or what appears in dev on the github.

About the presentation of sub-type accepted. After getting an almost complete controller for Jeedom, we have difficulties to "predict" things to automate and make it very simple for user to use the plugin. Like for exemple, create commands. For relays and dimmer it was easy, but after when we look for servo or some extra type it's impossible to know for now what we can create.
So reading, the sensor will tell it in presentation it's just perfect.

Same for the presentation during node of lib used, that's just better than during the sensors, make sense.

I read also on the protocol page, that there is a way for a node to request data from gateway/controller. Can this point be clarified, maybe it needs also the sensor/node to say what it can request ? That's also for automation of autolink. For us (Jeedom plugin) and I think for other, if we know the sensor is able to request some data, we can automaticly create the information item and the user will have only to map it to the equipment it wants to point. I don't know if this is still included/planned as I'm aware many of the "smart" part must be on the controller side, but with beautiful things like Scene Controller and LCD display, I can imagine there is a need ?

I read also the OTA process will change a lot. So, is it better waiting 2.0 to include it on our side ? I mean, for the controller part, will this change a lot of things ?

And last point, there is actually a internal message type Reboot. This one is indicated only working for OTA bootloader. Is that true ?
If so, is it possible in 2.0 to include a way to request a complete presentation of an already started sensor. (that's why I ask for the Reboot message, simpler to request a reboot so the node will present itself at the same type)
Sometimes it's easier when migrating for exemple or reinstall, and we know the ID of sensor to ask it for presentating itself than going there to unplug it.

That's my thoughs after getting a little more in deep of protocol for the controler/plugin

Cédric

[aliasdoc]

Hi, I think we could integrate an uuid system in protocol, like this one https://code.google.com/p/tinkerit/wiki/TrueRandom .

[hek]

@lunarok said:

If so, is it possible in 2.0 to include a way to request a complete presentation of an already started sensor. (that's why I ask for the Reboot message, simpler to request a reboot so the node will present itself at the same type)
Sometimes it's easier when migrating for exemple or reinstall, and we know the ID of sensor to ask it for presentating itself than going there to unplug it.

True, reboot would send presentation again. But another option is to save the presentations in the api. Still a bit unclear which option I will choose.

@aliasdoc
What do you mean the random number should be used for?

[nneeoo]

Hi. I would like my nodes measuring various values (temperature, humidity, ...) to send those values at specific times. I don't want to include the RTC on the node, so would like the node to request a sleep period from the controller. I can see there is no such possibility with the version 1.4 of the protocol. What do you think about including such thing?

[hek]

You can use VAR1-5 for this in 1.4.

2.0 will have both VAR (used mostly for pushing custom data) and CONFIG (for custom node configuration).

[BulldogLowell]

Right now you can use the Time.h library and you don't need an RTC.

Just sync the time with MySensors call...

gw.requestTime(receiveTime);

with the function:

void receiveTime(unsigned long controllerTime) 
{
  Serial.print("Time value received: ");
  Serial.println(controllerTime);
  RTC.set(controllerTime);
}

[nneeoo]

@hek said:

You can use VAR1-5 for this in 1.4.

2.0 will have both VAR (used mostly for pushing custom data) and CONFIG (for custom node configuration).

Yeah, good point. I somehow missed these general purpose variables. It might be good to add a dedicated type for it if you'll find it useful. If not I can live with the VAR for sure ;). Thanks.

[nneeoo]

@BulldogLowell said:

Right now you can use the Time.h library and you don't need an RTC.

Just sync the time with MySensors call...

gw.requestTime(receiveTime);

with the function:

void receiveTime(unsigned long controllerTime) 
{
  Serial.print("Time value received: ");
  Serial.println(controllerTime);
  RTC.set(controllerTime);
}

Thanks for pointing out this library. However I don't want to track the time on the node, but would like just request the time for which the node should sleep from the controller. I think it makes more sense to have the logic in controller.

[BulldogLowell]

@nneeoo

Oh, you are requesting the duration of the sleep... not the moment at which you wish it to sleep.

I thought you were wanting it to transmit data at certain times...

[nneeoo]

@BulldogLowell said:

@nneeoo

Oh, you are requesting the duration of the sleep... not the moment at which you wish it to sleep.

I thought you were wanting it to transmit data at certain times...

Well, yes. I want the node to transmit at certain time. Since the controller should know when that time is, it has to be able to calculate for how long should the node sleep, when the node asks the controller. I hope you get my point.

[BulldogLowell]

@nneeoo

yes, so you can use Henrik's advice and store a variable which is the time interval in seconds, minutes or even milliseconds.

pass that variable into a function that uses that time as the interval to transmit your data from the sensor.

something like this... pseudo code

int intervalFromController; //in minutes

void setup()
{

}

void loop()
{
  gw.begin(getVariables, RADIO_ID, false);
  //your other stuff
  updateSensorData(intervalFromController);
}

void getVariables(const MyMessage &message) //
{
  if (message.sensor == CHILD_ID)
  {
    if (message.type == V_VAR1)
    {
      // get your V_VAR1
    }
  }
}
updateSensorData(int interval)
{
  static unsigned long lastTransmitTime;
  if (millis() - lastTransmitTime >= interval *60000UL)
  {
    //collect and transmit sensor data
   //request sensor interval
  lastTransmitTime += interval * 60000UL;
  }  
}

[ToSa]

@lunarok said:

And last point, there is actually a internal message type Reboot. This one is indicated only working for OTA bootloader. Is that true ?

Reset and OTA bootloader are independent - but you need to set the fuse bits of the MCU to enable the watchdog for the software reset to work. This is done automatically when flashing the OTA bootloader but you can do that as well in a separate step keeping the existing bootloader (e.g. optiboot).

[aliasdoc]

@hek said:

What do you mean the random number should be used for?

I am currently trying to develop a bridge between mysensors and home kit managed with RPi and for this purpose I need an uuid different of the id used in the my sensors library and I thought the above library is a good start for the generation of a uuid (almost unique).

[Zeph]

If there is interest in using somewhat of a standard rather than rolling our own (and I think a case could be made either way), it would be worth reviewing the IoTDB effort which is also trying to describe the semantics of sensor/actuator control. For example:

https://iotdb.org/pub/iot-attribute.html

[hek]

@Zeph said:

https://iotdb.org/pub/iot-attribute.html

Thanks interesting reading.

[daulagari]

Yes, indeed interesting reading also in the light of controllers.

[lunarok]

Hi,

Please to see this post. As our plugin for Jeedom is complet now, I have some feedback to share.
First, is there a date and status of version 2 for now ?

Here my thoughs :

• about units, I agree with the fact that it's lightier to have the Arduino not taking care of it, but instead use some conversion on the controller side

• about value types, it will be better to have really type and not a notion of unit sometime here too like for power get only consuption and not kwh, really going all the way and give the unit control to the controller

• about value types and sensor types, after writing the plugin, still weird for me to have a sensor presentation giving some clue on what type it is, but need to wait for some value to be sure. I mean power sensor for exemple that can get some different type of values, this is not really clean I think. Or the weather sensor, in one case it will send a value type that is numeric, the other one is text (forecast)

• will it not be better to have some mechanism when it's an actuator to deliver the type of message it is accepting ? for exemple a heater, there is the off/on but also a mode type. How is it possible to know that the sensor is accepting all or only on/off ?

So, for me, something like after a presentation being able on the controller to say what type of data and what commands we can say, will be the best. And important too, what data it can be requesting. I mean, now with the scene_controller to extend functions, we need to get data from the automation software too. Imagine to display some informations from outside the mySensors network.
Maybe by completing the sensor_type and merging with value_types, removing the unit notion inside the value. And so during presentation we know all about the data it can send. And in second step during presentation, declare the actuator commands.

One other point important and asked by some users, is it possible to integrate some security in the protocol ? As soon you talk about actuator accepting command from anyone, that's unsecure. Key given during inclusion by gateway and use for encode the data ?

Thanks for reading

Cédric

[Anticimex]

About security, I'm looking into that. I am working on a concept involving key exchange and signing using an external circuit.

[lunarok]

Yes for security can be also a first presentation requiring a signing. Like what Puppet is doing, agents first present themself to the master, master is waiting for someone to accept a request, and after it gives the certificate to the client and then the client tell him verything about itself (facts in this view can be compared to the sketch and sensors presentation)

But I don't know if it's easy with arduino this type of exchange.
Other way can be a simple key we put in sketchs, and using the same on every of our home, and use it in the lib to encode the data.

[Anticimex]

I am working on a security protocol, and have posted my take on things in the security thread. I will weigh in on this thread once I have verified my design, but so far, only two new message types should be needed, one to request security capabilities and once for capabilities and a nonce. I do not think software based security is a suitable solution due to memory constraints so I am going for a hardware based solution with a pre-shared key. I will publish more concrete examples once I have verified them.

[lunarok]

Hi,

Is there any move on the V2 ? Can we see the actual status and what it is going to look like ?
Going to a V2 for the Jeedom controller, will like to see it coming with mySensors v2 changes.
Precisly will like to have a status about :

• reboot of node without needing a special bootloader (inside the lib will be the best)
• sending libversion from presentation including for gateway (this is include for nodes, I don't know for gateway)
• possible of sending V_type used during presentation, no need to wait to send data
• possible of sending a short desc name for each sensors created (can be helpfull when you create many sensors with same type and the difference is not only the order)
• possible to send the power source of node, I don't know inside battery or else. This will be very helpful with battery/plug or battery/solar source for exemple. So we can know how much the battery is full but also if the sensor is actually on battery.
• getConfig to be used for any paramteres instead of units, like this the node can request parameters from the conrtoler (think about a global sketch for a switch that can talk to a relay node, by the controller side you set which node it's controling)

Can we have a wiki page maybe with an actual status of where is the V2 ? And is there a dev version we can try ?

[hek]

@lunarok said:

Hi,

Is there any move on the V2 ? Can we see the actual status and what it is going to look like ?

There has been some delays due to workload. But i hope to finish it eventually.

• reboot of node without needing a special bootloader (inside the lib will be the best)

Not sure it is possible to reboot an arduino without watchdog enabled (anyone knows any tricks?).

• sending libversion from presentation including for gateway (this is include for nodes, I don't know for gateway)

Yep, possible to get version from gateway today.

• possible of sending V_type used during presentation, no need to wait to send data

There will be a different setup.

• possible of sending a short desc name for each sensors created (can be helpfull when you create many sensors with same type and the difference is not only the order)

Good idea! I'll take that into consideration.

• possible to send the power source of node, I don't know inside battery or else. This will be very helpful with battery/plug or battery/solar source for exemple. So we can know how much the battery is full but also if the sensor is actually on battery.

Thats also a good idea. I'll have to think about how it could be incorporated.

• getConfig to be used for any paramteres instead of units, like this the node can request parameters from the conrtoler (think about a global sketch for a switch that can talk to a relay node, by the controller side you set which node it's controling)

Config/settings will be a bit different as well.

Can we have a wiki page maybe with an actual status of where is the V2 ? And is there a dev version we can try ?

Hmm.. my github account (henrikekblad) will contain the source until I feel it's worth trying out by the community. But there is a part of it I'm waiting for a c++ guru at work helping out with (advanced c++ templating which is a bit over my level of c++ knowledge). Those will hopefully make callbacks (incoming messages) usage awesome.

The plan is the gateway will be able to accept/push json objects instead of the semicolon separated parameters, Much depends on how memory demanding it becomes.

[axillent]

can we avoid float?
instead of float a multiplied integer can be used
for example 34.6 C temperature can be presented as 346 (no dot)

a single float operation increase HEX size significantly

@hek what about idea we discussed to have a network with multiple gateways?
what about adding support for the 2.0 for the nodes be able to have a different BASE address per each gateway?
this way the future network will allows to have 255 sensors per EACH gateway, not per NETWORK

[hek]

@axillent

Yes, configurable base address would be handy if we choose to create an ESP-gateway. It is already supported today but you have to hard code it into MyConfig.h. Would be neat to have this configurable over WiFi.

Using OTA transmitted floats is optional. I haven't looked so deeply on how/if this will be supported yet in the upcoming version.

[tekka]

Any plans for encryption?

[Anticimex]

This post is deleted!

[daulagari]

what benefit is there from encryption vs signing in the MySensors case?

If you have a lock or door sensor do you want others to know when it is opened or closed?

Signing is quite expensive if you look at additional payload size, you need a big counter to prevent replay and a big MAC to prevent attacks. I think that when encrypting things you can do it with the same additional payload and maybe even a less.

[Anticimex]

This post is deleted!

[daulagari]

Yes, signing, when properly done, is for sure a good begin.

How many bytes are you using for the truncated MAC and nonce?

The AES block size is 128 bytes, so 16 bytes so I do not see why that would not fit.

Encryption is already some kind of authentication is a sense that if you can successfully decode the message you can be sure that the other side knows the shared secret, just like in the cause of your SHA25-HMAC.

[daulagari]

Would be good to move the last five message into a separate thread...

[Anticimex]

This post is deleted!

[Anticimex]

This post is deleted!

[hek]

I'm afraid I can only fork a topic int two threads. Haven't found a way to move posts to another thread/topic.

[Anticimex]

This post is deleted!

[Anticimex]

@tekka Please see the discussion on security.

[lunarok]

Hi,

A new wish. Possible to have the network gateway listening for nodes also on the ethernet network. Looking for ethernet nodes inside the electric panel. No RF, no security break

[axillent]

A support for multi-gateway setup is needed. Currently it is required to hardcode radio-channel or base-address for different segments-different gateways

[marceloaqno]

There is a solution for multi-gateway that I'm working to port it to the development branch which could use the same radio channel and also to have sensors at gateway node.

[axillent]

@celonunes what kind of a solution it will be?
will it be possible to route messages between nodes managed by different gateways?

[marceloaqno]

Gateway become normal node, with an id(1-254), like a repeater. Address 0 become like a virtual address which is used when a node wants to send a message to the controller.
This solution will give more redundancy to the network but the same limitations apply, like the max of 254 per network.

[marceloaqno]

In the case raised by @lunarok, I'm not sure it will fit.

[axillent]

@celonunes said:

Gateway become normal node, with an id(1-254), like a repeater. Address 0 become like a virtual address which is used when a node wants to send a message to the controller.
This solution will give more redundancy to the network but the same limitations apply, like the max of 254 per network.

OK. But how this will prevent conflicts on the air between nodes connected to different gateways and having same radio channel and BASE_ADDRESS?

[marceloaqno]

Each node will continue to have a unique id in the network.
The controller would have additional work to map nodes to their proper gateway, and this could make the whole idea into something impracticable depending on the controller software.

[axillent]

@celonunes will you keep a limit 8 bit for ID?

currently with multi-gateway setup I have N * 255 address space, where N is a number of gateways

[marceloaqno]

@axillent said:

@celonunes will you keep a limit 8 bit for ID?

currently with multi-gateway setup I have N * 255 address space, where N is a number of gateways

Yes.
Your solution seems interesting, do you have some published code of it?

[axillent]

@celonunes it is not my solution) it is a way of using 1.4.1 with multiple gateways

[marceloaqno]

@axillent said:

@celonunes it is not my solution) it is a way of using 1.4.1 with multiple gateways

I'm aware of this.

@lunarok your wish may become possible in future developments using MQTT