2.0 Discussion: Units, sensor types and protocol

[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?