Your help is needed - question regarding rules and variables

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Hi pimatic team,

I would need your help regarding rules and variables. My pimatic system is running now for quite a while.
My main use case is the automation of a habitat in a terrarium for my Vietnamese leaf turtle.

Please find below my active rules:

I would like to discuss with you two important topics for me:

1. Error reading DS18B20Sensor with hardwareId XXXXX: ENOENT: no such file or directory, open ‘/sys/bus/w1/devices/XXXX/w1_slave’

I´m getting this error sporadically and I can´t reproduce it. Sometimes the sensors (3) are working well for more than a week and sometimes this error message appears after an hour. Is this a known issue?

2. I´m trying to implement a sprinkler automation but i´m struggling with the rules

Important: The sprinkler can only run for 2 minutes due to hardware limitations. After being on for 2 minutes there must be a break for 1 minute.

My goal is to read the humidity in vietnam - compare it with local humidity in the terrarium and then start the rule to reach the same humidity level.

The humidity in vietnam is read every 15 minutes. I´m using a DHT22 for local humidity in the terrarium.
I build a variable device that subtracts the variable for humidity in vietnam against the dht humidity:

Please find below my variables:

Let me know if you need anything else or if you have further questions.

BR,
André

Just a short response to your question.

1. The sporadical error shouldn’t be a problem if you sample the temperature frequently enough (like every 1-3 minutes) In that case missing some samples isn’t a problem.
   I assume your checked the wiring, etc. The DS18B20 plugin is an older one and maintained by @mwittig (at least he did some maintenance last year).

2. Using a sprinkler to increase the humidy is nice. Do you have any info on what the increase of the humidity is related to the time the spinklers are on? And what the delay is between switching on and switching off the spinklers and the humidity value?
   You need that info to make rules that will not over/undershoot the actual humidity.
   With that info, the rules and variables for controlling the humidity isn’t difficult.

@bertreb said in Your help is needed - question regarding rules and variables:

Just a short response to your question.

1. The sporadical error shouldn’t be a problem if you sample the temperature frequently enough (like every 1-3 minutes) In that case missing some samples isn’t a problem.
   I assume your checked the wiring, etc. The DS18B20 plugin is an older one and maintained by @mwittig (at least he did some maintenance last year).

2. Using a sprinkler to increase the humidy is nice. Do you have any info on what the increase of the humidity is related to the time the spinklers are on? And what the delay is between switching on and switching off the spinklers and the humidity value?
   You need that info to make rules that will not over/undershoot the actual humidity.
   With that info, the rules and variables for controlling the humidity isn’t difficult.

Thanks for your fast reply! I will answer directly to your questions:

1. The problem is that if this error occur the sensors wont show any data for a longer time *sometimes until the next restart of pimatic and sometimes nothing helps and i wont have data for days.

2. This is a really good one… I dont have any data related to the time the sprinkler is on. The idea is that the "dht_humidity variable should approach the vietnam humidity in small steps.

Argh that´s difficult for me to explain. But I do understand why you are asking these questions and they make completely sense.

BR,
André

1. a longer time no data is not good.
   The error message is about the operating system losing that device. And it seems that sensor1 is missing. Can you try to use 1 or 2 temp sensors and to exclude (disconnect) sensor 1?

2. If you assume the humidity sensor is as fast follower of the humidity increase, i could give you some rules.
   The DHT22 respond in approx 6-10 seconds to a humidity change, if there’s enough air flowing thru the sensor. Thats seems fast enough.

1. I just restarted the DS18B20 plugin and there they are again after being not available for one day…
   Lets wait two hours and i´m sure we will see the same error message again.

2. I would say that the humidity will increase quite fast after activating the sprinkler. The most important point is that the spinkler does not run longer than 2 minutes and it needs at least 1 minute break.

BR,
André

if you switch on the sprinkler for only 20 seconds, do you still have to wait 1 minute?

@bertreb said in Your help is needed - question regarding rules and variables:

if you switch on the sprinkler for only 20 seconds, do you still have to wait 1 minute?

I´m not sure and this is not defined in the technical specifications but I would say yes. Lets stay on the safe side and wait after every activation for 1 minute

so the rule flow could be

while $humidity-diff > 0
  regenanlage on
  wait 1 minute (shorter than max, to prevent humidity overshoot)
  regenanlage off
  wait 1 minute (waiting time of sprinkler)
  $humm-diff = new value

If you agree, i can translated it into rules, variables and 2 timers

@bertreb Thanks for your help so far! I would like to give it a try

My suggestion for the vietnamse-turtle-humidity-controller

Create a variable called ‘sprinkler-state’ with value 0 and create a timer device called 'sprinkler-timer’
Create the following 3 rules:

• rule 1
  when: $sprinkler-state is 0 and $humidity-diff > 0
  then: stop sprinkler-timer and reset sprinkler-timer and start sprinkler-timer and turn regenanlage on and $sprinkler-state = 1
• rule 2
  when: $sprinkler-state is 1 and $sprinkler-timer.time > 60
  then: turn regenanlage off and stop sprinkler-timer and reset sprinkler-timer and start sprinkler-timer and $sprinkler-state = 2
• rule 3
  when: $sprinkler-state is 2 and $sprinkler-timer.time > 60
  then: stop sprinkler-timer and reset sprinkler-timer and $sprinkler-state = 0

The stop, reset, start sequence of the timer is to be sure (there are/were some issues with timers not resetting). I turn the sprinklers on for 60 seconds, but you can increase that to max of 120

Let me know if it works and you can tweak the values as you like.

@bertreb Thanks for your time and fantastic support!
It worked out well in my simulation. Go live will be tonight as the DHT sensor is not wired yet.

Regarding my DS18B20 sensor: I activated a manual interval of 2 minutes for every request.
Before it was at 10 seconds and thats not necessary and this could have caused the issues.

Could you guys help me out with another problem? I´m sure that this one will not be easy to solve but lets see…

As you can see in my initial post i´m pulling live weather data from openweather plugin using a “OpenWeatherDevice”. The city is Hanoi in Vietnam: https://openweathermap.org/find?q=hanoi

The local time in hanoi is 22:04 Friday, 24. Januar 2020 (GMT+7) and this means that the humidity level is not correct for my automation. We are now applying with the new rules from @bertreb the realtime humidity level from 10 PM (local time vietnam) but it should be the humidity level from 7 hours (GMT+7) in the past.

I had this discussion two years ago with @SaxnPaule and some other guys

BR,
André

@bertreb said in Your help is needed - question regarding rules and variables:

If you assume the humidity sensor is as fast follower of the humidity increase, i could give you some rules.
The DHT22 respond in approx 6-10 seconds to a humidity change, if there’s enough air flowing thru the sensor. Thats seems fast enough.

just to understand you correctly. You want every 15 minute the ‘actual’ humidity for Hanoi like it was 7 hours earlier?

Yes, I think thats right, but could also be that im totally confused ^^
I cant remember well but we need the 15 minutes because of the api limitations from openweather.

Querying once per 15 minutes seems logical. The humidity changes not that fast.
But getting now the humidity of 7 hours earlier is the challenge.

This is the last missing piece to complete my goal of a almost 100% automation.
I dont know if there is a solution but if there is one, then we need to apply it also for the temperature.

BR,
André

the solution is to buffer the 15 minutes humidity values for 7 hours and read the oldest value out of this fifo buffer.
With ‘only’ rules and variables available this is difficult. In coffee or javascript this is easy.
I could write a small swiss-knife pimatic plugin to support this as a first tool.

This Sounds like a plan. Let’s give it a try
And thanks again for your time and help!

@Andre3000 I released a first version of the pimatic-tools plugin.
It has 1 device type called VariableDelayDevice. You can imagine what its for.
It can be installed via the plugin page (browse tab).
The readme should explain how to use it.
Let me know what the results are and if anything should change.
I’m also testing it, but because of the delay it takes some time

@bertreb Thanks again for your time and help!
The installation of the plugin was easily possible without any issues.

I´m still testing the plugin and I will come back to you as soon as possible.
BR,
André

@bertreb I´m not sure if the plugin is working as intended. The variable is sampled every 15 minutes but the value is not changing. It stays at the same value as 7h before.

Could you double check with your environment?
Br,
André