Hello,
I'm running a few high power LEDs that generate some heat which over time will become too warm (even the heatsink). I've mounted a BME280 and AM2302 to get temperature readings close enough the heatsink.
Is it possible, with automation to activate a relay to start two fans to run if temperature is over 40deg C (the reading from the sensor) and disable it when it cooled the heatsinks to < 30 deg C?
If not, how can I activate the relay if its over 40 degrees and run it for 30 minutes and evaluate the reading again over time?
I'm running this with the irrigation hat I got from tindie as info.
Thanks for a really cool project!
/Carl
Hello,
it is possible to use the automation function for your purpose.
The function will read the sensor every N minutes, depending on your setup and evaluate an action according to the automation setting.
First suggestion is to reduce the sensor reading interval to 1 minute.
You can go to the hardwaresetting page, click edit table, select the sensor and in the "time" field put the string 00:01:00. Then click "confirm and save".
The automation page has quite many settings, it's a bit complicate but it's quite flexible.
With above setting sensor setting, the system will now evaluate the action every 1 minute.
As in below example, If the temperature is above 40, it activates the relay for X minutes (600sec = 10 min), then every minute it will check the temperature, if it is above 40 will again activate for 10 minutes, but as the relay was already activated, it will just extend the activation of 1 min.
In case you want the system to activate for 10 minutes and then wait for M minutes before activating again you can set the "pause between activation" field.
Here an example of the configuration:
Thank you for the reply.
Will study the suggested section.
I am unable to purchase your automation hat as I am in India. What alternative do I have?
hello,
for the question 1) you can find instructions in the following link:
You can look at the section: "Hydrosys4 configuration (For input)"
The new row in the Hardwaresetting table will create a "sensor object" which you can use in the hydrosys4 SW functions.
for the question 2) I suggest the GPIO that I use in the AutomationHat, which are the following: GPIO 5,6,12,13.
I am having 2 issues...
I am sending the sensor data over wireless using MQTT so I don't know how to make this work in that scenario.
How to decide which GPIO pin to use to connect a general purpose 4 relay board to the RPI for the relay activation.
Guidance will be much appreciated!
Thank you!!!
The END value, normally indicates a limit that you do not want to overcome. If I remember correctly it will send you a warning mail and a system message if this value+"1 step interval" is passed. The "one step interval" is calculate as the (END-BEGIN)/(Numebr of Steps). In this case, the warning will be sent at 50+10 = 60 degrees.
This type of warning was very useful especially for the temperature control of my greenhouse.
In case the END value is lower than the BEGIN value, the algorithm will activate in reverse, this is necessary in case you require to activate a heater and you do not want the temperature to go below a certain threshold.
Thank you! Works great!
In this case, what does the END value do?