Need help with a rule speed controll

Developer Programs Rules API
1

i have a pwm fan controlled by mqtt fan (thanks to @TAustin ) speed being 100- 1000 ,and a ds18b20 conected to my pi showing in smartthings via a mqtt temperature sensor .
i want to controll the temperature of my 3d printer enclosure ,
i want to maintain a temperature of about 28.5C
i want a rule to automatically turn the fan on 28.5 @ 100
and if it goes above 28.5C i want the fan speed to increase upto the full 1000 at the top temperature of 30C.
the only rules i have so far are copied and pasted as they are beyond me
so any help would be much apreciated.
thanks
martin

2

Do you mean Rules API rule?

Is it more easy to make Python program to RPi
and control the fan speed directly from RPi using MQTT?

2 Likes
3

yes rules api rule ,
the pi controlling the fan speed via mqtt would that be easier?

thanks
martin

4

I think it would be easier.

Every time RPi received a new temperature measurement value, it could send speed control to the fan.

5

doesnt sound easier to me lol,
how would i go about doing that.
thanks
martin

6

Do you use a Python program to send measurements to the MQTT broker?

We can use DM if you like.

7

i use node red to read the gpio and send it via mosquitto.
whats DM

8

Ok
I haven’t used node red.

9

i found this but it reads cpu temp not from sensor
FanProportional.py

10

tried it on a spare pi zero w and it works well but only from cpu temperature

11

I DM to you example Python program to read 1-wire sensor (18B20)

12

I installed Node-RED to my RPi.

You can use temperature to fan speed scaling Node-RED range function.

Node-RED_range_1

Node-RED_range_3
Node-RED_range_3750×703 29.5 KB

1 Like
13

thanks works great , im new at node red as you can tell.
martin

1 Like