Advice: Whole Home Radiator Fan/Temperature Controller

[Syna]

Hello all,

This is my first major project with the Pi and was looking for some advice.

I have been reading up on this now for over a week, and I am swimming in thoughts and ideas.

The Brief:

I am looking to create a simple and cheap home radiator fan to assist with a standard convection radiator (the radiators in our house are quite small to the room sizes). Ultimately this will form the bones of an extended integrated Home Automation project, but my thoughts are that this start would be easily transferable to garden sprinklers, front drive gate, integration with Wisebox lighting control and perhaps underfloor heating Controller.

For now

Each control unit at each radiator will have three temperature sensors
1. Temperature of the Radiator
2. Temperature of air input (i.e room temperature)
3. Temperature of air output

and also the ability to switch on and off 12v fans (2no) to drive the air over the radiators when sensor 1 detects that the radiators are on and the air temperature at sensor 3 is below a defined threshold.

Each unit will be powered from a single 12v supply, and so will need to be stepped down to 5v for the Pi.

Each unit will report the temperature of thermometers for data logging and graphing live (preferably not reliant on web based server but local) via a local Web Page.

Longer term development:
- Control through Homebridge,
- integration with a Thermostatic Radiator Valve Actuator (12/24v) http://www.heatingsave.co.uk/product/th ... 24v-ac-dc/
- communication back to Nest (or other) thermostat to "call" for heat
- integration with underfloor heating control

The solution so far for the prototype:

fullsizeoutput_e77.jpeg (183.48 KiB) Viewed 838 times

Temperature Sensor:
- Pi Zero W for control and recording temperature
- 12v supply
- 12v to 5v converter https://www.amazon.co.uk/Regulator-Volt ... +12v&psc=1
- 3 x Temperature Sensor (DS18B20)
- 1 x 4.7k Ohm Resistor for temperature sensor
- 2 x 12v Fans
- 2 ch Relay module https://www.amazon.co.uk/Eeenjoy-Channe ... +2+channel

Central recorded / Web interface:
- Rasberry Pi - Needs help

Sofware and setup:
Needs help


I have been looking at quite a few projects that have some parallels with this, but not found anything that brings all the elements together.
https://www.raspberrypi-spy.co.uk/2017/ ... pi-zero-w/
http://www.instructables.com/id/Raspber ... ontroller/
http://www.instructables.com/id/HomeKit ... -No/#step1
http://projects.privateeyepi.com/home/temperature-gauge


Any advice is much appreciated.

Thanks
Syna

[Davies]

be careful with the 12-5v converter as the variable type can be totally under amp, the 1.5amp they have advertised may not be continuous and it could be rated with a 35v input not 12v, at 12v input you could be sub-optimal 200mA or so, i tend to look at car usb accessories when converting 12v to 5v as they are cheap and specific for the voltages.

personally id develop it in python, you could have a web interface using web.py and all the interaction you wanted.
if you wanted to go for python it could be worth breaking everything down into smaller digestible chunks then merge them together when ur happy with each part.

here they get a ds18b20 to display its temperature
http://www.circuitbasics.com/raspberry- ... -tutorial/

here is a fan turned on/off based from the raspberry cpu temperature, but could be modified to use the ds18b20 temperature
http://www.instructables.com/id/Automat ... an-for-Pi/

once you get that working you could then give it a html front page using web.py
http://webpy.org/docs/0.3/tutorial

if you wanted something better looking than a blank html with writing you could use a website template from w3schools (which are free for all)
https://www.w3schools.com/w3css/w3css_templates.asp

python is an awesome language with lots of support available, if you check the links and they seem somewhat daunting check out how to turn on LED in python on youtube https://www.youtube.com/watch?v=J9cEAGTLaC8 then research your way from there.

also the relay module you have will need 5v to jd-vcc, 3.3v to vcc and both grounds will need to be used, also when you send the gpio high 3.3v (to turn on an LED) your relay module will turn off and the gpio low 0v (LED off) will turn the relay module on due to the relay modules circuitry.