Civil engineer student from Belgium wants to start a home automatistation projec

Hello, I am a belgian final year student Civil Engineer-Architect (Master in building techniques)

I would like to develop an home automation system, but do not know if I best work with Arduino, Raspberry Pi, or rather another system like z-wave, nest,….

Anyhow I want my input to be efficient so I’ll need many sensors, and the z-wave sensors for this are far too expensive, via arduino I could use cheaper sensors, and in principle the thing I want to do is 'if this happens, then that action happen' principle, which is should be perfect for an Arduino no?

I’ll eplain a bit more my case I want to focus on: With our insulation requirements for the government here in Europe becoming more and more killing for a good architectural design, I want some more freedom, the calculation of heat loss is always based on static data, I was thinking to start a little project to reduce the heat loss in a home through automation. I would like therefore this applied to my own apartment. I attached a small example of how the input should look like

For example: Motion sensor can record the pattern of occupant and we can obtain optimum operation of the heater with these values. The system registers that on a business day the last person leaves the house at 8:30 am every morning, and the first person returns home on Mon / Tue / Thu / Fri at 17h, Wednesday at 16h.

The same principle with humidity sensors and humidity in bathrooms or air quality.

For output then we could get:

The heating can therefore be off 80% of the day, and must be set to x degrees when the first person returns home. Sensor detects that the last person goes to sleep 22h30, so 21h45 the heating may be switched off until morning.

When the last person has left in the morning, the heating shuts off again, and windows may be opened by an automated rod so that fresh air can enter, without the heater still turned on, and therefore no heat is lost.

If somewhere here in the forum or anywhere else has already written such a small project is, do not hesitate to share this moment here with me to let me go start. This is a big issue here in Europe and it would be great if we could find good programmable options to solve these problems.

Thanks for your answer! Mvg Jonas

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I would like to develop an home automation system, but do not know if I best work with Arduino, Raspberry Pi, or rather another system like z-wave, nest,….

The Arduino should be fine. You may need to add some “extras” such as a real-time clock module, and perhaps an LCD display or Wi-Fi shield, etc.

I’ve never used the Raspberry Pi, but I think the Arduino is better for “simple hardware”, such as reading a button/switch and turning on an LED or relay.

If you want something with a “computer interface” (USB, etc,) the Raspberry Pi is probably better.

Anyhow I want my input to be efficient so I’ll need many sensors, and the z-wave sensors for this are far too expensive…

I always recommend that you make your system compatible with one of the existing home automation standards (X-10, Z-wave, Insteon, etc.).

With something compatible, you can more-easily expand later, and if you want to control lights & power outlets there are several “engineering challenges” (such as electrical isolation and providing low-voltage power to the local electronics) that have already been taken care of in a pre-made unit. (Heating & air conditioning is controlled by low-voltage relays, so the engineering isn’t quite as tricky.)

You may want to build part of the system yourself, and buy some pre-made components. You might be surprised how the costs add-up when building something yourself. The electronic components are cheap (except for the Arduino), but when you add a power supply, connectors, and a housing, and maybe an LCD display, etc., it’s often cheaper to buy something pre-made (if it exists).

I think you would find it much easier to do the "intelligence" programming in Python on an RPi (or on a Laptop) and just use the Arduino to interface between the RPi and the sensors.

...R

Robin2: I think you would find it much easier to do the "intelligence" programming in Python on an RPi (or on a Laptop) and just use the Arduino to interface between the RPi and the sensors.

...R

That's probably true, i only programmed with arduino so far but Python can't be that hard to learn i guess, I'll look into it :)

DVDdoug: The Arduino should be fine. You may need to add some "extras" such as a real-time clock module, and perhaps an LCD display or Wi-Fi shield, etc.

I've never used the Raspberry Pi, but I think the Arduino is better for "simple hardware", such as reading a button/switch and turning on an LED or relay.

If you want something with a "computer interface" (USB, etc,) the Raspberry Pi is probably better.

I always recommend that you make your system compatible with one of the existing home automation standards (X-10, Z-wave, Insteon, etc.).

I think that's ideal too, but their profit on 1 sensor is just soo insanelyhigh, they produce them in china and multiply the price by 10, i can buy easily 6 mediocre sensors for the price of one.

So maybe I'll need to find a way to use an arduino/raspberry to translate the input signals of my cheap sensors to a comprehensible signal to interfere with a normal, central hub from an expensive company like Z-wave, X10...

Is there one system in particular that's more easy to combine with cheaper sensor inputs?

When it comes to sensors, I have two suggestions.

  1. For motion sensing, buy the little door-opener Doppler radar units. They transmit a very weak 10 GHz signal, and when something within range (reliably, about 20 feet), moves, it is detected by a beat frequency output, generally between say 5 and 20 hertz.

You can buy these already built up to put out a 5 v. square wave, but those are about $30 U.S. I buy the raw ones (which put out a few millivolt sine wave), because you can find on-line a circuit for an amplifier/filter for these, which you can build for about $1.00.

I've used these for a long time, and I've never had a false alarm, or a missed real event so far as I know. I turn the amplified output into a square wave, route it to an interrupt pin, and time how long it takes to receive 20 pulses.

  1. For temperature sensing, consider thermistors, which are effectively temperature-controlled resistors. They are dirt cheap, and very accurate. You only need to familiarize yourself with the Steinhardt-Hart Equation to convert their variable resistance to a temperature.

jrdoner: When it comes to sensors, I have two suggestions.

  1. For motion sensing, buy the little door-opener Doppler radar units. They transmit a very weak 10 GHz signal, and when something within range (reliably, about 20 feet), moves, it is detected by a beat frequency output, generally between say 5 and 20 hertz.

You can buy these already built up to put out a 5 v. square wave, but those are about $30 U.S. I buy the raw ones (which put out a few millivolt sine wave), because you can find on-line a circuit for an amplifier/filter for these, which you can build for about $1.00.

I've used these for a long time, and I've never had a false alarm, or a missed real event so far as I know. I turn the amplified output into a square wave, route it to an interrupt pin, and time how long it takes to receive 20 pulses.

  1. For temperature sensing, consider thermistors, which are effectively temperature-controlled resistors. They are dirt cheap, and very accurate. You only need to familiarize yourself with the Steinhardt-Hart Equation to convert their variable resistance to a temperature.

And are they compatible with an existing system, maybe an open-source one, like DVDoug suggested?

jrdoner: For temperature sensing, consider thermistors, which are effectively temperature-controlled resistors. They are dirt cheap, and very accurate.

For a digital system?

Use a DS18B20 that is designed for the (digital) job. You just connect it to the Arduino and use the corresponding library. No calibration, no fiddling about with other components.

Note that it must be close to the Arduino module, but that is actually no different to the thermistor.

Your big problem will be the wiring to communicate between the Arduino units (generally Pro Minis) You could use the "Internet Of Things thing" - the ESP8266 instead of the Arduino, but I consider reliable communication more important.