Best non-WiFi wireless module for big home applications.

Hi!
I'm going to make a project that measures the temperatures in some points of my house. I think about five atmega328 on a breadboard that read a DHT22 sensor and transmits the value to a central Arduino that can display the values on a monitor. The problem is, how can I transmit the value? My house is quite big (two floors, many rooms) and I don't want to spend more that 5€ in each transmitter module. Any suggestion? I see the NRF24L01+PA+LNA Wireless Module in my research. Is it good also indoor? It's hard to program or it has some library to interact with it?
Many thanks!

This Simple nRF24L01+ Tutorial may be a useful starting point. The ackPayload example can be extended to operate with several slaves.

I suggest that you get a couple of the cheap nRF24L01+ modules with the PCB antennas and do some experiments in the actual locations you are planning to use.

I have no experience of the high power nRF24s with the external antenna but I think it would be worth considering the possibility that one of them is only required for the master unit.

I also suggest locating the master unit in the best place for the wireless system. The principal calculations and display of data to the user does not have to happen on the Arduino connected to the wireless master.

...R

If you have wifi in your mansion, just some ESP8266's with DHT22's slapped on them will be a cakewalk.

INTP:
If you have wifi in your mansion, just some ESP8266's with DHT22's slapped on them will be a cakewalk.

Yes, but I have no wifi in that house, so I must use an alternative wireless solution.

Responding to Robin2:

I have no experience of the high power nRF24s with the external antenna but I think it would be worth considering the possibility that one of them is only required for the master unit

I read that the PCB antenna is terrible, over 30 meters the signal go down in outdoor testing. Have you experience with the PCB antenna one? Is so bad over 3/4 wall?

The PCB antenna was working for me over 110m outdoors and would probably have worked at a greater distance but I could no longer see my test device.

They are not expensive. Get some and do some tests. Or just get the more expensive high powered ones if you prefer.

This is not a project you can design without some test data.

…R

wifi not needed for esp8266s?

Maybe something like the Moteino with a RFM69/RFM69HW transceiver on board? The 443MHz signal (compared to the 2.4GHz of the ESP & nRF) should have better penetrating power through walls and floors and if you stump up the extra for the flash memory you can also program them over the air.

DaveEvans:
wifi not needed for esp8266s?

I look some links of the google page that you post but in all the tutorial I need a wifi connection.

Robin2:
The PCB antenna was working for me over 110m outdoors and would probably have worked at a greater distance but I could no longer see my test device.

They are not expensive. Get some and do some tests. Or just get the more expensive high powered ones if you prefer.

This is not a project you can design without some test data.

...R

I find two version, a black one and a green one, and I find on the internet that the green is more powerful that the black one. Is it true?

Riva:
Maybe something like the Moteino with a RFM69/RFM69HW transceiver on board? The 443MHz signal (compared to the 2.4GHz of the ESP & nRF) should have better penetrating power through walls and floors and if you stump up the extra for the flash memory you can also program them over the air.

Is not the opposite? That the 2.4GH is more powerful in long distance that the 443MHz (Mainly because they are less affected by disturbances on the signals)?

Thanks to all!

Eternyt:
I look some links of the google page that you post but in all the tutorial I need a wifi connection.

This one doesn't (first hit)

Your Black and Green links come up as Access Denied.

Lower frequencies are better for longer ranges. But the nRF24 modules have a lot of helpful features including error checking and automatic retries.

…R

The ESP8266 has higher transmission power (and range) than the NRF24L01. If your building has concrete walls and floors you will not be able to use anything in the 2.4GHz range (WiFi, Bluetooth, NRF24L01). LoRa could be the way to go, or any other lower frequency radio for that matter.
I am working on a project to make wireless monitoring a lot easiert, it is called 'Lambda Nodes' and I will open a thread about it shortly. If the project gets enough feedback I will start a crowdfunding to have the PCBs manufactured by Seeedstudio. You can check out my webpage for a short introduction:

Lambda Nodes

DedeHai:
If your building has concrete walls and floors you will not be able to use anything in the 2.4GHz range (WiFi, Bluetooth, NRF24L01).

Do you specifically mean concrete (rather than brick, for example).

I have had an nRF24 (with PCB antennas) working from another room in a brick-built building.

...R

Robin2:
Do you specifically mean concrete (rather than brick, for example).

I have had an nRF24 (with PCB antennas) working from another room in a brick-built building.

...R

yes, concrete is the worst especially when walls are thick. Brick is a lot better and plaster or wood is best for transmission range. I successfully tested the Lambda Nodes (NRF24L01) at a distance of about 50m inside an office building through 3 plaster walls. When testing in my flat with concrete walls it only can make it through one wall.

+1 RFM69

A few options ready to use in the Market:

ATMega328p, 4Mbits Flash, Runs on a single AA: Whisper Node - AVR - Wisen
ATMega328p, RTC: Anarduino MiniWireless Details
ARM Controller: http://www.rocketscream.com/blog/product/mini-ultra-pro-with-radio/

Robin2:
Lower frequencies are better for longer ranges. But the nRF24 modules have a lot of helpful features including error checking and automatic retries.

FYI the RFM69 libraries used on the Moteino are similar to the nRF24l01+ libraries in that you set address/node number, can retry sends, ack receives. It has potential benefits in hardware AES encryption, 61 byte message length, adjustable TX power.

I've implemented a similar project, using 6 temperature sensors inside and outside my house,
transmitting data wirelessly back to a central receiver.
The transmitters are "breadboard" ATmega328P (using the internal 8MHz clock) with a DHT22 sensor attached.
The receiver is an Arduino.

I'm using 433 MHz ASK modules for the wireless communication. These are simple, cheap and low power
which is needed as the transmitters are battery powered. The software is the ASK driver from the RadioHead library.

Sending one reading every two minutes, the transmitters get two years (so far!) of life out of one set of 3xAA batteries.
The MCU is put into a deep sleep mode between transmissions in order to conserve power.

The longest transmission distance is about 35m through four internal walls.
The error rate is negligible, about 1 message in 2000 is lost or corrupted.
The key factors in getting reliable transmissions were:

  1. The aerial - I use a 17cm vertical wire on the transmitters and receiver
  2. A good quality ASK receiver module, preferably a superheterodyne type. I use an LR45B.
  3. Transmit each message at least twice with a random delay to compensate for possible collisions.
  4. Keep the message as short as possible. Make sure every bit earns its keep. Mine are 8 bytes long,
    which includes a signature byte, code version, transmitter ID, message number, retry number, temperature, battery voltage,
    and DHT22 error rate. Also I use the 4 byte transmission header (txHeaderTo etc) for data as the ASK driver doesn't use it.
  5. Use a low transmission speed - I use 1200 baud.

DedeHai:
yes, concrete is the worst especially when walls are thick.

Interesting. Thanks.

...R

Robin2:
Your Black and Green links come up as Access Denied.

…R

Try this: black and green

DedeHai:
The ESP8266 has higher transmission power (and range) than the NRF24L01. If your building has concrete walls and floors you will not be able to use anything in the 2.4GHz range (WiFi, Bluetooth, NRF24L01). LoRa could be the way to go or any other lower frequency radio for that matter.
I am working on a project to make wireless monitoring a lot easier, it is called ‘Lambda Nodes’ and I will open a thread about it shortly. If the project gets enough feedback I will start a crowdfunding to have the PCBs manufactured by Seeedstudio. You can check out my web page for a short introduction:

Lambda Nodes

Sounds great! I saw the website and I find it a very good idea. If you have any update, tell me, please!

dreamweaver2:
I’ve implemented a similar project, using 6 temperature sensors inside and outside my house,
transmitting data wirelessly back to a central receiver.
The transmitters are “breadboard” ATmega328P (using the internal 8MHz clock) with a DHT22 sensor attached.
The receiver is an Arduino.

I’m using 433 MHz ASK modules for the wireless communication. These are simple, cheap and low power
which is needed as the transmitters are battery powered. The software is the ASK driver from the RadioHead library.

Thanks a lot for posting dreamweaver2! It looks like what I’m going to do, or something really similar! Can you share with me your code so I can understand how you wake up every x minutes your Arduino and how you communicate with the central Arduino and some other questions that I have!

Thanks to all!

UPDATE:
I attach two images because the links seem doesn’t work.

Screen Shot 2016-10-21 at 18.37.53.png

Screen Shot 2016-10-21 at 18.37.58.png

Eternyt:
Try this: black and green

Same problem. I presume you have signed up and I am outsider.

...R

Also recognize that some of the goofiest things in the house will block line of sight energy from things. Things like the big mirror in the bathroom - that is silver on the back of the mirror and it makes a wonderful block to signals it is between. Foil faced insulation around the outside of the house is another one that can cause lots of problems if it is somehow in the middle of the signal path (as can things like the metal lath in a stucco wall for example) or metal lath if used for a tile floor backing for example can block the signal between floors.

mikey