Yes, metal are trouble makers.... Some constructions that use concrete with iron mesh for reinforcement are like the worst.
But saying that I got a RFM69 inside the fridge and 30 away from the base station and it's all good... Can see some significant signal strength reduction when closing the door but the signal still goes through the metal box.
Also, similar to the mirror, windows with tinted film to block sun can have a similar effect. Easy to notice ia a car when trying to use GPS with all windows closed.
Robin2:
Same problem. I presume you have signed up and I am outsider.
I update the previous post adding two images of the two types of transmitter.
I made some research and I found that my walls are made of brick. So, what module is better to use to send a signal that goes through 1/2 wall? So, definitively, it's better to use an nRF24L01 transmitter or an RF one? And if RF, what is the best module that I should buy?
Eternyt:
I update the previous post adding two images of the two types of transmitter.
Images are generally no good for determining differences. You need to post links to the datasheets.
One of the images has "NRF24L01" printed on it. There is a significant difference between the obsolete ..L01 and the newer ..L01+ modules. Make sure you get the + version.
I made some research and I found that my walls are made of brick. So, what module is better to use to send a signal that goes through 1/2 wall? So, definitively, it's better to use an nRF24L01 transmitter or an RF one? And if RF, what is the best module that I should buy?
An nRF24 is and RF transmitter.
Back in Reply #1 I suggested getting two nRF24s and doing some experiments. That is still my advice.
Eternyt:
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!
Hi Eternyt,
Attached are the RF transmitter and receiver sketches. The sleep routine comes from Nick Gammon's excellent website.
There are other components to the complete project, principally the sketch which initialises the EEPROM values of the transmitters, and a Raspberry Pi which gets the temperature readings from the receiver Arduino via I2C and then uploads them to an IoT channel.
For choosing a transmitter to get a signal through thick walls, the power rating is an important factor. You would want at least 20mW, and I have seen them available up to 100mW though your local authorities may place restrictions on signal strength in the 433 MHz band.
Robin2:
Images are generally no good for determining differences. You need to post links to the datasheets.
One of the images has "NRF24L01" printed on it. There is a significant difference between the obsolete ..L01 and the newer ..L01+ modules. Make sure you get the + version.
An nRF24 is and RF transmitter.
...R
I know that datasheet is always the best option, but I don't find a datasheet for the green version so I try to upload the two images and see if someone that have both can give me some advice.
I didn't pay so much attention to the +, but I found this article that says that the green one is much better (also in the comment there are people saying this). So, what is better to buy?
Thanks a lot dreamweaver2! I hope that your code can help me!
Only one other thing, I decided to buy both the nRF24L01+ and a low frequencies RF transmitter (like the 443 MHz), and for the low frequencies RF, what is the best module for an indoor usage (go through 1/2 wall made with brick)?
I finally got around to open a new thread about my Lambda Nodes project, it uses the NRF24L01 module. Please see here Introducing Lambda Nodes
I also shot a demo video, link in the new thread.
