Introductions and Range Issues

titvs

Hi everyone,

I've discovered the My Sensors project a couple of months ago and decided to get to work and start to automate my house. It's a very nice colaborative project so i hope to also help. I have reasonable knowledge of electronics, electricity and Arduino programming, so finding MySensors was a great find.
So, i got to work and started building temperature + humidity nodes based on Arduino Nano and NRF24 radio modules. Did a trial run with one node and a LAN Uno Gateway and it worked.
Since i have a 3D printer i designed these little boxes for the nodes and added to them a little 0.96" OLED display, so you can see the values when you enter the room where the node is located:

Everything is in place without fasteners (except for the back plate) and the radio module is at the top of the box, on an horizontal position. At the back i added a custom power connector based on jumper pins, where you can connect the power to a secondary module (i hope i can add to it a module to control my air conditioning).
I then installed Domoticz on an Intel NUC running W10 and attached to it a serial gateway via USB (running on an Uno). I started to place my nodes but alas, im running into the usual range problems…

I've read a lot here on the forum and throughout the internet, made the dipole antenna modification on the radio module attached to the gateway, changed the radio channel (found out that around 2401 MHz i had an unused spectrum) but my range is about 6-8 meters. Im even having difficulty receiving the signal from a node on the upper flor, placed almost on top of the gateway. I live in Europe where there is a more "dense" type of construction so i guess thats a problem too and i'm even trying to hide the gateway inside a cabinet…

I know the NRF24 module is allegedly sensible to the power supply so im including the capacitor between Vcc and ground but im using the 3.3v pin from the Arduino Nano (5v version) to power the radio… And trying to re-use old Nokia phone chargers (yeah, not regulated but they seem to work).

I would like your experienced advice guys, regarding the nodes and gateway placement (antenna placed outside cabinets and orientation), should i build repeater nodes, recommended 5v power supplies (and 3.3v regulators) that you think should be used, should the radio be connected to its own power supply (or through a regulator) and not the 3.3v Nano pin and what kind of range you get indoors because for a 60 m range radio module, 1/10th of this with just 1 wall in between is just disappointing…

Thanks a lot for your attention!

sundberg84

@titvs Welcome to the communicy! Great looking case you made!
Some tips.

Make sure you solder the capacitor as close as possible to the radio.
Try 4,7 and 47uF or some other values. Sometimes the radio needs higher caps
Try to power the radio from a better source than the voltage regulator on the nano.
Try another radio (we have a debug flowchart you can follow - this can be both gw and/or node issue!)
Try to move the node closer and see what happens - might be in need of a repeater.

If you only have one gw and one sensor it might be hard to know which one you need to improve so try not to use all your time on one side. As you probably seen there are alot of fake radios as well... this might be an issue.

In my setup (two floors) I need to have two repeaters on the ground floor and then my GW is in a concrete celler using a high power nrf radio.

scalz

Hi,

Lot of parameters can affect range.
You don't show your node assembly, but in general here some infos:

the first point to pay attention, as sundberg said, better choose good quality module when possible.
Important to remember: the max range given by module manufacturer is always free of sight. Sometimes they provide indoor range but it depends on the final usecase and environment. It's like cars, mileage is tested in best conditions :)
of course a stable power supply with less ripples/noise as possible
bitrate settings of radio module
orientation of antenna is better vertical.
antenna type
antenna height position of your gw and node
no electronics, metal under antenna
unwanted rf signals in the environment
home construction materials and their rf attenuation. Not a big problem for drywall, but a concrete wall will impact a lot range, and will for example attenuate the range twice at 2.4ghz than subghz
node construction material can have an impact and detunes antenna (depending on antenna type)
Another very important parameter is the GND size of your device has a huge impact on performance (including pcb shape and routes).
The smaller gnd available the smaller range (no magic): it can reduce gain of antenna, narrow the band and shift freq too. In that case, even with high RF TX power, you could get poor RSSI and range. Therefore it would waste energy for battery powered nodes.
Regarding this point, rf module manufacturer provides design guidelines, and show their perf regarding an ideal size and pcb shape. In general their gnd is huge. This gnd parameters, only on itself, can half your range too.
It's less a problem for 2.4ghz which needs a lot less gnd than subghz. a >35x35 gnd size for a 2.4ghz is ok (I mean the gnd only, not the pcb size with all parts and routes. The lower the freq the bigger gnd needed, so subghz needs way more gnd.
On other side nrf24 has 0dB max in TX mode vs 13dB for rfm69 non-PA, and 4-6dB delta can double the range..

As you can see, it's about compromise with a lot of parameters (and these are only the firsts which come to my head).

If not already done, I would suggest you to use nrf24 PA/LNA for your gw. Or pick a better rf module for your application if you want to limit number of repeater.

kimot

Use RFM69.

My ESP8266 gateway with RFM69 with 1/4 wavelength wire antenne at centre of my concrete house and arduino with the same module in distance of cca 60 m out of house - signal OK without repeaters.
868 MHz

titvs

Hi everyone.

Thanks for all the info! I appreciate it, really.

Well, today i did additional testing and its a range problem since 2 nodes have the same behaviour on the same location. If i move them closer to the gateway, they get connected.
Since i already have a bunch of NRF24 modules (and integrated them on my little boxes), ill try to make this work with them. If i knew that using RFM69 would be better across physical barriers, i would go for them… In reality we are trying to build the network inside a house... :) Anyway, thanks for the tip @kimot . Will change to them if i dont get the NRF24 network to work properly.
So, i already orderer a NRF24/PA/LNA for my gateway and an independent switching power supply. Hope that boosts the gateway.

Today i programmed a Nano to be a repeater but it seems i cant find a guide to set this properly since the node further away doesnt get connected. The gateway sees the repeater though… Do i need to change anything on the original example repeater code? As setting up NODE_ID and CHILD_ID? Ive read somewhere here in the forum thats just uploading the example code to an arduino and thats it… Will try to get the debug output of the repeater (need to connect it to a laptop).

Other thing, what type of 5v power supplies do you guys recommend? And 3.3v step down modules?

I will also upload my boxes stl to Thingiverse if your interested. Ive made a more compact model...

Thanks again.

Carywin

Good luck! I tried sticking with NRF long past when would be sensible, and still ended up changing to RFM69 (433 MHz in my case).
Inner-city areas are just too crowded on 2.4G now, but paradoxically 433 MHz is becoming freeer thanks to the slow death of landlines and DECT phones.

zboblamont

@titvs Attenuation of 2.4GHz signals is your primary problem as @scalz pointed out, and here is a real example:
My Gateway is in the centre of the masonry/concrete house, with 433Mz communications to Nodes currently at 10-15m radius, but previously tested out to 30m without any problems.
The Router maintaining the Domoticz link to my Wifi laptop is at the front of the house nearest the Gas Meter Node, if I go to reprogram the Gas Node I lose the Wifi signal even at 10m, but the Node continues comms flawlessly.
Boosting the signal with a reflector behind the Node or changing to higher power output might increase the attenuated signal sufficiently to make the connection, but failing that, change to lower frequency devices.

Yveaux

@titvs said in Introductions and Range Issues:

i already orderer a NRF24/PA/LNA

Please make sure to buy decent quality modules, like the ones from Ebyte. They are only marginally more expensive but will save you a lot of trouble.

I'm only using nrf24 at home and covered my whole house. To counter range issues I've setup a few gateways (one on the ground floor and one in the attic for example)

sundberg84

@titvs - a gateway could be run through a good quality (genuine) phoneadapter without issues. To point out a regulator in the MySensors shop use the AMS1117 and not LE33ACZ because the later is to weak. You can also use pretty much any other linear regulator that can handle about 1A or more. Dont forget to check the datasheet for recommended setup with capacitors.

The only thing you need to do is to setup for a repeater is (example here)

// Enable repeater functionality for this node
define MY_REPEATER_FEATURE

I would also really check the capacitors again and try some different values.

rozpruwacz

@titvs I also would recommend to go for rfm69. I had exactly same problems as you, and tried a lot of differenr nrf24 modules and still couldnt get a descent result. As soon as i switched to rfm69 all my problems disappeared :) after all i spent more money on nrf24 modules than i would spend on rfm69 if i would start with them. Use nrf24 to rfm69 adapter board for easy transition.

joaoabs

@rozpruwacz said in Introductions and Range Issues:

@titvs I also would recommend to go for rfm69. I had exactly same problems as you, and tried a lot of differenr nrf24 modules and still couldnt get a descent result. As soon as i switched to rfm69 all my problems disappeared :) after all i spent more money on nrf24 modules than i would spend on rfm69 if i would start with them. Use nrf24 to rfm69 adapter board for easy transition.

Hi,

I'm also experiencing some troubles with NRF24+'s, but I already have a considerable number of nodes with it. Most of them have the 2x4 pin header like the ac/dc ssd relay and the slim node.

Is there any adapter that could easily adapt ( ! ) from the NRF24+ format to the RFM69?

Thanks,
Joaoabs

rozpruwacz

https://www.mysensors.org/hardware/nrf2rfm69
I tested it and it works. It is just a little bit larger than a typical nrf24 module.

titvs

Thanks for all the input guys and the vote of confidence regarding the NRF24! :D

So, since there are a lot of people telling to go for the RFM69, I've ordered a couple of them to do some testing. Im still going to test the NRF24/PA/LNA but after all you guys said, im not feeling very confident…

If everything doesnt go according to pIan, i guess im going to have to try to fit the RFM69 inside my already printed boxes and have an antena protruding out of the box… not very pretty… Ah well. Nothing is perfect. :)

Anyway, I think there should be somekind of note on the radio page of the main website, stating this kind of problem regarding range and construction type.

Will keep in touch.

rozpruwacz

@titvs said in Introductions and Range Issues:

If everything doesnt go according to pIan, i guess im going to have to try to fit the RFM69 inside my already printed boxes and have an antena protruding out of the box… not very pretty…

You don't have to :) just use a flexible, insulated 1/4 wavelenght wire antenna and keep it inside the box. It does not have to be straight.

Yveaux

@joaoabs said in Introductions and Range Issues:

Is there any adapter that could easily adapt ( ! ) from the NRF24+ format to the RFM69?

As @rozpruwacz said it works, but keep in mind that the RFM69 is not 5V tolerant on its IO lines like the nRF24.
This means that if you plan to use it connected to a 5V arduino you have to put a level shifter in between.
Also, make sure to connect the IRQ line, which is optional for nRF24 but required for RFM69.

sundberg84

@titvs said in Introductions and Range Issues:

Anyway, I think there should be somekind of note on the radio page of the main website, stating this kind of problem regarding range and construction type.

I have around 25 nodes using Nrf24 radio. Once you have found your way and how to test them before deployment they work very good. Sure, its easier with the RFM69 but expensive and as @Yveaux said not 5v tolerant.

For me I have a fixed node on my lab-bench with a socket for the radio. This way I can test any new radio before I use them. Most of them work great with a 4,7uF cap. In your setup I would guess it will work much better once you get the gateway a proper and stable radio.

alowhum

isn't the NRF24 able to use a higher frequency than wifi? I read that if you choose channel 100 you get much better results in Europe.

mfalkvidd

@alowhum it might work better, but you'll need to consider if it is worth breaking the law.

In EU, the highest nrf24 channel that can be used legally is channel 83.

rozpruwacz

@mfalkvidd I also tried that outlaw trick and the results weren't satisfying :) I think that your microwave is more affecting the comunication than the wifi. This is another issue that I think that 2.4GHz is not suited for HA - can't turn on lights when using microwave is not acceptable :D

titvs

@sundberg84 said in Introductions and Range Issues:

I have around 25 nodes using Nrf24 radio. Once you have found your way and how to test them before deployment they work very good. Sure, its easier with the RFM69 but expensive and as @Yveaux said not 5v tolerant.

Yeah, they are really more expensive than the NRF24. But still cheaper than the cost of a repeater node (NRF24 + Nano) even without considering the power supply... Well, i guess that each case is different. :)

As for the 5v logic vs 3.3 thats also a problem with 5v Nanos. I think they need something like "this" ?

I'll still do tests with the NRF24/PA/LNA and with repeater nodes but i think i wont be so lucky with a weather station node (needs to be outside) that im planning to add to the system. Lets wait and see. :)

I'll also prepare the STL files to upload to Thingiverse of my box. Need to take some pictures of the assembly first. :)

Thanks for the input!

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