Anyone with experience of DS-RFLoRa-2 (RF Solutions)?

rmeldo

Senior Member
Hello,

I would like to experiment with the possibilities offered by the LoRa technology for range, reliability, power consumption, etc.

I am considering the module form RF solutions http://www.rfsolutions.co.uk/acatalog/FM-LORA-Transceiver-Module-pre-set-to-868MHz.html#SID=335


The reasons I find this little one attractive are:

integrated
  • antenna
  • Acceptable price
  • small size
  • low power consumption (claimed)

The application would be to send temperature from inside flats to a receiver placed outside 50 metres away.

Has anyone worked with these devices? Was it successful? The datasheet gives an example implementation using a PIC16F886 but could I use a Picaxe? What are the "gotcha" to watch out for?

Many thanks
Riccardo
 

manuka

Senior Member
Splutter -just 50 metres? Are those flats "inside" or D-E-E-P inside ? Your investigation interest is applauded, but - c'mon mate -you could whistle that far!

For occasional (?) temperature monitoring even a simple PICAXE-08M/ DS18B20/ 443 MHz ASK system may do.The exceptional range of LoRa™ suits links to kilometres in built up areas, or astounding 10s-100s km if elevated & loS (line of sight).

As for gotchas. Single chipper SPI interfaced LoRa™ systems featuring just the Semtech (or HopeRF) "7 a side" SX127x module are quite demanding to work with. You may well be better to initially consider a TTL serial friendly 2 chipper - even these need significant setup tweaking,which thankfully a humble 08M can handle OK .

See => http://www.instructables.com/id/Introducing-LoRa-/ for a LoRa™ overview. Stan.
 

rmeldo

Senior Member
Thanks,

I have just read your instructable. Very useful as usual.

I know that 50 metres is, to paraphrase you, within sound processing distance. However our building seems to behave like a black hole as far as radio signals are concerned. My WiFi signal barely manages to go through a single wall.

In your instructable you wrote: "LoRa's ability to punch thru' obstructing buildings in crowded Asian cities has no doubt been been appealing". That is what I am after. Also I am curious to try LoRa.

I'll tried to look for the chinese 2-chips boards but they seem not be easy to source.

RF Solutions do this one which looks like it can work with UART:

http://www.rfsolutions.co.uk/acatalog/RF-Telemetry-module-SIL-package-GAMMA-868R.html#SID=281

I'll keep looking.

Thanks
Riccardo


thanks
Riccardo
 

manuka

Senior Member
Riccardo: That RF Solutions offering looks impressive, but it's perhaps an overkill for LoRa™ newbies. My initial 2014 LoRa™ investigations used Dorji's DRF1278 modules,which have since seen decent RPi project use . Issues are reported however=> https://www.youtube.com/watch?v=cuDpOiFhCnI

Dorji's offerings can be EBay sourced ,but such cheaper lookalikes as Chengdu EBYTEs E32-TTL-100 or bare bones (& free shipping) E32-TTL-100S1 may tempt?

Update in response to your post above : MicroChip's LoRa™ RN2483 offering is probably THE best bet all up !

Thought: Forum regular & "$50SAT" guru SRNET lives over in Cardiff, & is very experienced with HopeRF's single chip LoRa™ offering. He may be up to sharing resources ? Stan.
 
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rmeldo

Senior Member
Happy to collaborate.

Starting form scratch I have a lot of initial learning to do but eventually my intention is to try and build a sort of gateway capable of managing a small number of sensors (5 to 100). It seems to me that a Raspberry Pi should have the muscle to handle this.


I Still need to google other people's approach and solutions of this problem.

For the moment I have thought of a possible way to go but feel free to put me right as I must admit I don't have much of a clue about how these things work. Here it goes:

The challenge is to avoid the sensors talking over each other, so I was thinking that I could use the gateway to schedule the transmissions from the sensor by communicating the time for the next upload to the sensor.

So if, say the desired upload frequency is 15 minutes (900 seconds) then the start of the various sensor transmissions should be spaced by 9 seconds. Hopefully, for the sake of battery usage the transmission of a temperature + voltage + sensor ID will not take that long.

The thinking is that at power up the sensor would send the temperature to the gateway and wait for acknowledgement and the time to the next upload. Then it would shut down and wake up at the instructed time to transmit the temperature again. It doesn't wait for acknowledgement but it goes to sleep for 15 minutes when it wakes up to transmit again, etc.


The gateway would always listen for temperature uploads, checks for new sensors and provide them with the time to the next message.

How does it sound?

Thanks
Riccardo
 

srnet

Senior Member
There is much about LoRa to be found here;

https://goo.gl/IeEiC1

Code for PICAXE, Micromite and Arduino.

Remember that LoRa is just the transport mechanism, what you want to do could be achieved with most types of radio device.

The advantage of LoRa in you circumstance is that given its so long range, you would probably use a very high data rate, meaning packets would be very short time wise.

If the packets are short then a simple send and acknowledge system with a random delay between retries, might be perfectly adequate, no need to over complicate things.
 

srnet

Senior Member
And with regards the Pi, whilst it may be suitable for the central collector, its way too power hungry for the sensor end.

Its the remote wireless sensors where very low power micro controllers such as PICAXE are ideal. They can be self contained and run off a pair of AAs for 5 years or so.
 

rmeldo

Senior Member
Thanks srnet,

I will check the link out.

With regards to the remote node it is clear that Picaxe or a pic are ideal. Even Arduino might be too power hungry CORRECTION: inSrnet material there is mention of the Arduino pro mini, without the USB chip on board. That one might be good for power consumption as well.

Riccardo
 
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Camerart

Member
Hi,
I am a beginner with the SX12xx range, and have a SX1276 set-up with an 18F2431 PIC.

I am trying to set-up the RegOpMpde 0x01 register, but there seems to be a problem! I am not able to set the required BITs. I did a test where I sent every choice from 0-255, and read the result on an LCD. I could only load 0-4-8-12-16-80-64-192-128-132-136-140-144-148-152-156-208. So for example, none of these choices have BIT 5 in them. If I try a similar test on the RegBitrateLsb 0x03 register, I am able to set any combination of bits.

Is it something blocking the WRITE or could it be a Chip fault.

Any ides, please?

Camerart.
 

srnet

Senior Member
I am a beginner with the SX12xx range, and have a SX1276 set-up with an 18F2431 PIC.
You asked a similar question over in the RCGroups forums, to which I took the time to respond, but there was no reply.

You said you were using and RFM69 with a SX1276 on it, but the RFM69 module uses the SX1231, they are completly different ICs.
 

hippy

Technical Support
Staff member
First thing to do might be to read the registers of the SXwhatever immediately after power-up and see what default power-on-reset values have been set. Then you can compare what you have with the various datasheets to see what matches and determine exactly what the device is.

Added: An SX1321 as srnet suggests it may be would seem to match the behaviour you are seeing; bit 5 of register 0x01 is write only "always reads as zero".
 
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Camerart

Member
You asked a similar question over in the RCGroups forums, to which I took the time to respond, but there was no reply.

You said you were using and RFM69 with a SX1276 on it, but the RFM69 module uses the SX1231, they are completly different ICs.
Hi S,
I've responded to the Rcgroups answer, sorry for being slow, I didn't receive notification.

I asked the suppliers of my first cheap Chip/modules (Auction site) and the said they are SX1276, but I'll double check and get the SX1231 data sheet.

chip/modues = boards with SX12xx and crystal, but no controller chip. I use 18F2431 PIC for control.

I'm still trying to figure out how to switch OOK. Is it by switching RegOpMode or RegPaConfig or something else.

Cheers, C.
 
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srnet

Senior Member
If it is a SX1276 (LoRa) device then there is a reason you get odd results writing and reading register $01 as is clearly explained in the device data sheet.

As for the rest, the datasheet says of bit 7 for RegOpMode;

0 FSK/OOK Mode
1 LoRaTM Mode

With the device flipped into the FSK\OOK mode register set you can then proceed to setup RegOpMode for FSK or OOK.

If your configuring the device and writing the code from scratch you will need to read the datasheet (all of it) or you will get complety lost.
 
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Camerart

Member
First thing to do might be to read the registers of the SXwhatever immediately after power-up and see what default power-on-reset values have been set. Then you can compare what you have with the various datasheets to see what matches and determine exactly what the device is.

Added: An SX1321 as srnet suggests it may be would seem to match the behaviour you are seeing; bit 5 of register 0x01 is write only "always reads as zero".
Hi H,
Good suggestion, Ill try that tomorrow, thanks.
C.
 

srnet

Senior Member
Hi H,
Good suggestion, Ill try that tomorrow, thanks.
C.
But then the regopmode of the SX1276 device, can behave in the same way, bits 4,5 are marked as read only and reserved, so could exhibit the same behaviour.
 
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Camerart

Member
If it is a SX1276 (LoRa) device then there is a reason you get odd results writing and reading register $01 as is clearly explained in the device data sheet.

As for the rest, the datasheet says of bit 7 for RegOpMode;

0 FSK/OOK Mode
1 LoRaTM Mode

With the device flipped into the FSK\OOK mode register set you can then proceed to setup RegOpMode for FSK or OOK.

If your configuring the device and writing the code from scratch you will need to read the datasheet (all of it) or you will get complety lost.
Hi S,

I must have read the Line explaining the 'wnr bit' needing to be 1, five or six times, and it still had to be pointed out to me. I don't find reading data sheets easy, and I appreciate your patience. I find these modules fascinating, this is why I will keep trying.

I'll follow your suggestions along with Hippys tomorrow.

Todays question: Is OOK switched ON/OFF in RegOpMode, or the power amplifier by changing the output, or is the power amplifier switched by PINS. I will then concentrate on those relevant pages.

Cheers, C.
 

srnet

Senior Member
I think you may be missing that the devices are packet based, you fill the fifo with data, turn on TX and the packet goes out.

FSK (and maybe OOK) can be controlled direct by a pin, DIO2, in continuous mode which is useful for sending Audio tones. Its mentioned in the manual, which is why I suggested you read all of it, if you read only the bits of the manual you think are relavent, you will miss stuff.

I have not played with OOK, cant imagine why anyone would bother to use a LoRa device for OOK.
 

Camerart

Member
I think you may be missing that the devices are packet based, you fill the fifo with data, turn on TX and the packet goes out.

FSK (and maybe OOK) can be controlled direct by a pin, DIO2, in continuous mode which is useful for sending Audio tones. Its mentioned in the manual, which is why I suggested you read all of it, if you read only the bits of the manual you think are relavent, you will miss stuff.

I have not played with OOK, cant imagine why anyone would bother to use a LoRa device for OOK.
Hi S,
I have read the whole manual 5 or six times, but I have mild dyslexia, so it doesn't 'stick' like your brain holds the information. It does slowly go in, but I need to pick off today's relevant information, and program it, then the computer remembers it for me. A month later and it is cloudy again, but I still have the program. I'm used to it:) When I first started this project, I asked everyone I could to help me translate one of your excellent programs, all too busy. The only way I can do it is this way: Learn OOK then PSK then hopefully the very complicated LoRa system.

My first project is to make a pair of Morse transceivers.

I understand from what you say, that perhaps OOK is controlled by PIN Dio2,no packets involved.

I feel I've hyjacked this thread, so I've started my own: http://www.picaxeforum.co.uk/newthread.php?do=newthread&f=2
P.S. You are both correct, it is the SX1231 CHIP, thanks.

Thanks, C.
 
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srnet

Senior Member
Programming a new RF module from scratch is really for very experienced constructors well versed in the electronics and able to read and absorb the details in a datasheet.

If your strating from scratch and your link does not work you will find it extremly difficult to work out whether its TX or RX that is the problem.

Mere mortals (and I include myself here) will need to utilise the help of some available working code, of whatever paltform.

For LoRa I started with some published AVR\C code about which I knew nothing at the time and got that published TX and RX code working on an Arduino. Next I found the point where the AVR\C program wrote out to the LoRa device and changed it to print to terminal each and every device write and read. I replicated all those writes exactly on a PICAXE and worked out what the few reads were for. Eventually I had the PICAXE transmitting, the AVR platform receiving. It was then a case of getting the PICAXE working as RX.

With a PICAXE TX and RX working, I could take a view on what the code was actually doing and which bits were doing what.

If I had tried to get the PICAXE LoRa code working from scratch, without the benefit of a working TX and RX on another platform, I would likely still be working on it 2 years later.
 

Camerart

Member
Programming a new RF module from scratch is really for very experienced constructors well versed in the electronics and able to read and absorb the details in a datasheet.

If your strating from scratch and your link does not work you will find it extremly difficult to work out whether its TX or RX that is the problem.

Mere mortals (and I include myself here) will need to utilise the help of some available working code, of whatever paltform.

For LoRa I started with some published AVR\C code about which I knew nothing at the time and got that published TX and RX code working on an Arduino. Next I found the point where the AVR\C program wrote out to the LoRa device and changed it to print to terminal each and every device write and read. I replicated all those writes exactly on a PICAXE and worked out what the few reads were for. Eventually I had the PICAXE transmitting, the AVR platform receiving. It was then a case of getting the PICAXE working as RX.

With a PICAXE TX and RX working, I could take a view on what the code was actually doing and which bits were doing what.

If I had tried to get the PICAXE LoRa code working from scratch, without the benefit of a working TX and RX on another platform, I would likely still be working on it 2 years later.
Hi S,
So far I've spent weeks trying to get some sense out of the SX, and searched for examples to follow. Your Micromite Mk2 is written in Basic, and it has helped me quite a bit.

Since I changed DATA sheets to the SX1231, as suggested, I now have my chip, switching on and off as seen on an SDRadio.

Another baby step tomorrow, in the warm with the radio on. I've dreamt of days like these:cool:

(You may know, that I tried to open my own thread, but it isn't in the Picaxe rules)

Thanks for your help so far, I hope you can contribute to my Electrotechonline thread. (Goodness knows I need it)
Cheers, C.
 

johndk

Senior Member
I've been playing with a Dorji LoRa module for a while. Very impressive. It has 7 power settings. At lowest power, I get a range of at least 400m in an open setting. I didn't test beyond that because I don't need more than that for now.
This is the link.
http://www.ebay.com/itm/Semtech-LoRa-SX1276-SX1278-UART-Interface-RF-wireless-module-DRF1278DM-/191273642230?hash=item2c88cc28f6:g:51gAAOSwPe1T3kHd
I've been dealing with the Dorji Group on ebay for a while. Very reputable and helpful.
http://www.ebay.com/usr/dorjigroup

It is a little different from straightforward radio coms as there are more parameters to deal with. But the range is amazing. I'm gearing up to try for a 2km over water.
 

Camerart

Member
Programming a new RF module from scratch is really for very experienced constructors well versed in the electronics and able to read and absorb the details in a datasheet.

If your strating from scratch and your link does not work you will find it extremly difficult to work out whether its TX or RX that is the problem.

Mere mortals (and I include myself here) will need to utilise the help of some available working code, of whatever paltform.

For LoRa I started with some published AVR\C code about which I knew nothing at the time and got that published TX and RX code working on an Arduino. Next I found the point where the AVR\C program wrote out to the LoRa device and changed it to print to terminal each and every device write and read. I replicated all those writes exactly on a PICAXE and worked out what the few reads were for. Eventually I had the PICAXE transmitting, the AVR platform receiving. It was then a case of getting the PICAXE working as RX.

With a PICAXE TX and RX working, I could take a view on what the code was actually doing and which bits were doing what.

If I had tried to get the PICAXE LoRa code working from scratch, without the benefit of a working TX and RX on another platform, I would likely still be working on it 2 years later.
Hi S,
What did you mean "your link does not work" in your answer, please?

EDIT: (you will find it extremly difficult to work out whether its TX or RX that is the problem.) What I'm finding so far is, if I set the SX1231 to TX there is no signal, and visa versa with Rx. Is this what you meant?
C.
 
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Camerart

Member
Hi J,
I've been failing to get some SX1231 CHIP MODULE working, and today had a good look how the CHIP PINS are connected to the board PINS, and couldn't see how the RXTX PIN (19 in this case) is connected. It appears to be unconnected. So I've almost given up with these SX1231 CHIPs.

I searched for SX1276-8 CHIPS, and tried Semtech, but the minimum order is 3000. After much searching, I found your link,and ordered some from Dorji. (SX1278)

Thanks for the link, Camerart.



I've been playing with a Dorji LoRa module for a while. Very impressive. It has 7 power settings. At lowest power, I get a range of at least 400m in an open setting. I didn't test beyond that because I don't need more than that for now.
This is the link.
http://www.ebay.com/itm/Semtech-LoRa-SX1276-SX1278-UART-Interface-RF-wireless-module-DRF1278DM-/191273642230?hash=item2c88cc28f6:g:51gAAOSwPe1T3kHd
I've been dealing with the Dorji Group on ebay for a while. Very reputable and helpful.
http://www.ebay.com/usr/dorjigroup

It is a little different from straightforward radio coms as there are more parameters to deal with. But the range is amazing. I'm gearing up to try for a 2km over water.
 
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