RFM69HW communication not working

Projects Networking, Protocols, and Devices
1

Hi Arduino Users,

I have communication problem between two Arduino Uno boards using RF69MHW (RFM69HW-433S2 modules.

DataSheet of RFM69HW: https://www.pollin.de/productdownloads/D810800D.PDF

Target Setup:

image
image1145×548 119 KB

Extract from the datasheet:

image
image808×670 59.2 KB

image
image803×610 58.2 KB

  • How to connect the ground pins of RFM69HW?
  • what about the NC Pin? Do I need to connect it also to Ground?

My Source Code is using RadioHead library. I am using the same source code as attached here:

https://learn.adafruit.com/adafruit-feather-32u4-radio-with-rfm69hcw-module/using-the-rfm69-radio

My assumption is that the issue is somewhere in the Target setup.

Output - Serial Prints:

Rx Arduino:
RF Radio Init OK!
RF Radio Set Freq OK!
Received [14]: Hello World #0
RSSI: -27
RF Radio Init OK!
RF Radio Set Freq OK!
Received [14]: Hello World #1
RSSI: -27
(serial print stopped)

Tx Arduino:
SenRF Radio Init OK!
RF Radio Set Freq OK!
Sending Hello World #0
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #1
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #2
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #3
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #4
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #5
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #6
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #7
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #8
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #9
(serial print continues as above #10, #11)

It seems that Rx Arduino is not sending any message back.

I am looking forward to every hint/idea. Thanks in advance

2

What's the weird schematic. This connection is completely wrong and can even fry the module or arduino. Did you use the logic level converter as voltage converter for power lines?
How the module and Arduino communicate with each other - you do not have a single signal line connected. To communicate with the module, the SPI bus is used; the MOSI MISO and SCK pins on the module are intended for this - all of them are not used in the diagram.

3

Additionnally, this tutorial and code

is not for the module from your picture

4

I hope the following scematic is more precise

image
image1178×566 138 KB

5

It looks like...
But the source code from your link is not for your module.

6

never attempted to use RFM69HW modules with a UNO

however, using RFM69HW modules connected to ESP32s when I run the Adafruit programs in your reference I get
RadioHead69_RawDemo_TX output

RFM69 radio init OK!
RFM69 radio @868 MHz
Sending Hello World #0
No reply, is another RFM69 listening?
Sending Hello World #1
No reply, is another RFM69 listening?
Sending Hello World #2
No reply, is another RFM69 listening?
Sending Hello World #3
No reply, is another RFM69 listening?
Sending Hello World #4
No reply, is another RFM69 listening?
Sending Hello World #5
Got a reply: And hello back to you
Sending Hello World #6
Got a reply: And hello back to you
Sending Hello World #7
Got a reply: And hello back to you
Sending Hello World #8
Got a reply: And hello back to you

....
Sending Hello World #433
Got a reply: And hello back to you
Sending Hello World #434
Got a reply: And hello back to you
Sending Hello World #435
Got a reply: And hello back to you
Sending Hello World #436

RadioHead69_RawDemo_RX output

RFM69 radio init OK!
RFM69 radio @868 MHz
Received [14]: Hello World #5
RSSI: -70
Sent a reply
Received [14]: Hello World #6
RSSI: -70
Sent a reply
Received [14]: Hello World #7
RSSI: -71
Sent a reply
Received [14]: Hello World #8
RSSI: -70
Sent a reply
Received [14]: Hello World #9
RSSI: -71
Sent a reply
Received [15]: Hello World #10
RSSI: -70
Sent a reply
Received [15]: Hello World #11
RSSI: -71
Sent a reply
Received [15]: Hello World #12
RSSI: -70
....
Received [16]: Hello World #392
RSSI: -72
Sent a reply
Received [16]: Hello World #393
RSSI: -71
Sent a reply
Received [16]: Hello World #394
RSSI: -72
Sent a reply

you can see the transmitter displays "No reply, is another RFM69 listening?" until I switch on the receiver when it displays "Got a reply: And hello back to you"

7

Hey thank you!!!
it worked now. So made always the mistake that I have switched on the Rx Arduino first.
When I am following your sequence then (switch on tx then rx) it worked:

tx arduino:
RF Radio Init OK!
RF Radio Set Freq OK!
Sending Hello World #0
Packet has been Sent!
No reply, is another RFM69 listening?
SenRF Radio Init OK!
RF Radio Set Freq OK!
Sending Hello World #0
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #1
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #2
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #3
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #4
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #5
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #6
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #7
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #8
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #9
Packet has been Sent!
Got a reply: And hello back to you
Sending Hello World #10
Packet has been Sent!
Got a reply: And hello back to you
Sending Hello World #11
Packet has been Sent!
Got a reply: And hello back to you
Sending Hello World #12
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #13
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #14
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #15
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #16
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #17
Packet has been Sent!
Got a reply: And hello back to you
Sending Hello World #18

rx arduino:
RF Radio Init OK!
RF Radio Set Freq OK!
Received [14]: Hello World #9
RSSI: -27
Sent a reply
Received [15]: Hello World #10
RSSI: -28
Sent a reply
Received [15]: Hello World #11
RSSI: -27
Sent a reply
Received [15]: Hello World #12
RSSI: -28
Sent a reply
Received [15]: Hello World #13
RSSI: -27
Sent a reply
Received [15]: Hello World #14
RSSI: -27
Sent a reply
Received [15]: Hello World #15
RSSI: -28
Sent a reply
Received [15]: Hello World #16
RSSI: -28
Sent a reply
Received [15]: Hello World #17
RSSI: -27
Sent a reply
Received [15]: Hello World #18
RSSI: -28
Sent a reply
Received [15]:

8

what is the reason that the comminication cannot be established reliable?
sometimes I have the following case:

tx arduino:
o reply, is another RFM69 listening?
Sending Hello World #24
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #25
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #26
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #27
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #28
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #29
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #30
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #31
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #32
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #33
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #34
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #35
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #36
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #37
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #38
Packet has been Sent!

rx arduino
(pushing the arduino uno button to reset, but cannot receive anything(and send back))
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!
RF Radio Set Freq OK!
RF Radio Init OK!

and sometimes, the comminication or sending messages suddenly stops:

...
No reply, is another RFM69 listening?
Sending Hello World #69
Packet has been Sent!
No reply, is another RFM69 listening?
Sending Hello World #70
(serial print stopped)

9

the order of starting should not effect the operation - you probably have other problems

10

I assume you are using DuPont jumper wires to connect the devices
they are a source of poor connections and intermittent problems
the RFM69 requires two power + four SPI plus DIO0 - 7 connections in total
you are using level shifters with the UNO so double the connections

one reason why I use 3.3V logic microcontrollers such as the ESP32 is to avoid level shifters hence reducing the number of connections and possible problems

did you solder connections onto the RFM69 device? if so they are not easy to solder onto and you may have a bad soldered joint

could you upload a photo of your system?

11

I've reviewed my connections, and as you previously mentioned, the issue seems to stem from the Dupont jumpers connected to the breadboard. It appears that they aren't establishing reliable connections.

When I touch the cables, I observe that the serial print either pauses or resumes sending messages. Therefore, I plan to solder them onto a PCB board for a more stable connection.

Thank you for your valuable comments. I'll provide an update here once the soldering on the PCB board is complete.

12

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