RFLink up and running, scanning 433.92 MHz

Today I soldered up the RFLink (tricky!) and it actually works...

When I plugged it into my Mac, everything lit up - hurrah. Now to flash the RFLink code into the Arduino... For this I had to use the avrdude program, rather than the Arduino IDE - I only have the Arduino hex file, not the source. I wrote a script to save typing it all in wrongly multiple times :-)... Bits in bold are specific to my installation.

loadArduino.sh:

# Script to load a file into Arduino
/Applications/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude -v -p atmega2560 -c stk500 -P /dev/cu.usbmodem411 -b 115200 -D -U flash:w:/Users/john/Downloads/RFLink_v1/RFLink.cpp.hex:i -C /Applications/Arduino.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf

And here's the output from running it, pretty interesting stuff actually! I assume the same thing happens with the Arduino IDE, except the output is swallowed up and thrown away.

Macintosh-Gouk:~ john$ ./loadArduino.sh 

avrdude: Version 6.3, compiled on Dec 16 2016 at 13:32:25
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "/Applications/Arduino.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf"
         User configuration file is "/Users/john/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/cu.usbmodem411
         Using Programmer              : stk500
         Overriding Baud Rate          : 115200
         AVR Part                      : ATmega2560
         Chip Erase delay              : 9000 us
         PAGEL                         : PD7
         BS2                           : PA0
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 200
         StabDelay                     : 100
         CmdexeDelay                   : 25
         SyncLoops                     : 32
         ByteDelay                     : 0
         PollIndex                     : 3
         PollValue                     : 0x53
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom        65    10     8    0 no       4096    8      0  9000  9000 0x00 0x00
           flash         65    10   256    0 yes    262144  256   1024  4500  4500 0x00 0x00
           lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           efuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           calibration    0     0     0    0 no          1    0      0     0     0 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00

         Programmer Type : STK500V2
         Description     : Atmel STK500
         Programmer Model: AVRISP
         Hardware Version: 15
         Firmware Version Master : 2.10
         Vtarget         : 0.0 V
         SCK period      : 0.1 us

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e9801 (probably m2560)
avrdude: safemode: hfuse reads as D8
avrdude: safemode: efuse reads as FD
avrdude: reading input file "/Users/john/Downloads/RFLink_v1/RFLink.cpp.hex"
avrdude: writing flash (199364 bytes):

Writing | ################################################## | 100% 31.98s

avrdude: 199364 bytes of flash written
avrdude: verifying flash memory against /Users/john/Downloads/RFLink_v1/RFLink.cpp.hex:
avrdude: load data flash data from input file /Users/john/Downloads/RFLink_v1/RFLink.cpp.hex:
avrdude: input file /Users/john/Downloads/RFLink_v1/RFLink.cpp.hex contains 199364 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 25.55s

avrdude: verifying ...
avrdude: 199364 bytes of flash verified

avrdude: safemode: hfuse reads as D8
avrdude: safemode: efuse reads as FD
avrdude: safemode: Fuses OK (E:FD, H:D8, L:FF)

avrdude done.  Thank you.

Interesting to see that the program reads back and verifies the contents of flash memory. This is a Good Plan!

Sample samplings!!

20;00;Nodo RadioFrequencyLink - RFLink Gateway V1.1 - R48;
20;01;Drayton;ID=ba00;SWITCH=0f;CMD=ON;
20;02;Drayton;ID=ba00;SWITCH=0f;CMD=ON;
20;03;Drayton;ID=f560;SWITCH=1e;CMD=ON;
20;04;Drayton;ID=f560;SWITCH=1e;CMD=ON;
20;05;Drayton;ID=f560;SWITCH=1e;CMD=ON;
20;06;Friedland;ID=59a89aa6;SWITCH=1;CMD=ON;CHIME=01;
20;07;Drayton;ID=ba00;SWITCH=0f;CMD=OFF;
20;08;Drayton;ID=ba00;SWITCH=0f;CMD=OFF;
20;09;Drayton;ID=ba00;SWITCH=0f;CMD=OFF;
20;01;Eurodomest;ID=425082;SWITCH=01;CMD=OFF;

The above messages were received on the usbmodem411 device. Note
  • Someone around here has a Drayton thermostat (!)
  • The front door bell shows up nicely!
  • There's another device around too, not sure what it is

Here's the structure of the messages RFLink produces - <Name> is protocol-specific, and coded inside the Arduino.


Structure:

<Nodeno>;<Name>;<Label>=<value>,…

Just for the hell of it, I tried sending a doorbell command, which didn't work - then I noticed the manual says only receive is supported!

Doorbell command:

10;Friedland;59a89aa6;1;ON;01;

doesn’t work :-( - manual says only receive is supported!

However, you can get RFLink to echo whatever received command you like, to test downstream code, using the "11" command e.g. 

Echo command:

11;20;06;Friedland;ID=59a89aa6;SWITCH=1;CMD=ON;CHIME=01;

And you can ask to see the radio packet information, which is pretty useful if you're trying to work out a protocol I guess, I haven't seen any that it doesn't know. I wonder if it would send anything if it received a signal from a device it didn't already know?

RFDebug output:

20;22;RFDEBUG=ON;
20;23;DEBUG;Pulses=38;Pulses(uSec)=480,930,900,900,900,930,900,420,420,900,420,420,420,420,420,420,900,900,390,420,420,420,420,420,420,420,930,390,420,390,420,420,420,420,420,930,420,6990;
20;24;DEBUG;Pulses=58;Pulses(uSec)=390,390,420,420,420,420,420,420,420,420,420,420,930,1410,900,420,420,420,420,420,420,900,900,900,930,900,900,420,420,930,420,390,420,420,420,420,900,900,420,390,450,360,420,420,420,390,930,420,420,420,420,420,420,420,420,900,420,6990;
20;25;Drayton;ID=560;SWITCH=1e;CMD=ON;
20;26;DEBUG;Pulses=58;Pulses(uSec)=360,390,420,390,420,390,450,390,420,390,420,420,900,1410,900,390,420,390,420,420,420,900,930,900,900,900,900,420,420,900,420,420,420,420,420,420,930,900,420,420,420,390,420,390,420,390,930,420,420,420,390,420,420,420,420,900,420,6990;
20;27;Drayton;ID=f560;SWITCH=1e;CMD=ON;


Comments

  1. Md Younus Meya14 March 2026 at 06:29

    This is an interesting project about getting RFLink up and running with 433.92 MHz devices — it’s always inspiring to see people explore wireless technology and DIY electronics! Learning how to capture and interpret radio signals can open up a lot of fun and useful applications, from weather sensors to home automation. Projects like this help beginners understand how hardware, firmware, and protocols all work together. While this topic is quite technical, many people also work on preserving memories and physical media in their own creative ways. For anyone interested in converting printed photos into digital format with professional help, this guide on Best Photo Scanning Services is a helpful resource with recommendations for quality scanning solutions.

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