Learn to use other available troubleshooting tools
besides the IDE indicators & reported error messages mentioned above.
The tiny LEDs
on an Arduino compatible or Arduino Ethernet Shield can tell you some things
. When powered, a healthy Arduino's PWR LED glows a solid green. When connecting a DHT11 sensor to an Arduino, I once traded power & ground so that the Arduino would not program or anything. The PWR LED was also off. When getting an upload, an Arduino's RX (receive) & TX (transmit) LEDs should consistently flash until finished. If there's uploading trouble, RX / TX will flash & stop 4 times before publishing an error on the IDE. When the RFM69 Gateway & a RFM69 end node are communicating occasionally, the end node's SCK LED will flash yellow very briefly.
When the RFM69 Gateway is connected to power only, the red LED glows a solid red on its Ethernet Shield (ES). ES's green TX LED will flash in bursts. When the RFM69 Gateway is connected to power AND a router via an Ethernet Cable & is successfully connected to the home network & to the MQTT service on a computer, its ES's PWR LED is solid red, TX & RX LEDs flash green, & LEDs extending from the PWR LED show a variety of solid & flashing yellow.
For this RFM69 Home Automation project, CompuTourist related sketches have debugging modes that show positive & error messages on the serial monitor
. At least until you get a Gateway or end node working have the debug mode on & the device connected to the IDE computer's USB. Then open the IDE's serial monitor (see above) & set it to the same baud as in the sketch (115200 in the Gateway & end node sketches). Study the messages on the serial monitor. Find a message's source in the sketch to see more what it's telling you.
For example, if you are working with a CompuTourist derived Gateway, you should get some result on the serial monitor, even just initial start up & error messages like "Gateway Software Version..." "Failed to configure Ethernet using DHCP" "connecting..." "connection failed..." Those are clues for what is successful & not.
In the Gateway sketch we see the following code which hints how we can add troubleshooting clues to our sketch which will display on the serial monitor:
Serial.print("Gateway Software Version ");
On the serial monitor, the first line LITERALLY displays what's insider the left-right parentheses ("Gateway Software..."). The second line continues where the first line left off, displaying the contents ("GW V2.2") of the variable named VERSION, & then kicking serial monitor display to a new line on the screen.
Sometimes we try to troubleshoot with too much hardware installed. In his Newbie... thread
, lhw455's Gateway in debug mode was showing nothing on the IDE's serial monitor. At my suggestion, lhw455 progressively removed plugged-in parts & watched the serial monitor until he finally got results. At that point all was removed from the Arduino compatible, including the Ethernet Shield, indicating the Shield is defective. That goes along with an earlier clue that lhw455 was not able to upload to the Gateway unit until he removed the Ethernet Shield from the Arduino compatible. Thus, by progressively adding or subtracting from our hardware components, we can refine our troubleshooting with debugging modes & serial monitor. In this thread
, I document starting as simple as possible & building step by step
& getting success before moving on.
If you have OpenHAB logs displaying in a Windows cmd console or a Linux Terminal window, they also display messages, positive & errors. One can learn & troubleshoot from those. This post
will give links to hints for troubleshooting OpenHAB errors