Firmware, FactoryTest_wMenu, Unreliable Mini MP3 Player Test, Firmware Version: v0.4.2.3

[ForrestErickson]

Describe the bug
A clear and concise description of what the bug is.
Short Summary of the expected behavior:
Testing with FactoryTest_wMenu

The Mini MP3 playter tests, 4, 5 and 6 should produce consistent test results on a DUT

Short Summary of the buggy behavior:
Test 4 failed reporting,

DFPlayer not detected. Check wiring & power.
DFPlayer initializing Failed (DFPlayer not detected).

Test 4 again and this time passed with message

DFPlayer Mini online.

Test 5 results are normal

Enter command: 5

[5] SD (DFPlayer card)
Reading SD file count (once)...
DFPlayer reports 9 files.

However test 6 makes no sound on speaker and returns unexpected

[Pending command executed] 6
Playing track #1 for ~3 seconds...
Using cached SD file count = 9
DFPlayer volume set to: 20
Did you hear audio from the speaker?
Press Y to PASS or N to FAIL (Enter optional).
(Menu keys abort this step and run next.)

No response -> FAIL
Speaker test: FAIL

[ForrestErickson]

Swap TD5580A Mini MP3 Player with DFRobot

For further investigation I swapped out the player for a true DFRobot and the tests were normal.
Command 4 Returned
DFPlayer detected and initialized (SD selected).
DFPlayer Mini online.
And Speaker clicked

Command 5 Returned expected results.
DUT returned DFPlayer reports 9 files.

Command 6 Returned Expected behavior
DUT played the OK file.

Compare response time

I put the TD5580A back in and lets measure the response time

Command 4
07:33:49.099 -> Enter command: 4
07:34:04.259 -> Initializing DFPlayer (UART2)...
07:34:06.722 -> DFPlayer not detected. Check wiring & power.
07:34:06.754 -> DFPlayer initializing Failed (DFPlayer not detected).
From Initializing DFPlayer (UART2)... to DFPlayer initializing Failed (DFPlayer not detected).
Difference of 2.495 seconds

I put the true DF Robot back in and lets measure the response time

Command 4
07:35:57.430 -> Enter command: 4
07:36:02.696 -> Initializing DFPlayer (UART2)...
07:36:06.580 -> DFPlayer detected and initialized (SD selected).
07:36:06.580 -> DFPlayer Mini online.
From Initializing DFPlayer (UART2)... to DFPlayer Mini online.
Difference of 3.884 seconds

RESULT: The successful DFRobot player took longer for success than the filing TD5580A.

[ForrestErickson]

Code Review

Is this command dfPlayer.setTimeOut(1000); placed appropriately?

If more time may be needed should this command be before line 492 or even before line 488?

What exactly does dfPlayer.setTimeOut(1000); do?

AI Overview
The line dfPlayer.setTimeOut(1000); sets the maximum time, in milliseconds (ms), that the Arduino will wait for a response from the DFPlayer Mini module when communicating with it over a serial connection.
Here's a breakdown of its purpose:
Communication Mechanism: The Arduino communicates with the DFPlayer Mini by sending commands and receiving feedback via a serial interface (like SoftwareSerial).
Timeout Value: The 1000 argument means the Arduino will wait for up to 1 second (1000 ms) for the DFPlayer to acknowledge a command or send data back.
Error Handling: If the Arduino doesn't receive a valid response within that 1-second window, the command is considered to have timed out, and the library will typically report a timeout error. This allows your sketch to handle potential communication problems (e.g., the module is busy, disconnected, or wiring issues) without freezing indefinitely.
Default Setting: This value often defaults to 1000 ms in the library, so this line explicitly confirms that default or sets it if it was previously changed.
Setting an appropriate timeout is crucial because the DFPlayer Mini can sometimes be slow to respond, especially during initialization or when accessing the SD card, and some users find adjusting this value helps with communication stability.