You could try putting  #include arduino.h right at the start of your source code, also perhaps reinstall the Arduino IDE which should bring a full set of libraries with it.

Before rushing to do a re-write, search the computer for the missing files.   Strictly speaking they are header files rather than libraries, but no need to split hairs!

The problem may simply be that they are in the wrong place and the IDE’s compiler isn’t looking for them in those directories.   (Directory aka folder.)

In C/C++  statements like #include <timer.h>  are common.  The <> brackets mean “look for this file in the compilers list of system directories”.   This is where installed external libraries and processor headers should be.   There are thousands of them.

Alternatively, .h files written locally by a programmer are stored in a list of user defined directories.   They are identified by the quote marked form: #include “timer.h”    For simplicity In the Arduino IDE, local headers like “timer.h” should always be in the same directory as the .ino file.   The editor should open each in a tab.

How to Search

In Linux or mac, I prefer to search from the command line with:  find ~ -name ‘event.h’ -print 2> /dev/null

Or “find ~ -name ‘*.h’ -print 2> /dev/null”    note the * wildcard will list all header files.

In Windows cmd.exe offers the less powerful dir command, so it may be easier to use file explorer.  Start explorer and navigate to your home directory.   Then type ctrl-s  or ctrl-f to open the search box.   Type the filename into the box and with luck Explorer will find it.  Fingers crossed, the missing header files are only misplaced and can be copied to the right directory, or their content pasted into a new file.

Cause.  I guess the missing header files are the  #include “something.h” type?  If so, not often necessary on Arduino, making it easy to forget they exist.  If the project is copied later, say going from version 1 to version 2, or moving to a different machine, only the .ino is taken and the equally important .h files get left behind.  You can guess how I know!

Dave

On 30 December 2024 at 12:29 James Alford Said:

Oh, well. Back to the drawing board. I tried these and recovered the elapsedMillis library, but the others remain elusive. I suspect that they came with some timer codes that I copied from an on-line project on which I based my code. Sadly,  the site from which I copied them is no longer working.

Regards,

James.

Try putting the defunct website url into the internet archive Wayback Machine.
https://web.archive.org/

They may have captured it.

Robert.

Hi James, the screenshots have me flummoxed because they look correct.  Appears you’ve got the file and directory locations right, which is good, except it still doesn’t work!

I’ll have a look at how the Arduino IDE adds libraries to the compiler’s search list.   Might be done by the installer, in which case moving the libraries manually may may have missed a step.  May take a while, I’m unwell this morning.

If you fancy a go yourself, try setting the “Show verbose output during compile” tickbox, which is in  File->Preferences->Settings.   After that Verify the sketch and wade through the output looking for the library loads.   Comparing a successful #include with a unsuccessful #include may reveal the answer.   Unfortunately the log is huge, and written in techno-terse!   Look for lines containing the word library.

Might give the answer, but I have more hope that an internet search for “manually install Arduino library” will provide the answer – the missing step.

Just in case anyone reading this thinks Arduino is always this complicated, not so.  James has an unusual problem that’s forced us to open the bonnet and take the engine apart…    Rarely necessary!

Dave

On 1 January 2025 at 16:41 James Alford Said:…

I then wrote my requirements long-hand and pasted them into ChatGPT. A few seconds later, it had written the code, explained how to connect the components required to make it work and given an explanation of how the code works. The code then complied seamlessly.

I was impressed, but frustrated that I could not find the cause of the problem.

…

This news should have us all trembling in our boots.  As far as I  know this is the first time that an Artificial Intelligence has beaten this forum to the answer!

Thanks for letting me know – had to put the problem aside due to poor concentration earlier and was gritting my teeth for another go.

Dave