Sunday, 17 March 2013

Arduino Honeymoon Over

After a long and enjoyable honeymoon period with the Wotduino, in which she could do no wrong, I woke up this morning to see her for what she is - warts and all...

The problem was that I had made some modifications to the code (what the Arduino community call the "sketch") for my little QRP Rig and I had committed the ultimate sin - I hadn't saved it!


Go ahead - laugh at me. Call me all sorts of names. Tell me I should never do that.

Fact is - any other IDE for a micro-controller I've ever worked with (as far as I can remember) saves the code when it is built. So, naively, I expected Arduino would do the same. The sort of assumption you are likely to make in the first flush of romance!

No sir! Not the Arduino!

Turns out that this is a weakness which trips up many newcomers - a quick search on the net returns reassuring comments like "Lots of people ask this. Quick answer - no." (on the Arduino forum, no less). Fortunately, the quick answer is that its IS possible to recover code that has been uploaded to the Arduino, even when you didn't go through the stone-age step of saving the sketch at the time (or even when you closed the Arduino IDE).

I was put onto the scent by Robert's useful post, which had me searching for a folder of the form "buildxxxxxxxxxx.tmp" and which, in my case turned out to be:


You need to remember the (approximate) date at which it was created / modified to find out which is the correct folder.

Then you look for the file with the same name as your sketch and a C++ extension - in this case, the file highlighted...


Opening this file (in Notepad, if on a windows machine) will reassure you that you're on the right track...


Then, it can simply be copied and pasted back into the Arduino editor window where it belongs...


Here I changed the name of the sketch and made damned sure to save it - I won't be going through this fiasco again!

So - there IS a way to rescue all your typing and escape the disappointments and inadequacies of the Arduino "Development Environment". Perhaps she's worth sticking with for a little while longer!

...-.- de m0xpd


  1. Nice write up, I still can't get over "Lots of people ask this. Quick answer - no." and people accepted this and never went looking for the lost code.

  2. Thank you for the tip about opening with notepad for Arduino, you saved me hours of headache!