LEAP#191 glowing LEDs on 1.5V
I had a feeling I could cobble together a couple of ideas (Relaxation Joule Thief and RC Oscillator) .. and lo, it works!
As always, all notes, schematics and code are in the Little Arduino Projects repo on GitHub.
Here's a glimpse of the "modified oscillation". CH2 (red) is the LED cathode/transistor collector - as it rises and falls the LED slowly switches off then back on.
For protoboard-based builds I tend to layout the schematic with PAD tools (Pencil-Aided Design) ...