My recent two blogs on powering a flasher with four red LEDs used a flasher made by modifying a Joule Thief. It works fine, but it requires a toroid core and wire; the flasher I blogged earlier does not require any inductor. It is a switched capacitor or charge pump,. and it works okay with two transistors. It also has a daylight sensor that shuts it off during daylight hours.
What I have to do is put it on a Farad capacitor, charge the cap up to 1.5V, and see how long it will flash. I’m aiming for 7 or 8 hours, so it will get through to midnight during the winter months when days are short.