After blowing several LED's on 1.5V using Lasersaber's newest circuit, I decided to try a few things out, that didn't use the pot coil method and with the primary aim of minimizing power needs.
One idea was a simple change to a regular blocking oscillator...to run the LED's in a similar series way as LS does and to incorporate the distanced coil geometry that TinMan showed with his Cool Joule. A pair of 1000uH inductors suited the idea well.
The whole idea of this is to create a very effective scavenging circuit, rather than a flashlight.
Perhaps using several sources, such as heat, vibration, sound, RF and other normal ambient environmental energies.
The result so far, is what I call the Blocking Ringer.
Performance specs:
Using a 1.5V battery and a 100uF cap, the light output run is up to 53 seconds of constant light.
Using a 3300uF cap, the run is 23 minutes.
Using a 'calculator' type solar panel a foot or so away from the bench CFL to charge the 3300uF over 5 minutes, the run is similarly 23 minutes.
(free light energy to charge it up is also appealing)
Here is an 'Unlisted' YouTube video uploaded just now showing such a test run, using a panel from a 'Dancing Flower'.
The measured voltage from the panel is 1.326V.
[youtube]v2b5ejDJxwk[/youtube]
I intend to try an MPSA18 on the circuit and then probably do a public video...got some on order at the moment.
With such a solar panel connected, the circuit kicks on easily in ambient room light. It will fire up fine using the light from a PC monitor and even the light from a single LED solar garden light from several inches away.
Quick video to demonstrate the garden light powering it.
[youtube]R25xT4QOj-A[/youtube]
Attached is the circuit diagram, plus a list of various transistors tried so far using a 100uF capacitor and their run times.
The C1815 'GR' has put in the best results.
All help or comments appreciated