Solar Joule thief problems

[GadgetBoy]

I'm trying to integrate a solar panel and dusk sensor into a bigclive style Joule thief, but I'm running into some issues. To my knowledge (which is admittedly limited), this *should* work, but it isn't. The parentheses on the schematic are the second set of values I tried.

Sent from my ONEPLUS A3000 using Tapatalk


Edit: I'm not integrating a 'dollar' panel. Stupid autocorrect.

[oPossum]

It requires a fast rise time of the power supply voltage to start oscillating. Your circuit will increase the voltage gradually, so it won't start oscillating.

[GadgetBoy]

It requires a fast rise time of the power supply voltage to start oscillating. Your circuit will increase the voltage gradually, so it won't start oscillating.

Well, the Joule thief part works just fine. When I add in the dusk sensor, it doesn't work.

Sent from my ONEPLUS A3000 using Tapatalk

[oPossum]

It doesn't work with the dusk sensor because the voltage rises slowly. When you connect the battery directly the voltage immediately rises to the battery voltage.

[oPossum]

A Schmitt trigger implemented with a PNP & NPN transistor may work. The positive feedback will cause the voltage to rise quickly.

[GadgetBoy]

A Schmitt trigger implemented with a PNP & NPN transistor may work. The positive feedback will cause the voltage to rise quickly.

Ohh. I get what you're saying. I'll try this.

Sent from my ONEPLUS A3000 using Tapatalk

[oPossum]

This may work. R3 provides positive feedback that should make it turn on quickly.

[GadgetBoy]

This may work. R3 provides positive feedback that should make it turn on quickly.

Ooh, nice schematic. I'll whip it up and let you know.

Sent from my ONEPLUS A3000 using Tapatalk

[GadgetBoy]

This may work. R3 provides positive feedback that should make it turn on quickly.

Well, the Joule thief turns on, but it doesn't shut off when the solar panel is illuminated. My mind is mush, though, I might have buggered something. I'll check it over in the morning.

Sent from my ONEPLUS A3000 using Tapatalk

[Zero999]

This may work. R3 provides positive feedback that should make it turn on quickly.

Well, the Joule thief turns on, but it doesn't shut off when the solar panel is illuminated. My mind is mush, though, I might have buggered something. I'll check it over in the morning.

Have you checked the solar panel is actually working?

What open circuit voltage does it produce, when fully illuminated?

[Wolfgang]

Hi,

some time ago I made a competion for different Joule thieves. Look here:

https://electronicprojectsforfun.wordpress.com/energy-harvesting/

Maybe you can use some results.

[GadgetBoy]

Ok, after a good night's sleep, I figured out where I was messing up the wiring. It works perfectly, thanks!

https://youtu.be/j_PFQ7iaptQ 
/\
 | Video of it in action.

[oPossum]

Excellent! Thanks for letting us know it works.

You may be able to reduce power consumption a little by increasing the value of R1 and R3. It is important that the R1:R3 ratio be about 1:2 to have the proper turn on / turn off thresholds. So R1=2k2 R3=4k7, R1=4k7 R3=10k, etc...