Cheap casing with solar & battery for less than 4$

[lacco]

Hi everyone,
I was looking for a cheap case for an outdoor ESP project - I want to record temperature, humidity, air pressure (and the battery voltage).

What I found was this solar led light, which comes already with a small solar cell and a 1.2V battery at a very cheap price: https://de.aliexpress.com/item/1Pc-6LED ... 01160.html
Only downside i can see at the moment is that its not waterproof, so it should be placed under a roof.

Here's a picture from the opened case:

solar.jpg

Here's an explanation how the circuit works (it uses a 5252F integrated circuit): http://artists.scitoys.com/three_volts

Could someone from the electronics experts let me know whether I can use this circuit (probably with an added capacitor) to also power the ESP, or would I need a seperate step up converter? I would guess that this circuit does not provide enough current.

[MiKa1975]

Hi,
something for inspiration: https://www.openhardware.io/view/281/So ... -Harvester
Regards,
MiKa

[krikk]

could this be solved with a cheap step up module from aliexpress??

[lacco]

Thanks for your replies.

I could not yet find a step-up/boost converter that I can use here.
The one posted above needs input voltage >2V and all the other ones I've found (e.g. https://www.aliexpress.com/item/1-5V-1- ... 31883a9880) seem to provide not enough current (in this case, <50mA) at such low input voltages (1.2V or less)

Any other ideas how to provide enough current (>150mA) at 3.3V from a single 1.2V battery?

[ipua]

Here is one more - step up from 0.8V

[lacco]

I've tried similar ones and it didn't work, because these things do not provide enough current for the ESP (e.g. this one provides only 10 mA @ 0.8V)

[Shred]

Waking an old thread in case it helps someone out.

There are quite a few solar garden lights available now that use a single 3.6v LiFePO4 cell instead of an NiMH cell (or two). These are ideal for running an ESP8266 module. I've had a hacked Wemos D1 Mini running from one for a while now. I say hacked, because I needed to disconnect the output of the 3.3v regulator and two pins on the CH340G USB controller to get the deep sleep power consumption down low enough (about 50 uA).

This is a very similar looking light to the one I bought (it may not have the same internals but looks identical):
https://www.kogan.com/au/buy/4-pack-sol ... lsrc=aw.ds

Notes:
* The 3.6v cell is only 300mAh - you can get higher capacity, but I haven't needed to.
* The case is mostly metal, so best to house the ESP8266 in a separate plastic case.
* Don't forget to disconnect the LED and PIR in the housing, so they don't flatten the battery
* The PIR is _very_ trigger happy and will keep turning the light on and off all night in response to leaves moving, wild animals, cosmic rays, the phase of the moon or whatever sets it off when nothing seems to be happening!

Others may be able to find better solar garden lights with a more useful housing.

[helio58]

There are quite a few solar garden lights available now that use a single 3.6v LiFePO4 cell instead of an NiMH cell (or two). These are ideal for running an ESP8266 module. I've had a hacked Wemos D1 Mini running from one for a while now. I say hacked, because I needed to disconnect the output of the 3.3v regulator and two pins on the CH340G USB controller to get the deep sleep power consumption down low enough (about 50 uA).

Hi Shred,
Do you have any pictures of the disconnect output regulator and two pins on the CH340G ?