ArmaLamp - Armageddon resistant night lamp

Plastic covered photo cells + Supercapacitor with unlimited life

Similar projects worth following

- 6x BPW34 photodiodes aka solar cell
(plastic diodes, more resistant to damage against glass solar cell)

- Up to 20F supercapacitor
(You can use bigger capacity but 20F is optimal for charge in one sunny day)

- 4 hours operation in night depends on intensity

- Auto night on

- Step up converter effective use all stored energy, discharge scap until 0.3V !!!!!!

- Output is activated in night

Supercapacitor is charged via Schottky diode,  this current also disable step up booster,
In night or if it lose power booster is automatically started and very effectively discharge
supercapacitor and convert almost all stored energy because can work until 0.3V

Operation TEST

Some assembled pictures:

Circuit is extremely simple to make it reliable.

Portable Network Graphics (PNG) - 32.36 kB - 04/28/2022 at 07:31


Portable Network Graphics (PNG) - 10.39 kB - 04/28/2022 at 07:31


sch - 601.33 kB - 04/28/2022 at 07:31


brd - 72.82 kB - 04/28/2022 at 07:31


  • 6 × BPW34 Opto and Fiber Optic Semiconductors and ICs / Photodiodes
  • 1 × MCP1640 Power Management ICs / Switching Regulators and Controllers
  • 1 × 4.7uH
  • 1 × 10F 3V Supercapacitor
  • 1 × 10mm White LED

View all 9 components

View all 4 project logs

Enjoy this project?



Bgwiz wrote 06/21/2022 at 22:26 point

In your Schematic I see a 10uF capacitor on the output but it is not listed in the BOM/Components. 

You also have 4 resistors shown in the Schematic but only three in the BOM/Components.  Is R3 needed?

  Are you sure? yes | no

bobricius wrote 06/23/2022 at 21:49 point


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Bgwiz wrote 06/21/2022 at 21:35 point

I see that the MCP1640 comes in 4 flavors - MCP1640/B/C/D but neither the BOM(Components) nor the Schematic is clear as to which one it is. 

The image with it showing has CJKK for the marking (great pictures!), but the MCP1640 datasheet only shows that package being marked with a Bxxx (Page 21). 

Are you using the MCP1640T-I/CHY, MCP1640BT-I/CHY, MCP1640CT-I/CHY, or MCP1640DT-I/CHY?

  Are you sure? yes | no

bobricius wrote 06/23/2022 at 21:51 point

No idea, found in my old inventory last 5pcs. currently worldwide sold out. I go to redraw to MAX1724

  Are you sure? yes | no

zanzeoo wrote 06/19/2022 at 09:45 point

Sorry , but i'm a bit confuse about the theory of this schematics , i may be wrong but how can you charge a 10F in less than 24 hours with such current ?. According to the datasheet BPW34 source only 50µA ? . Can you explain more your theory . Because i found a total charge in 4days. Thanks

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bobricius wrote 06/19/2022 at 21:35 point

short current from BPW34 is about 4mA, it can charge 20F in sunny day without problems.

  Are you sure? yes | no

zanzeoo wrote 08/04/2022 at 16:14 point

OK, can you tell me more about R3 , are you charging the cap throught it ? 1M ?

Is the cap is 100 or 10 Farad , How long last the led ?

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zanzeoo wrote 08/04/2022 at 16:27 point

How does flow the current from the solar led , From K to A ?

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Liam Plybon wrote 06/09/2022 at 05:10 point

I would love if this fit in a standard light bulb form factor, disconnected from mains. A wonderful solution to exterior lighting light pollution at night! 

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Michael.kadonoff wrote 06/08/2022 at 17:17 point

that fine balance between the MCP's minimum turn on and the diode's conduction voltage when charging the cap is elegant.

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dougal wrote 05/06/2022 at 18:28 point

What is the approximate cost for all of the parts?

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ian wrote 06/10/2022 at 14:49 point

BOM cost looks to be about $15-20 (plus shipping) for single quantity.

  Are you sure? yes | no

ross wrote 05/05/2022 at 20:01 point

Brilliant idea. Could a switch be safely inserted in to the circuit to allow charging but not turn the light on when it got dark? Allowing you to store the 4 hours of power for when it was needed? I understand the realiabilty reason of not including one but I was thinking reed switch? 

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bobricius wrote 05/19/2022 at 09:33 point

I try add switch in next release

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Matthew Loser wrote 05/05/2022 at 19:26 point

Help an amateur out here! I am thinking this is something even I could build. I would love to hand them out to people for kicks (my thinking is to do what upstageleft suggested and cast it in resin--clear bubble on top and dark cylinder below. But how do I go about ordering the PCBs for this? I am in the US and have searched for a few sites, but am not sure how to configure what I want. 1 layer or 2? And THEN it gets harder. :)

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bobricius wrote 05/19/2022 at 09:34 point

testing smaller boards,  put in resin is possibly but I have no experiences with resins

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teraz wrote 05/05/2022 at 11:06 point

is possible add mirror/metal top outside tile? or meybe normal reflector.

or add

or add "Forever Torch" Flashlight Just Shake old idea.

 for enclosure i rather prefer

  Are you sure? yes | no

Benji Greig wrote 05/05/2022 at 01:55 point

Great idea  @upstageleft. Totally agree. Would be keen to make a few of these for where I live as we have power go whenever big storms happen.

  Are you sure? yes | no

upstageleft wrote 05/04/2022 at 23:25 point

Rather than a sample jar, have you considered casting in clear resin? Also, you could put a neodymium magnet at the base and make it a throwie (or just easily mountable). Seriously, I would buy a bunch of those...

  Are you sure? yes | no

bobricius wrote 05/19/2022 at 09:35 point

it is possibly but I have no experiences with resins

  Are you sure? yes | no

Luís Carlos wrote 04/30/2022 at 21:09 point

A beauty PCB :)

Why D5?

  Are you sure? yes | no

bobricius wrote 04/30/2022 at 21:13 point

through D5 is capacitor charged and also disabling power supply booster

  Are you sure? yes | no

deʃhipu wrote 04/29/2022 at 08:29 point

Very illuminating!

  Are you sure? yes | no

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