After spending some time on field tests of the solar lamps, I redesigned the PCBs to improve a few things, this is a quick summary…

The main reasons why I wanted to update the design between the 1st and 2nd production batches are the following:

  • Drive LED in ‘Sink’ mode, since the ATTiny43u can sink a bit more current than it can source, so the LED is brighter
  • Simplify the switch circuit by using the internal pullup (saves one component)
  • Reduce PCB size significantly and use AAA batteries. The lamps still last almost two days with a single battery, more than we need.

The revised PCBs got here this week, and the new lamps are working great. Final component selection is identical to previously. Current consumption is 28mA with the LED fully lit which is pretty OK.

Final lamp circuit

The final circuit is a lot more compact than the first prototype, which means you can mount it in a larger variety of enclosures.

The first few prototypes are working great and are much smaller than v1.0, as can be seen below!

The first v2.0 lamps

Version 2.0 Schematics

Version 2.0 Schematics are as follow:

V2.0 Schematics

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