Re: PCB designer? Weight issues.
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After realizing the previous charge controller wouldn't work, I decided to design my own. The schematic and PCB renders are attached. This uses the SPV1040 charge controller - http://www.st.com/en/power-m
The board is very small - only 1 inch X .5 inches. The components are mostly tiny 0603 size - so should be a fun challenge to solder. The IC is 3mmX4.4mm.
The S+/- pads are for the small solar cells. I should be able to use 2 of them in series to make ~1.2 volts. The circuit then upconverts this to 5 volts which charges the supercapacitor (CAP+/-) which functions as a battery (except this one works at -40 degrees). It then routes back to V+/- which will go to the Arduino raw power input. Most of the capacitors and resistors are used to set the controller charge values.
There's also a voltage divider on the output that goes to the A connector. This will allow me to measure the output voltage from the Arduino so I don't transmit or turn on the GPS if the voltage is too low.
Feedback or criticism of the design is VERY welcome. I figure I have around 50/50 odds that I designed this in a way that will actually work. I'll order up some PCBs from OSH Park soon and give it a go.
On Wed, Jun 28, 2017 at 8:06 AM, Jared Smith <jared@...> wrote: