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A project log for MAST Cell for Wildlife Research

(M)iniature (A)rgos (S)atellite (T)racking Cell for Wildlife Research

Daniel HeDaniel He 07/21/2021 at 11:013 Comments

Commit 13a81ae

First prototype. Based on the reference design provided by Arribada. RF traces are calculated with JLC2313 stackup. PCB manufactured by JLCPCB.

Assembled board weighs less than 2g.

What worked:

- Microcontroller

- Power regulators / switch

What didn't work:

- Solar charging

- SPI flash

Apparantly, the "optional" MPPC function on the solar charger IC was not so optional after all.

I also messed up the symbol for the flash chip. The datasheet listed the BGA balls bottom-up, I assumed it was top-down.

Discussions

Simon Merrett wrote 07/22/2021 at 06:31 point

Hi Daniel, this is an interesting project - thanks for logging it! I feel for you ref the BGA diagram - I do that sort of thing all the time. What solar cells are you using?  

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Daniel He wrote 07/23/2021 at 13:29 point

I ordered some custom cells trimmed to the same dimensions as the PCB so they can be directly soldered to the back in the final product. Specs are ~1.8V open circuit, ~20mA short (best case scenario).

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Simon Merrett wrote 07/23/2021 at 14:16 point

Oh nice, looking forward to seeing them. Where did you order custom cells from? 

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