Raspberry Pi Pico with LoRa and recharable lithium battery

This is an currently experimental PCB to combine a Raspberry Pi Pico with a LoRa module and an added lithum battery charger as published in LoRa with Rasperry Pi Pico ( Elektor 7/2021 ) and  LoRa mit dem Raspberry Pi Pico ( MagPi (DE) #29 S.76 ).

As for now this PCB and its schematics are in a prototpye stadium and have not been build or tested. So any recreation at your own risk. Schematics and PCB files can be accessed throug the Elektor GitHub Repository, so feel free to clone your own version and modify it as you need.

What is currently included: 

• Mounting option for a Raspberry Pi Pico
• Space for a RFM95 LoRa Transreceiver / Modem
• DS18B20 temperatur sensor
• MCP73871-1CC lithum battery charger
• XB8089D Battery protection IC
• TPS25940x eFuse

The Schematic looks currently like this:



It is devided in two sections, one with the Raspberry Pi Pico , DS18B20 temperatur sensor and RFM95. The second part ist the battery stage with charging and protection ICs. As this is a prototype you can see R21, R20, R18 and R19 beeing 0Ω resistors to disconnect certain parts of the battery stage for closer inspection and individual testing. This also means the PCB look a bit different what a normal PCB would look like.



You can see the two section also on the PCB, designed in a way currently if the battery stage is not working i can be totally removed. We knwo this schematic nor this PCB is perferct and would loke to get your wishes and enhancement suggestions for it. One thing we know we need to address it the standby power this currently uses as he RP2040 can be as low as 180 µA @ 3.3V but the integrated DC/DC converter on the Raspberry Pi Pico will consume 1mA standy by, and this is way to much for a battery opperated device.

After the PCB is ordered and assembled will will give you an update on how things went and what is working and what not, so stay tuned. In the meantime we hope to receive som feedback.