< !!! NEED TO MODIFY !!! >

A week ago I decided to make an uninterruptible power supply for RPI3. In case when the external power supply fails, Raspberry UPS must provide proper shutdown of RPI3.

As a power source I use two types of batteries - a lithium LSH20 and a lithium polymer battery for which a charge circuit is provided. They can be used together or separately (to choose from). The advantage of the lithium battery is a wide temperature range.

I chose a Atmega328p microcontroller as a control unit and as a result - device is completely Arduino compatible.

Raspberry and Raspberry UPS will be communication through the USB B socket (VCP) and I will try to implement a NUT protocol

Picture below expalins how this UPS have to connect to RPI3:

Feauters:

• Atmega328 microcontroller;
• LSH20 and Li-Po batteries;
• TPS61030 boost converter;
• designed for use in wide temperatue range;
• USB-UART converter;
• operates with standart USB cables;
• battery test circuit;
• fuse protected;
• temperature sensor LM75;
• 2 user leds and 1 button;
• custom enclosure.

Project status :

• Ordering the boards -= PASS =-
• Soldering the device -= PASS =-
• Testing the device -= PASS =-
• Creating the new revision -= work in process... =-