• Green light for pcb layout

    5Volt-Junkie02/08/2019 at 18:49 0 comments

    The schematic is almost done. Just need to add some information to part properties. Now I can start with the PCB design. The dimensions of the board will be about 100x70mm big (3.9x2.76inch).

    I already ordered a couple of components, because I had to create some libraries and it's also a good feeling to having some real components while working on the project :-)

  • Starting with power

    5Volt-Junkie01/27/2019 at 21:35 0 comments

    Started with the power management today. A couple of month ago, I found a very interesting ic from ST, the SRC0. It's a small on/off controller, which can be connected to a SMPS, so the power supply can be enabled / disabled by a simple press of the push-button. Furthermore it has an input for external signal, to disable the power (e.g. from microcontroller).

    For the SMPS I would like to use the TI TPS63001 buck-boost converter. It provides a fixed +3,3V voltage output @ >1000mA current output (Vin = 2.6 - 4.2 VDC).
    In this voltage range and at ca. 100mA load, the efficiency stays >90%, which is not so bad :)

    For the charging circuit I'll use MCP73831. The circuit will be powered by 1 LiPo cell.

  • Start

    5Volt-Junkie01/26/2019 at 23:33 0 comments

    After playing around with the first Prototype of LoPSy (LoRa Paging System ;-) ) and the first range test went well, I wanted to start with a new hardware revision.

    The first hardware prototype contained a Nokia display, AI-Thinker Ra-02 433 MHz LoRa module and an ATmega328 µC. 

    For the new hardware revision I would like to replace the mentioned components and add few more functions.

    Some requirements:

    • SMPS instead of linear regulator
    • 1-cell LiPo charger IC
    • ATSAMD21 microcontroller (compatibility with Arduino Zero MKR (and Adafruit Feather?))
    • Get rid of the Nokia Display
    • uSD-card
    • tiny pager motor
    • buzzer
    • to be defined...