README.md
Pixels Camp PCB Badge

Info

This is a PCB badge for the 2019 edition of pixels camp. The project consists on a 39x9 (351) LED matrix display driven by the IS31FL3741 IC and controlled by an ESP32, making it wifi-connected. The board can be powered by usb and/or a 1s lipo battery (charges with usb).

The main goal is to make a web connected scrolling text display, although anyone can develop a custom version of the firmware.

Special thanks to ISSI for supporting the project by supplying a devboard for the IS31FL3741 IC, much apreciated!

Updates

Latest Updates


Working on the firmware (freeRTOS?)
Working on new control board design


Known Bugs


Swapped pins on the regulator footprint


Fixed in new version (added an aditional regulator)

USB-to-Serial (CH340G) needs external oscillator


TODO


Fix bugs
(Add a boot switch for convinience)
Test LED Matrix with devboard


Circuit and PCB

Circuit

Power

Power is supplied by usb and/or 1s lipo, with usb charging capabilities.



The circuit can be powered by usb and/or 1s lipo. T1 is disabled when usb is present and vice-versa. There is also a main power switch that toggles T2.
An LTSpice simulation is present in the <![CDATA[]]>Simulations<![CDATA[]]> folder.

Used ICs:
* Voltage Regulator: NCP708
    * <![CDATA[]]>Datasheet<![CDATA[]]>
* Lipo charger: MCP73831T-2ADI/OT
    * <![CDATA[]]>Datasheet<![CDATA[]]>

Digital and logic

The microcontroller used is the ESP32 with WIFI and bluetooth built-in. The LED matrix is driven by the IS31FL3741 IC. The usb to serial conversion in handled by the CH340G (with auto-reset DTR capabilities).

Used ICs:
* uC: ESP32
    * <![CDATA[]]>Datasheet<![CDATA[]]>
* USB-to-Serial: CH340G
    * <![CDATA[]]>Datasheet<![CDATA[]]>
* LED driver: IS31FL3741
    * <![CDATA[]]>Datasheet<![CDATA[]]>
    * <![CDATA[]]>Dev Board<![CDATA[]]>

PCBs

The PCBs was designed in Altium Designer and the most recent GERBERs and schematics are available in their respective repo folders. The Badge consists of 2 stackable PCBs, one for the matrix and one for the power and logic. Each PCB is 126x36mm and there is a panel PCB with both of the PCBs held by cuttable tabs. The panel is 140x91mm.

IO

Placeholder

Renders

2D




3D