Re-programmable 8×8 LED Matrix

An ATTiny85-based LED Matrix “backpack” PCB design.

Back of PCB

Easily re-programmable, low-cost BOM, simple construction, and tons of fun! This small PCB fits to the back of an LED Matrix and drives animations.

Front of PCB

At the heart of the design is an atTiny85 microcontroller. It holds the animation and library to drive the matrix. In addition, a MAX7219 LED driver is used to interface with the matrix.

Matrix when off

Animations can be uploaded over USB and programmed in the Arduino IDE.

Want to build it yourself!? EAGLE schematic and board layout can be found below.

Parts:

  • 1x ATTiny85 Microcontroller (SMD)
  • 1x MAX7219CNG (THT)
  • 1x 8*8 LED Matrix (I used the LTH1388BSR)
  • 2x 3.6v Zener Diode (for USB Bus)
  • 1x MicroUSB Connector (SMD)
  • 1x 6mm Tact-switch (SMD)
  • 2x 68 ohm resistor (0805)
  • 1x 30k ohm resistor (0805)
  • 1x 1.5k ohm resistor (0805)

Files:

LCD Inverter Add-On

A micro-board add-on to an LCD screen inverter to allow for MoBo-less control.

A small (30mm x 10mm) PCB designed to be placed on top of a specific laptop LCD inverter board. This board is designed to fit within the footprint of the existing connector and ground screw pad. The board layout and schematic can be modified to fit other inverter models.

By using this design, one can reuse a laptop backlight for other purposes without needing the original computer’s motherboard. The board facilitates dimming and on/off functionality. Backlights can be used for cheap lighting, or for tracing images between pages.

EAGLE schematic and board layout can be found below, Arduino code as well.

Parts:

  • 2x 6×3.5mm tact switches
  • 1x 0603 capacitor 10uF or 100uF
  • 1x 0805 resistor 10k
  • 1x AtTiny13a or AtTiny45/85 etc.
  • 1x SOT89 linear regulator 5V such as 78L05F

Files:

EAGLE Schematic: LCDInverterSCH-Rev1

EAGLE Board: LCDInverterBRD-Rev1

Board PCB: LCDInverterPCB-Rev1

Code: LCDInverterCode-Rev1