
Constructing an ATtiny85 breakout board for prototyping and testing.
While working on the oven heater control circuit for the Voltage Reference Quad Project V2, I needed a small board for testing the PID heater control without using a serial port or display. I also wanted to use the same board design for multiple projects where I only needed a few I/O pins.
The ATtiny85 (PDIP) breakout board includes an array of 5 low current blue LED’s that are solder jumper selectable for each of the ATtiny85’s I/O pins except for the reset pin.
I also added several wire or 0.1″ header connections for all I/O pins and the power and ground pins. The board also has a power filtering capacitor, green LED power indicator, and a reset pushbutton.
Switch for the reset pushbutton is an Omron B3F-3150 right angle tactile model, but any of the B3F-31XX series will fit. Resistors and LED’s are 0603 size, capacitor C2 is 0805 and C1 is a 1206 size polarized package.


Board dimensions are 0.95 x 0.87 inches (24.00 x 21.97 mm)


Three boards from OSH Park shipping to a US address currently costs $4.05 USD. I did not include any mounting holes in the design, but it should be easy to modify the board to include a mounting point depending on the need.
Eagle CAD V7.7.0 tiny85.zip files.