Turning an Arduino Pro Micro Into an ATtiny85 ISP Programmer Using Arduino IDE (2026 Guide)

After multiple failed attempts to program an ATtiny85—including defective parts received from Amazon, missing or deprecated Arduino libraries, and numerous configuration issues—I wanted to document and shared my final, working setup. I tried to capture the exact hardware, wiring, and Arduino IDE configuration I used to program the ATtiny85, and I hope it helps someone else avoid my same frustration in the future.

Core Parts (required)

1. Arduino Pro Micro
2. ATtiny85
3. Breadboard
4. Jumper wires (6–8 male-to-male wires)

Electrical Must-Haves

1. 10 µF electrolytic capacitor
2. Between RESET ↔ GND on the Pro Micro
3. Prevents auto-reset while programming
4. Value range: 4.7–47 µF works
5. 0.1 µF (100 nF) ceramic capacitor
6. Between VCC ↔ GND on ATtiny85
7. Decoupling capacitor (for stability)

Optional (recommended)

1. LED + 220–1kΩ resistor

1. Install the latest Arduino IDE
2. Launch it

1. File → Preferences
2. In Additional Boards Manager URLs, add:

https://raw.githubusercontent.com/sleemanj/optiboot/master/dists/package_gogo_diy_attiny_index.json

1. Click OK
2. Tools → Board → Boards Manager
3. Search “attiny”
4. Install DIY ATtiny by James Sleeman

1. Tools → Board → Arduino Leonardo (Pro Micro uses the same MCU)
2. Tools → Port → select your Pro Micro
3. Modify the ArduinoISP example or use the file bellow
4. File → Examples → 11.ArduinoISP → ArduinoISP AND Update the the following lines

1. Use provided file
2. Upload
3. Install 10uf capacitor to prevents auto-reset while programming Attiny85

Tools menu must match exactly

1. Board: ATtiny85 (Tools → Board → DIY Attiny → Attiny85 )
2. Port: Tools → Port → select your Pro Micro
3. Processor Speed: 8MHz Internal Oscillator(recommended)
4. Programmer: DIY ATTiny: Arduino as ISP (ATmega32U4)

Tools → Burn Bootloader (Do this once per clock change)

Open your sketch

Sketch → Upload Using Programmer (LED Blink test below)