Teensy Hardware Key logger

I was at Phrecknic14 in Nashville and watched Irongeek’s talk on his PHUKD device. I remember him saying he wished he had made a key logger using a teensy but hadn’t had the time yet. So I took it upon myself to do it while in Michigan. I had never used a arduino or teensy, and on a super low budget I coupled this project together from thin air almost and nothing but the internet.

Lots and Lots of Logs

This is a example of the log file as the end result.

This is what the log file [ENTER]
like.essays could kill your teensy XP[ENTER]


  • Teensy 2.0
  • Sdcard adapter
  • PS2 Keyboard
  • Micro usb to full usbCable

SD for everyone?

Attach your sd adapter to you teensy 2.0. This is pretty easy, just look at the top of your teensy then place the adapter on top with the sd card pointing toward the usb connector and solder it on. If you have the Teensy++ you will have to use different pins listed on pjrc.com.


I soldered pins on the bottom then a dip socket on top. Then added pins on the bottom of the sd adapter. So it all plugs together.

I own all your keys!

Attach your keyboard to your teensy using the pinout listed on PJRC

I attached the data pin to 9, and the IRQ to pin 8 on my teensy.


I used some extra wire, and some easy pin connectors things that I ripped out of some old computers to connect the keyboard.
The code:


I used the PS2Keyboard Library to interface with the keyboard, then used the Teensy’s HID device library to convert ps2 keys to usb keys. Then I used the SDFat Library to write the keys to the sdcard.


Test it!

Cram it inside the keyboard and give it to a friend. 🙂


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