DIY Macro Keyboard (DigiSpark)




In this Instructables i will use a DigiSpark with a CD4021 Shift Register and read 6 mechanical switches.

Depending on the switch pressed, the DigiSpark will send some key strokes back to the PC. Making a sort of a Macro keypad, where we can assign each tactile switches to send key stroke.

Key Features :

• Programmable keys
• Shortcut keys With one press of a button.
• Volume control keys (for windows)

Step 1: Parts List

  • 1x Digispark (Ebay).
  • 1x CD4021 Shift register . ( Ebay)
  • 16 pin IC socket
  • 1x Tactile Momentary Switches (Ebay)

(mechanical keys) (Ebay) (Banggood)

  • 10K resistors. (number of resistors depend on the number of switches used)
  • Micro USB cable or USB-to-USB cable Depends on type of digispark.

Step 2: Tools

  • Soldering iron
  • Breadboard
  • wires
  • jumper wires
  • Prototyping board
  • Wire strippers /cutters
  • USB cable ( depends on the type of the digispark model)
  • Multimeter

Skills required:

  • Basic soldering skills
  • Basic programming skills

Step 3: Digispark (Software Config)

The Digispark is an Attiny85 based microcontroller development board similar to the Arduino line, only cheaper, smaller, and a bit less powerful. IT use the familiar Arduino IDE the Digispark is a great way to jump into electronics, or perfect for when an Arduino is too big or too much.


  • Support for the Arduino IDE 1.0+ (OSX/Win/Linux)
  • Power via USB or External Source - 5v or 7-35v (automatic selection)
  • On-board 500ma 5V RegulatorBuilt-in USB (and serial debugging)
  • 6 I/O Pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB)
  • 8k Flash Memory

Installing the Digispark Drivers

Make sure to use Arduino IDE version 1.6.7 otherwise uploading error will occur.

Watch this video to learn how to install Digispark drivers (That is created by Brainy Bits)

the Best Tutorial that i found. check their site for more information

And Check this link to learn how to connect and program the Digispark using the Arduino IDE



Make sure to use Arduino IDE version 1.6.7

Because i got avr errors when uploading the code.

Arduino IDE

Step 4: Connections

Pins Connections (digispark to shift-register)

• Digispark GND -------------- CD4021 GND/VSS
• Digispark 5V/VCC ---------- CD4021 VCC/VDD

• Digispark (P2 , D2) --- CD4021 LOAD / (pin 09 )

• Digispark (P1 , D1) --- CD4021 CLOCK / (pin 10)

• Digispark (P0 , D0) -- CD4021 SER OUT / Q8 / (pin 03)

Tactile Buttons (8 switches)

One leg of the Tactile Switches/ mechanical switch is connected to the 5V line.

The other leg of the Tactile Switches/mechanical switches are connected to pin 1-2-3-4-5-6-7 of the CD4021.

Pins 1-2-3-4-5-6-7 also have some 10K resistors connected to ground for switch pullups.

Look At the circuit layout for further clarifications.

Step 5: Soldering

The parts were soldered on piece of perfboard that will fit in my enclosure .Just follow the circuit diagram in the above step.

Step 6: Enclosure

The plywood parts were laser cut and I used wood glue to glue the parts to form the enclosure.

Step 7: The Test Code

Check step 4 to learn how to install the libraries.

Before verifying the code , change the board to Digispark default .this will the ensure that the Digikeyboard.h is present in Arduino IDE . otherwise the digispark libraries are not present in the IDE even though its installed properly.

Each button has its unique binary value depending on the CD4021 pin , therefore to find out which is which upload this test code to the digispark

open the notepad and press the buttons and check the output.


Upload this code.

To have the DigiSpark act as a Keyboard, we will be using a library called “DigiKeyboard” created by DigiStump.

Check the PDF file to find out the Arduino key word for each keyboard key.

To send a key stroke this command is used.


To print something like "hello" this command is used.

DigiKeyboard.print ("Hello");

To put a delay this command is used:


To press two keys at once :

separate the two key commands with a comma


DigiKeyboard.sendKeyStroke(KEY_C , MOD_CONTROL_LEFT);//copy shortcut (ctrl +v).
DigiKeyboard.sendKeyStroke(KEY_L , MOD_GUI_LEFT);//windows lock shortcut  (windows logo key + L)
  • On the keyboard the key that is pressed second should come before the comma. for example in the copy shorcut the "C" key should be before "control" key. But on the keyboard it should be "ctrl" key then the "c" key.

To press three keys at once:

separate two keys with a comma and the third command with a


(Ctrl + Shift + Enter)

  • Always the the last key that should be pressed must come before the comma. In the above case "ENTER" must come before the comma.

To only press the windows key:

DigiKeyboard.sendKeyStroke(0, MOD_GUI_LEFT );

To execute a command with a single press:

To open "CMD" in administrator mode , assign a key to this code and change the binary value .

if (RegisterValue == B10) 

DigiKeyboard.sendKeyStroke(0,MOD_GUI_LEFT ); // press the windows key
DigiKeyboard.delay(1000); // wait a second
DigiKeyboard.delay(1000); // wait a second
DigiKeyboard.sendKeyStroke(KEY_ENTER,MOD_CONTROL_LEFT | MOD_SHIFT_LEFT ); // Ctrl+shift+enter
DigiKeyboard.delay(1000); // wait a second
DigiKeyboard.sendKeyStroke(KEY_ARROW_LEFT );
DigiKeyboard.sendKeyStroke(KEY_ENTER );

UsefulWindows 10 shortcut keys

After uploading is done , remove the USB cable and plug it back again.

If you receive and error saying the USB is not recognized try unplugging and plugging back it again and while its initializing press any key repeatedly until it works.

Step 9: Code ( With Different Library) #USE THIS #

Download and install this (Adafruit-Trinket-USB) library to your Arduino IDE.

upload the code and change according to your needs.

when using this code no need to press a key when plugin in the cable.

Useful key codes

Example code: This replicate the exit action with a button.


TrinketHidCombo.pressKey(KEYCODE_MOD_LEFT_ALT, KEYCODE_F4);

TrinketHidCombo.pressKey(0, 0); // releasing keyboard.

Step 10: Volume Controls (optional)

To use Volume Control

Download and install this library (Adafruit-Trinket-USB) in your Arduino IDE.

upload this code and change the register value to match the button.

TrinketHidCombo.pressMultimediaKey(MMKEY_MUTE); // mute

TrinketHidCombo.pressMultimediaKey(MMKEY_VOL_UP); // volume up

TrinketHidCombo.pressMultimediaKey(MMKEY_VOL_DOWN); // volume down

Step 11: Final Thoughts

Thanks for reading! I'd love to hear your thoughts.



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    27 Discussions


    Reply 2 months ago

    I looked in the comments hoping for an answer to this and this comment did not disappoint. +1


    Question 2 months ago

    hi, i have try pressing any button after plugin the usb but it still unrecognized, while using other code i just run with out any problem

    14 answers
    tharindurc xmzxmlx

    Answer 2 months ago

    This happens when you are using digikeyboard library?
    I really dont what is problem with the library.That is the reason why i included trinket which has more keycombos than the other.Use trinket library instead.


    Reply 2 months ago

    hi, thank for the reply
    i have try using the trinket library, it now recognized as hid device but it still cannot detect any button press

    tharindurc xmzxmlx

    Reply 2 months ago

    Cannot detect any buttons as in you cant see what is pressed.were you able read the binary values?


    Reply 2 months ago

    yes, i already try the testing for binary value code but it fail to detect the usb

    tharindurc xmzxmlx

    Reply 2 months ago

    I think it is something to do with shift register.Have you tried changing the shift register?
    Im not really sure whats wrong with this, since i never encountered such problem with my build


    Reply 2 months ago

    i have try replacing the shift register with all that i have one by one but the problem still occur. looks like i need to put this project on hold. thanks for your reply

    tharindurc xmzxmlx

    Reply 2 months ago

    Does the digispark work with any other example sketch that are in the library.Try connecting a button to the digispark without using the shiftregister and check if the board is working fine?


    Reply 2 months ago

    i have try using the digikey keyboard and mouse example and it work just fine. the problem still occur with out the shift register.

    tharindurc xmzxmlx

    Reply 2 months ago

    Problem occur as in when you connect a button without the register.Have tried a different board?


    Reply 2 months ago

    yes, it still display error message. i have use 3 different board and it still the same

    tharindurc xmzxmlx

    Reply 2 months ago

    Would you mind posting a photo of the error you are getting.


    Reply 2 months ago

    here are the error message. i have try tested the switch connection using led, and it turn off when i push the button, it is supposed to do that or there are some kind of mistake with my wiring

    tharindurc xmzxmlx

    Reply 2 months ago

    Try reinstalling the digistump drivers and check.Do you get the same error when using the trinket library examples


    Reply 2 months ago

    i have try re installing the driver yet the problem still occur. while using the trinket code the computer are able to detect the board as hid device but when i push any button there are no response


    Question 4 months ago on Introduction

    Hi Tharindurc,
    I'm looking to build something similar to this and this guide has been super helpful. I want to use 8 switches (using PI-1 through to PI-8). Would using PI-8 work or is this reserved for something else? I notice you mention that the switches should be connected to pins 1-7 with no mention of the 8th pin on the CD4021.

    1 answer
    tharindurc Omnipotenti

    Answer 4 months ago

    Hi Omnipotenti
    PI-8 is not reserved for anything, it will work just fine.I could not use it because i was not able to read its binary value.That is the reason i kept it out.

    Try this link,You might need a arduino uno or something similar to read the bin value