Keypad Library Compatibility
Scan matrix keypads with debouncing and key states.
- Pinned version
- 3.1.1
- Last matching compile evidence
- 2026-10-25
- Toolchain
- avr-gcc-wasm@0.2.0
- Primary headers
- Keypad.h, Key.h
Dependencies and practical limits
Scan matrix keypads with debouncing and key states.
Matrix row/column pin arrays must match the wiring and selected board.
Switch topology and debounce affect observed input; a successful link does not prove a physical matrix is wired correctly.
No additional catalog dependencies are required.
For a missing header, first compare the include to the example below. For an undeclared identifier, inspect the first diagnostic and selected board rather than changing every library version.
Board compile matrix
These are recorded compile/link results for the current build and exact source hash. UNTESTED means no matching proof, not an assumed pass. Memory values belong to the listed example and exclude runtime stack/heap or dynamic buffers.
| Board/profile | Result | Flash bytes | Static SRAM bytes | Last tested |
|---|---|---|---|---|
| Arduino Uno R3 — ATmega328P | PASS | 3922 | 327 | 2026-10-25 |
| Arduino Nano V3 — ATmega328P (new bootloader) | PASS | 3922 | 327 | 2026-10-25 |
| Arduino Nano V3 — ATmega328P (old bootloader) | PASS | 3922 | 327 | 2026-10-25 |
| ATmega328PB — 16 MHz | PASS | 4134 | 327 | 2026-10-25 |
| Arduino Mega 2560 — ATmega2560 | PASS | 4682 | 327 | 2026-10-25 |
| Arduino Leonardo — ATmega32U4 · native USB | PASS | 6406 | 293 | 2026-10-25 |
| Arduino Micro — ATmega32U4 · native USB | PASS | 6408 | 293 | 2026-10-25 |
| Arduino Pro Mini — 5 V · 16 MHz | PASS | 3922 | 327 | 2026-10-25 |
| Arduino Pro Mini — 3.3 V · 8 MHz | PASS | 3910 | 327 | 2026-10-25 |
Build: e0f6d304cce4ae0a0989a9b1300cbc1a21a595e5e3e7f57ed0ab3468ecf7940b. Library source hash: efae8c87f9d2fe1471a6fb9ba74ec0b0ee3ce51b6771621b3580ffffd880f259. Compilation does not certify physical peripherals, timing or USB upload.
Keypad example
This is the actual pinned example available in Circuitera. Pin choices and wiring in a general example use Uno unless otherwise stated; review the selected board reference for other targets.
#include <Keypad.h>
const byte ROWS = 4, COLS = 3;
char keys[ROWS][COLS] = {{'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'}};
byte rowPins[ROWS] = {9, 8, 7, 6};
byte colPins[COLS] = {5, 4, 3};
Keypad keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
void setup() { Serial.begin(9600); }
void loop() { char key = keypad.getKey(); if (key) Serial.println(key); }
Projects using Keypad
No validated public tutorial currently uses this library. The example demonstrates compilation; no working simulator peripheral or hardware project is implied.
Upstream source and documentation ↗
Pinned source archive (3.1.1) ↗
Read the test methodology →