diff --git a/components/modules/CMakeLists.txt b/components/modules/CMakeLists.txt
index 06b2ecaf..e9d0c06e 100644
--- a/components/modules/CMakeLists.txt
+++ b/components/modules/CMakeLists.txt
@@ -25,6 +25,7 @@ set(module_srcs
   "i2c_hw_master.c"
   "i2c_hw_slave.c"
   "ledc.c"
+  "matrix.c"
   "mqtt.c"
   "net.c"
   "node.c"
diff --git a/components/modules/Kconfig b/components/modules/Kconfig
index c393ab6b..f7ea9d0b 100644
--- a/components/modules/Kconfig
+++ b/components/modules/Kconfig
@@ -177,6 +177,13 @@ menu "NodeMCU modules"
         help
             Includes the LEDC module.
 
+    config NODEMCU_CMODULE_MATRIX
+        bool "MATRIX module"
+        default "n"
+	select NODEMCU_CMODULE_GPIO
+        help
+            The matrix module provides support for cheap matrixed keypads like a 3x4 telephone keypad.
+
     config NODEMCU_CMODULE_MQTT
         bool "MQTT module"
         default "n"
diff --git a/components/modules/matrix.c b/components/modules/matrix.c
new file mode 100644
index 00000000..2a90b7e9
--- /dev/null
+++ b/components/modules/matrix.c
@@ -0,0 +1,528 @@
+/*
+ * Module for interfacing with cheap matrix keyboards like telephone keypads
+ *
+ * The idea is to have pullups on all the rows, and drive the columns low.
+ * WHen a key is pressed, one of the rows will go low and trigger an interrupt. Disable
+ * all the row interrupts.
+ * Then we disable all the columns and then drive each column low in turn. Hopefully
+ * one of the rows will go low. This is a keypress. We only report the first keypress found.
+ * we start a timer to handle debounce.
+ * On timer expiry, see if any key is pressed, if so, just wait again
+ * If no key is pressed, run timer again. On timer expiry, re-enable interrupts.
+ *
+ * Philip Gladstone, N1DQ
+ */
+
+#include "module.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "task/task.h"
+#include "esp_timer.h"
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include "driver/gpio.h"
+
+#define MATRIX_PRESS_INDEX	0
+#define MATRIX_RELEASE_INDEX	1
+
+#define MASK(x) (1 << MATRIX_##x##_INDEX)
+
+#define MATRIX_ALL		0x3
+
+#define CALLBACK_COUNT	2
+#define QUEUE_SIZE 8
+
+typedef struct {
+  int32_t character;    // 1 + character for press, -1 - character for release
+  uint32_t time_us;
+} matrix_event_t;
+
+typedef enum {
+  WAITING_FOR_PRESS,
+  WAITING_FOR_RELEASE,
+  WAITING_FOR_DEBOUNCE
+} state_t;
+
+typedef struct {
+  uint8_t column_count;
+  uint8_t row_count;
+  uint8_t *columns;
+  uint8_t *rows;
+  state_t state;
+  bool open;
+  int character_ref;
+  int self_ref;    // to prevent GC at bad moments.
+  int callback[CALLBACK_COUNT];
+  esp_timer_handle_t timer_handle;
+  int8_t task_queued;
+  uint32_t read_offset;   // Accessed by task
+  uint32_t write_offset;  // Accessed by ISR
+  uint8_t last_character;
+  matrix_event_t queue[QUEUE_SIZE];
+} DATA;
+
+static task_handle_t tasknumber;
+static void lmatrix_timer_done(void *param);
+//
+//  Queue is empty if read == write.
+//  However, we always want to keep the previous value
+//  so writing is only allowed if write - read < QUEUE_SIZE - 1
+
+#define GET_LAST_STATUS(d) (d->queue[(d->write_offset - 1) & (QUEUE_SIZE - 1)])
+#define GET_PREV_STATUS(d) (d->queue[(d->write_offset - 2) & (QUEUE_SIZE - 1)])
+#define HAS_QUEUED_DATA(d) (d->read_offset < d->write_offset)
+#define HAS_QUEUE_SPACE(d) (d->read_offset + QUEUE_SIZE - 1 > d->write_offset)
+
+#define REPLACE_IT(d, x)                            \
+  (d->queue[(d->write_offset - 1) & (QUEUE_SIZE - 1)] = \
+       (matrix_event_t){(x), esp_timer_get_time()})
+#define QUEUE_IT(d, x)                            \
+  (d->queue[(d->write_offset++) & (QUEUE_SIZE - 1)] = \
+       (matrix_event_t){(x), esp_timer_get_time()})
+
+#define GET_READ_STATUS(d) (d->queue[d->read_offset & (QUEUE_SIZE - 1)])
+#define ADVANCE_IF_POSSIBLE(d)            \
+  if (d->read_offset < d->write_offset) { \
+    d->read_offset++;                     \
+  }
+
+static esp_err_t set_gpio_mode_input(int pin, gpio_int_type_t intr) {
+  gpio_config_t config = {.pin_bit_mask = 1LL << pin,
+                          .mode = GPIO_MODE_INPUT,
+                          .pull_up_en = GPIO_PULLUP_ENABLE,
+                          .pull_down_en = GPIO_PULLDOWN_DISABLE,
+                          .intr_type = intr};
+
+  return gpio_config(&config);
+}
+
+static esp_err_t set_gpio_mode_output(int pin) {
+  gpio_config_t config = {.pin_bit_mask = 1LL << pin,
+                          .mode = GPIO_MODE_OUTPUT_OD,
+                          .pull_up_en = GPIO_PULLUP_DISABLE,
+                          .pull_down_en = GPIO_PULLDOWN_DISABLE
+                        };
+
+  return gpio_config(&config);
+}
+
+static void set_columns(DATA *d, int level) {
+  for (int i = 0; i < d->column_count; i++) {
+    gpio_set_level(d->columns[i], level);
+  }
+}
+
+static void initialize_pins(lua_State *L, DATA *d) {
+  for (int i = 0; i < d->column_count; i++) {
+    if (set_gpio_mode_output(d->columns[i]) != ESP_OK) {
+      luaL_error(L, "Unable to configure pins");
+    }
+  }
+
+  set_columns(d, 0);
+
+  for (int i = 0; i < d->row_count; i++) {
+    if (set_gpio_mode_input(d->rows[i], GPIO_INTR_NEGEDGE) != ESP_OK) {
+      luaL_error(L, "Unable to configure pins");
+    }
+  }
+}
+
+static void disable_row_interrupts(DATA *d) {
+  for (int i = 0; i < d->row_count; i++) {
+    gpio_set_intr_type(d->rows[i], GPIO_INTR_DISABLE);
+  }
+}
+
+// Just takes the channel number. Cleans up the resources used.
+static int matrix_close(DATA *d) {
+  if (!d) {
+    return 0;
+  }
+
+  disable_row_interrupts(d);
+
+  for (int i = 0; i < d->row_count; i++) {
+    gpio_isr_handler_remove(d->rows[i]);
+  }
+
+  for (int i = 0; i < d->column_count; i++) {
+    set_gpio_mode_input(d->columns[i], GPIO_INTR_DISABLE);
+  }
+
+  return 0;
+}
+
+// Character returned is 0 .. max if pressed. -1 if not.
+static int matrix_get_character(DATA *d)
+{
+  set_columns(d, 1);
+  disable_row_interrupts(d);
+
+  int character = -1;
+
+  // We are either waiting for a negative edge (keypress) or a positive edge
+  // (keyrelease)
+
+  for (int i = 0; i < d->column_count && character < 0; i++) {
+    gpio_set_level(d->columns[i], 0);
+
+    for (int j = 0; j < d->row_count && character < 0; j++) {
+      if (gpio_get_level(d->rows[j]) == 0) {
+        // We found a keypress
+        character = j * d->column_count + i;
+      }
+    }
+
+    gpio_set_level(d->columns[i], 1);
+  }
+
+  return character;
+}
+
+static void matrix_queue_character(DATA *d, int character)
+{
+  // If character is >= 0 then we have found the character -- so send it.
+
+  if ((d->state == WAITING_FOR_PRESS && character >= 0) || (d->state == WAITING_FOR_RELEASE && character < 0)) {
+    if (character >= 0) {
+      character++;
+      d->last_character = character;
+    } else {
+      character = -d->last_character;
+    }
+
+    if (HAS_QUEUE_SPACE(d)) {
+      QUEUE_IT(d, character);
+      if (!d->task_queued) {
+        if (task_post_medium(tasknumber, (task_param_t)d)) {
+          d->task_queued = 1;
+        }
+      }
+    }
+  }
+}
+
+static void matrix_interrupt(void *arg) {
+  // This function runs with high priority
+  DATA *d = (DATA *)arg;
+
+  int character = matrix_get_character(d);
+
+  matrix_queue_character(d, character);
+
+  d->state = character >= 0 ? WAITING_FOR_RELEASE : WAITING_FOR_PRESS;
+  esp_timer_start_once(d->timer_handle, 5000);
+}
+
+static bool matrix_has_queued_event(DATA *d) {
+  if (!d) {
+    return false;
+  }
+
+  return HAS_QUEUED_DATA(d);
+}
+
+// Get the oldest event in the queue and remove it (if possible)
+static bool matrix_getevent(DATA *d, matrix_event_t *resultp) {
+  matrix_event_t result = {0};
+
+  if (!d) {
+    return false;
+  }
+
+  bool status = false;
+
+  if (HAS_QUEUED_DATA(d)) {
+    result = GET_READ_STATUS(d);
+    d->read_offset++;
+    status = true;
+  } else {
+    result = GET_LAST_STATUS(d);
+  }
+
+  *resultp = result;
+
+  return status;
+}
+
+static void callback_free_one(lua_State *L, int *cb_ptr)
+{
+  if (*cb_ptr != LUA_NOREF) {
+    luaL_unref(L, LUA_REGISTRYINDEX, *cb_ptr);
+    *cb_ptr = LUA_NOREF;
+  }
+}
+
+static void callback_free(lua_State* L, DATA *d, int mask)
+{
+  if (d) {
+    int i;
+    for (i = 0; i < CALLBACK_COUNT; i++) {
+      if (mask & (1 << i)) {
+        callback_free_one(L, &d->callback[i]);
+      }
+    }
+  }
+}
+
+static int callback_setOne(lua_State* L, int *cb_ptr, int arg_number)
+{
+  if (lua_isfunction(L, arg_number)) {
+    lua_pushvalue(L, arg_number);  // copy argument (func) to the top of stack
+    callback_free_one(L, cb_ptr);
+    *cb_ptr = luaL_ref(L, LUA_REGISTRYINDEX);
+    return 0;
+  }
+
+  return -1;
+}
+
+static int callback_set(lua_State* L, DATA *d, int mask, int arg_number)
+{
+  int result = 0;
+
+  int i;
+  for (i = 0; i < CALLBACK_COUNT; i++) {
+    if (mask & (1 << i)) {
+      result |= callback_setOne(L, &d->callback[i], arg_number);
+    }
+  }
+
+  return result;
+}
+
+static void callback_callOne(lua_State* L, int cb, int mask, int arg, uint32_t time)
+{
+  if (cb != LUA_NOREF) {
+    lua_rawgeti(L, LUA_REGISTRYINDEX, cb);
+
+    lua_pushinteger(L, mask);
+    lua_pushvalue(L, arg - 2);
+    lua_pushinteger(L, time);
+
+    luaL_pcallx(L, 3, 0);
+  }
+}
+
+static void callback_call(lua_State* L, DATA *d, int cbnum, int key, uint32_t time)
+{
+  if (d) {
+    lua_rawgeti(L, LUA_REGISTRYINDEX, d->character_ref);
+    lua_rawgeti(L, -1, key);
+    if (lua_type(L, -1) != LUA_TNIL) {
+      callback_callOne(L, d->callback[cbnum], 1 << cbnum, -1, time);
+    }
+    lua_pop(L, 2);
+  }
+}
+
+static void getpins(lua_State *L, int argno, int count, uint8_t *dest)
+{
+  for (int i = 1; i <= count; i++) {
+    lua_rawgeti(L, argno, i);
+    *dest++ = lua_tonumber(L, -1);
+    lua_pop(L, 1);
+  }
+}
+
+// Lua: setup({cols}, {rows}, {characters})
+static int lmatrix_setup( lua_State* L )
+{
+  luaL_checktype(L, 1, LUA_TTABLE);
+  luaL_checktype(L, 2, LUA_TTABLE);
+  luaL_checktype(L, 3, LUA_TTABLE);
+
+  // Get the sizes of the first two tables
+  size_t columns = lua_rawlen(L, 1);
+  size_t rows = lua_rawlen(L, 2);
+
+  if (columns > 255 || rows > 255 || !rows || !columns) {
+    return luaL_error(L, "Number of rows or columns out of range");
+  }
+
+  DATA *d = (DATA *)lua_newuserdata(L, sizeof(DATA) + rows + columns);
+  if (!d) return luaL_error(L, "not enough memory");
+  memset(d, 0, sizeof(*d) + rows + columns);
+  luaL_getmetatable(L, "matrix.keyboard");
+  lua_setmetatable(L, -2);
+
+  // create a self_ref to prevent GC
+
+  lua_pushvalue(L, -1);
+  d->self_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+  d->columns = (uint8_t *) (d + 1);
+  d->rows = d->columns + columns;
+  d->column_count = columns;
+  d->row_count = rows;
+
+  esp_timer_create_args_t timer_args = {
+    .callback = lmatrix_timer_done,
+    .dispatch_method = ESP_TIMER_TASK,
+    .name = "matrix_timer",
+    .arg = d
+  };
+
+  d->open = true;
+
+  esp_timer_create(&timer_args, &d->timer_handle);
+
+  for (int i = 0; i < CALLBACK_COUNT; i++) {
+    d->callback[i] = LUA_NOREF;
+  }
+  getpins(L, 1, columns, d->columns);
+  getpins(L, 2, rows, d->rows);
+  lua_pushvalue(L, 3);
+  d->character_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+  for (int i = 0; i < d->row_count; i++) {
+    gpio_isr_handler_add(d->rows[i], matrix_interrupt, d);
+  }
+  initialize_pins(L, d);
+
+  return 1;
+}
+
+// Lua: close( )
+static int lmatrix_close( lua_State* L )
+{
+  DATA *d = (DATA *)luaL_checkudata(L, 1, "matrix.keyboard");
+
+  if (d->open) {
+    callback_free(L, d, MATRIX_ALL);
+
+    if (matrix_close( d )) {
+      return luaL_error( L, "Unable to close switch." );
+    }
+
+    esp_timer_stop(d->timer_handle);
+    esp_timer_delete(d->timer_handle);
+    luaL_unref(L, LUA_REGISTRYINDEX, d->character_ref);
+
+    if (!HAS_QUEUED_DATA(d)) {
+      luaL_unref(L, LUA_REGISTRYINDEX, d->self_ref);
+    }
+
+    d->open = false;
+  }
+  return 0;
+}
+
+// Lua: on( mask[, cb] )
+static int lmatrix_on( lua_State* L )
+{
+  DATA *d = (DATA *)luaL_checkudata(L, 1, "matrix.keyboard");
+
+  int mask = luaL_checkinteger(L, 2);
+
+  if (lua_gettop(L) >= 3) {
+    if (callback_set(L, d, mask, 3)) {
+      return luaL_error( L, "Unable to set callback." );
+    }
+  } else {
+    callback_free(L, d, mask);
+  }
+
+  return 0;
+}
+
+// Returns TRUE if there maybe/is more stuff to do
+static bool lmatrix_dequeue_single(lua_State* L, DATA *d)
+{
+  bool something_pending = false;
+
+  if (d) {
+    matrix_event_t result;
+
+    if (matrix_getevent(d, &result)) {
+      int character = result.character;
+
+      callback_call(L, d, character > 0 ? MATRIX_PRESS_INDEX : MATRIX_RELEASE_INDEX, character < 0 ? -character : character, result.time_us);
+
+      d->task_queued = 0;
+      something_pending = matrix_has_queued_event(d);
+    }
+  }
+
+  return something_pending;
+}
+
+static void lmatrix_timer_done(void *param)
+{
+  DATA *d = (DATA *) param;
+
+  // We need to see if the key is still pressed, and if so, enable rising edge interrupts
+
+  int character = matrix_get_character(d);
+
+  matrix_queue_character(d, character);
+
+  if (d->state == WAITING_FOR_RELEASE && character < 0) {
+    d->state = WAITING_FOR_DEBOUNCE;
+  } else if (character >= 0) {
+    d->state = WAITING_FOR_RELEASE;
+  } else {
+    d->state = WAITING_FOR_PRESS;
+  }
+
+  if (d->state == WAITING_FOR_PRESS) {
+    for (int i = 0; i < d->row_count; i++) {
+      gpio_set_intr_type(d->rows[i], GPIO_INTR_NEGEDGE);
+    }
+    set_columns(d, 0);
+  } else {
+    esp_timer_start_once(d->timer_handle, 40000);
+  }
+}
+
+static void lmatrix_task(task_param_t param, task_prio_t prio)
+{
+  (void) prio;
+
+  bool need_to_post = false;
+  lua_State *L = lua_getstate();
+
+  DATA *d = (DATA *) param;
+  if (d) {
+    if (lmatrix_dequeue_single(L, d)) {
+      need_to_post = true;
+    }
+  }
+
+  if (need_to_post) {
+    // If there is pending stuff, queue another task
+    task_post_medium(tasknumber, param);
+  } else if (d) {
+    if (!d->open) {
+      luaL_unref(L, LUA_REGISTRYINDEX, d->self_ref);  
+    }
+  }
+}
+
+
+// Module function map
+LROT_BEGIN(matrix, NULL, 0)
+  LROT_FUNCENTRY( setup, lmatrix_setup )
+  LROT_NUMENTRY( PRESS, MASK(PRESS) )
+  LROT_NUMENTRY( RELEASE, MASK(RELEASE) )
+  LROT_NUMENTRY( ALL, MATRIX_ALL )
+LROT_END(matrix, NULL, 0)
+
+// Module function map
+LROT_BEGIN(matrix_keyboard, NULL, LROT_MASK_GC_INDEX)
+  LROT_FUNCENTRY(__gc, lmatrix_close)
+  LROT_TABENTRY(__index, matrix_keyboard)
+  LROT_FUNCENTRY(on, lmatrix_on)
+  LROT_FUNCENTRY(close, lmatrix_close)
+LROT_END(matrix_keyboard, NULL, LROT_MASK_GC_INDEX)
+
+static int matrix_open(lua_State *L) {
+  luaL_rometatable(L, "matrix.keyboard",
+                    LROT_TABLEREF(matrix_keyboard));  // create metatable
+  tasknumber = task_get_id(lmatrix_task);
+  return 0;
+}
+
+NODEMCU_MODULE(MATRIX, "matrix", matrix, matrix_open);
diff --git a/docs/modules/matrix.md b/docs/modules/matrix.md
new file mode 100644
index 00000000..edf803a1
--- /dev/null
+++ b/docs/modules/matrix.md
@@ -0,0 +1,77 @@
+# matrix Module
+| Since  | Origin / Contributor  | Maintainer  | Source  |
+| :----- | :-------------------- | :---------- | :------ |
+| 2024-02-01 | [Philip Gladstone](https://github.com/pjsg) | [Philip Gladstone](https://github.com/pjsg) | [matrix.c](../../components/modules/matrix.c)|
+
+
+This module processes key presses on matrixed keyboards such as cheap numeric keypads with the # and * keys. These are organized as a 3x4 matrix with 7 connections
+in all.
+
+## Sources for parts
+
+- Adafruit: [Matrix keypad](https://www.adafruit.com/search?q=matrix+keypad)
+- Aliexpress: This [search](https://www.aliexpress.us/w/wholesale-matrix-keypad.html) reveals all sorts of shapes and sizes.
+
+## Constants
+- `matrix.PRESS = 1` The eventtype for a keyboard key press
+- `matrix.RELEASE = 2` The eventtype for keyboard key release.
+- `matrix.ALL = 3` Covers all event types
+
+## matrix.setup()
+Initialize the nodemcu to talk to a matrixed keyboard.
+
+#### Syntax
+`keyboard = matrix.setup({column pins}, {row pins}, {key characters})`
+
+#### Parameters
+- `column pins` These are the GPIO numbers of the pins connected to the columns of the keyboard
+- `row pins` These are the GPIO numbers of the pins connected to the rows of the keyboard
+- `key characters` These are the characters (or strings) to be returned when a key is pressed. The first character corresponds to the first row and first column. The next character is the second column and first row, etc.
+
+#### Returns
+The keyboard object. 
+
+
+#### Example
+
+    keyboard = matrix.setup({17, 4, 18}, {16, 21, 19, 5}, { "1", "2", "3", "4", "5", "6", "7", "8", "9", "*", "0", "#"})
+
+#### Notes
+If an entry in the key characters table is nil, then that key press will not be reported.
+
+## keyboard:on()
+Sets a callback on specific events.
+
+#### Syntax
+`keyboard:on(eventtype[, callback])`
+
+#### Parameters
+- `eventtype` This defines the type of event being registered. This can be one or more of `matrix.PRESS` and `matrix.RELEASE`. `matrix.ALL` covers all the event types.
+- `callback` This is a function that will be invoked when the specified event happens.
+
+If the callback is None or omitted, then the registration is cancelled.
+
+The callback will be invoked with three arguments when the event happens. The first argument is the eventtype,
+the second is the character, and the third is the time when the event happened.
+
+The time is the number of microseconds represented in a 32-bit integer. Note that this wraps every hour or so.
+
+#### Example
+
+    keyboard:on(matrix.ALL, function (type, char, when)
+      print("Character=" .. char .. " event type=" .. type .. " time=" .. when)
+    end)
+
+#### Errors
+If an invalid `eventtype` is supplied, then an error will be thrown.
+
+## keyboard:close()
+Releases the resources associated with the matrix keyboard.
+
+#### Syntax
+`keyboard:close()`
+
+#### Example
+
+    keyboard:close()
+