Initial commit

examples/dht22_temp_hum/CMakeLists.txt

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+# Copyright 2017 Rafal Zajac <rzajac@gmail.com>.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+
+find_package(esp_sdo REQUIRED)
+find_package(esp_util REQUIRED)
+
+add_executable(dht22_temp_hum main.c ${ESP_USER_CONFIG})
+
+target_include_directories(dht22_temp_hum PUBLIC
+    ${ESP_USER_CONFIG_DIR}
+    ${esp_sdo_INCLUDE_DIRS}
+    ${esp_util_INCLUDE_DIRS})
+
+target_link_libraries(dht22_temp_hum
+    ${esp_sdo_LIBRARIES}
+    ${esp_util_LIBRARIES}
+    esp_dht22)
+
+esp_gen_exec_targets(dht22_temp_hum)

examples/dht22_temp_hum/README.md

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+## DHT22 example.
+
+Demonstrates how to get temperature and humidity from DHT22 sensor.
+
+## Flashing
+
+```
+$ cd build
+$ cmake ..
+$ make dht22_temp_hum_flash
+$ miniterm.py /dev/ttyUSB0 74880
+```

examples/dht22_temp_hum/main.c

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+/*
+ * Copyright 2017 Rafal Zajac <rzajac@gmail.com>.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <user_interface.h>
+#include <esp_gpio.h>
+#include <esp_dht22.h>
+#include <mem.h>
+#include <esp_sdo.h>
+
+os_timer_t timer;
+
+/**
+ * Rise base to power of.
+ *
+ * From: http://bbs.espressif.com/viewtopic.php?t=246
+ *
+ * @param base The number.
+ * @param exp  The exponent.
+ *
+ * @return Product.
+ */
+static int ICACHE_FLASH_ATTR
+power(int base, int exp)
+{
+  int result = 1;
+  while (exp) {
+    result *= base;
+    exp--;
+  }
+
+  return result;
+}
+
+/**
+ * Get string representation of float.
+ *
+ * From: http://bbs.espressif.com/viewtopic.php?t=246
+ *
+ * Warning: limited to 15 chars & non-reentrant.
+ *          e.g., don't use more than once per os_printf call.
+ *
+ * @param num       The float to convert to string.
+ * @param decimals  The number of decimal places.
+ *
+ * @return The float string representation.
+ */
+static char *ICACHE_FLASH_ATTR
+ftoa(float num, uint8_t decimals)
+{
+  static char *buf[16];
+
+  int whole = (int) num;
+  int decimal = (int) ((num - whole) * power(10, decimals));
+  if (decimal < 0) {
+    // get rid of sign on decimal portion
+    decimal -= 2 * decimal;
+  }
+
+  char *pattern[10]; // setup printf pattern for decimal portion
+  os_sprintf((char *) pattern, "%%d.%%0%dd", decimals);
+  os_sprintf((char *) buf, (const char *) pattern, whole, decimal);
+
+  return (char *) buf;
+}
+
+void ICACHE_FLASH_ATTR
+sys_init_done(void* arg)
+{
+  esp_dht22_err err;
+  esp_dht22_dev *dev = esp_dht22_new_dev(GPIO2);
+
+  // Get temperature.
+  err = esp_dht22_get(dev);
+  if (err != ESP_DHT22_OK) {
+    os_free(dev);
+    os_printf("DHT22 error code: %d\n", err);
+    return;
+  }
+
+  os_printf("Temp: %s\n", ftoa(dev->temp, 2));
+  os_printf("Hum: %s\n", ftoa(dev->hum, 2));
+  os_printf("--------------------\n");
+  os_free(dev);
+}
+
+void ICACHE_FLASH_ATTR
+user_init()
+{
+  // No need for wifi for this example.
+  wifi_station_disconnect();
+  wifi_set_opmode_current(NULL_MODE);
+
+  //system_init_done_cb(sys_init_done);
+  stdout_init(BIT_RATE_74880);
+
+  // Initialize DHT22 on GPIO 2.
+  esp_dht22_init(GPIO2);
+
+  // Wait before running main code.
+  os_printf("Initialized.\n");
+  os_timer_disarm(&timer);
+  os_timer_setfn(&timer, sys_init_done, NULL);
+  os_timer_arm(&timer, 1500, true);
+}