I've been trying to learn ESP32 for class with the first edition of Vedat Oner's textbook (course requirement) and it's starting to seem like every other dependency has been broken by new versions since it was published. Using VSCode with PlatformIO in the ESP-IDF architecture. Dev board is Freenove ESP32-WROVER.
I copied the following example code from the textbook verbatim, except I changed DHT11_PIN from 17 to 34 because my dev board doesn't have pin 17 available (author was using a different model).
#include <stdio.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include "dht.h"
#include "driver/gpio.h"
// defines
#define DHT11_PIN 34
#define BUZZER_PIN 18
#define BUZZER_PIN_SEL (1ULL << BUZZER_PIN)
#define HUM_THRESHOLD 800
#define TEMP_THRESHOLD 250
// globals
static int16_t temperature;
static bool temp_alarm = false;
static int16_t humidity;
static bool hum_alarm =false;
// initialize hardware
static void init_hw(void) {
gpio_config_t io_conf;
io_conf.mode = GPIO_MODE_OUTPUT;
io_conf.pin_bit_mask = BUZZER_PIN_SEL;
io_conf.intr_type = GPIO_INTR_DISABLE;
io_conf.pull_down_en = 0;
io_conf.pull_up_en = 0;
gpio_config(&io_conf);
}
// generates alarm beep
static void beep(void *arg) {
int cnt = 2 * (int)arg;
bool state = true;
for (int i = 0; i < cnt; ++i, state = !state) {
gpio_set_level(BUZZER_PIN, state);
vTaskDelay(100 / portTICK_PERIOD_MS);
}
vTaskDelete(NULL);
}
// checks for humidity and temp alarms
static void check_alarm(void) {
bool is_alarm = temperature >= TEMP_THRESHOLD;
bool run_beep = is_alarm && !temp_alarm;
temp_alarm = is_alarm;
if (run_beep) {
xTaskCreate(beep, "beep", configMINIMAL_STACK_SIZE, (void *)3, 5, NULL);
return;
}
is_alarm = humidity >= HUM_THRESHOLD;
run_beep = is_alarm && !hum_alarm;
hum_alarm = is_alarm;
if (run_beep) {
xTaskCreate(beep, "beep", configMINIMAL_STACK_SIZE, (void *)2, 5, NULL);
}
}
void app_main() {
init_hw();
while (1) {
if (dht_read_data(DHT_TYPE_DHT11, (gpio_num_t)DHT11_PIN, &humidity, &temperature) == ESP_OK) {
printf("Humidity: %d%% Temp: %dC\n", humidity / 10, temperature / 10); check_alarm();
}
else {
printf("Could not read data from sensor\n");
}
vTaskDelay(2000 / portTICK_PERIOD_MS);
}
}
The DHT11 example uses dht.c, but the function ets_delay_us() at lines 94 and 119 seems to have been removed in an update at some point. I tried the suggested fix of replacing it with esp_rom_delay_us() and it compiled, but when I uploaded it to the ESP32 and monitored, it flipped out: the console started spitting out an endless stream of gibberish like this:
ELF file SHA256: 840611cd9
Rebooting...
ets Jul 29 2019 12:21:46
rst:0xc (SW_CPU_RESET),boot:0x1b (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0030,len:7176
load:0x40078000,len:15564
ho 0 tail 12 room 4
load:0x40080400,len:4
load:0x40080404,len:3904
entry 0x40080638
␛[0;32mI (31) boot: ESP-IDF 5.3.1 2nd stage bootloader␛[0m
␛[0;32mI (31) boot: compile time Nov 5 2024 22:19:16␛[0m
␛[0;32mI (31) boot: Multicore bootloader␛[0m
␛[0;32mI (35) boot: chip revision: v3.1␛[0m
␛[0;32mI (39) boot.esp32: SPI Speed : 40MHz␛[0m
␛[0;32mI (44) boot.esp32: SPI Mode : DIO␛[0m
␛[0;32mI (48) boot.esp32: SPI Flash Size : 4MB␛[0m
␛[0;32mI (53) boot: Enabling RNG early entropy source...␛[0m
␛[0;32mI (58) boot: Partition Table:␛[0m
␛[0;32mI (62) boot: ## Label Usage Type ST Offset Length␛[0m
␛[0;32mI (69) boot: 0 nvs WiFi data 01 02 00009000 00006000␛[0m
␛[0;32mI (76) boot: 1 phy_init RF data 01 01 0000f000 00001000␛[0m
␛[0;32mI (84) boot: 2 factory factory app 00 00 00010000 00100000␛[0m
␛[0;32mI (91) boot: End of partition table␛[0m
␛[0;32mI (96) esp_image: segment 0: paddr=00010020 vaddr=3f400020 size=09d4ch ( 40268) map␛[0m
␛[0;32mI (118) esp_image: segment 1: paddr=00019d74 vaddr=3ffb0000 size=02368h ( 9064) load␛[0m
␛[0;32mI (122) esp_image: segment 2: paddr=0001c0e4 vaddr=40080000 size=03f34h ( 16180) load␛[0m
␛[0;32mI (130) esp_image: segment 3: paddr=00020020 vaddr=400d0020 size=14cb8h ( 85176) map␛[0m
␛[0;32mI (161) esp_image: segment 4: paddr=00034ce0 vaddr=40083f34 size=08af0h ( 35568) load␛[0m
␛[0;32mI (182) boot: Loaded app from partition at offset 0x10000␛[0m
␛[0;32mI (182) boot: Disabling RNG early entropy source...␛[0m
␛[0;32mI (194) cpu_start: Multicore app␛[0m
␛[0;32mI (202) cpu_start: Pro cpu start user code␛[0m
␛[0;32mI (202) cpu_start: cpu freq: 160000000 Hz␛[0m
␛[0;32mI (202) app_init: Application information:␛[0m
␛[0;32mI (205) app_init: Project name: DHT11_demo␛[0m
␛[0;32mI (210) app_init: App version: 1␛[0m
␛[0;32mI (215) app_init: Compile time: Nov 5 2024 22:17:47␛[0m
␛[0;32mI (221) app_init: ELF file SHA256: 840611cd9...␛[0m
␛[0;32mI (226) app_init: ESP-IDF: 5.3.1␛[0m
␛[0;32mI (231) efuse_init: Min chip rev: v0.0␛[0m
␛[0;32mI (236) efuse_init: Max chip rev: v3.99 ␛[0m
␛[0;32mI (240) efuse_init: Chip rev: v3.1␛[0m
␛[0;32mI (246) heap_init: Initializing. RAM available for dynamic allocation:␛[0m
␛[0;32mI (253) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM␛[0m
␛[0;32mI (259) heap_init: At 3FFB2C30 len 0002D3D0 (180 KiB): DRAM␛[0m
␛[0;32mI (265) heap_init: At 3FFE0440 len 00003AE0 (14 KiB): D/IRAM␛[0m
␛[0;32mI (271) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM␛[0m
␛[0;32mI (278) heap_init: At 4008CA24 len 000135DC (77 KiB): IRAM␛[0m
␛[0;32mI (285) spi_flash: detected chip: generic␛[0m
␛[0;32mI (288) spi_flash: flash io: dio␛[0m
␛[0;32mI (293) main_task: Started on CPU0␛[0m
␛[0;32mI (303) main_task: Calling app_main()␛[0m
␛[0;32mI (303) gpio: GPIO[18]| InputEn: 0| OutputEn: 1| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0 ␛[0m
␛[0;31mE (303) gpio: io_num=34 can only be input␛[0m
␛[0;31mE (313) gpio: gpio_set_level(239): GPIO output gpio_num error␛[0m
abort() was called at PC 0x40082867 on core 0
Backtrace: 0x40082122:0x3ffb3970 0x4008559d:0x3ffb3990 0x4008b2fd:0x3ffb39b0 0x40082867:0x3ffb3a20 0x400829a5:0x3ffb3a50 0x40082a1e:0x3ffb3a70 0x400d8f2e:0x3ffb3aa0 0x400d8561:0x3ffb3dc0 0x400e4c51:0x3ffb3df0 0x4008b1b1:0x3ffb3e20 0x400d1ece:0x3ffb3e70 0x400d0fc9:0x3ffb3ea0 0x400d1171:0x3ffb3ed0 0x400d0f38:0x3ffb3f00 0x400e4470:0x3ffb3f20 0x40085e01:0x3ffb3f50
I have no idea what any of this means, and I tried using a hair dryer to raise the temperature of the sensor above threshold and the buzzer didn't go off.
The messages are not gibberish. They contain valuable information about the boot process and why your program crashed. Among them you shared there's a line that explains the problem:
␛[0;31mE (303) gpio: io_num=34 can only be input␛[0m
Some GPIO pins have restrictions on them. GPIO34, 35, 36 and 39 are all input only. You chose GPIO34. The library you're using needs to do both input and output on that, which causes the failure you're seeing.
Pick a different pin, one that's not a strapping pin (which determines how the CPU boots, GPIO0 and GPIO12 on this CPU) and one that's not input only.
Here's a useful guide to which pins are available for what uses. The CPU model (in this case, vanilla ESP32) matters, the specific board does not.