How to convert an image file to base64 string using Arduino UNO or using any other Microcontroller? - image-processing

Question

Suppose I am in a room which is totally locked and I am begging for the key, so I can go outside. But the person who locked the door behind me is asking to solve a problem for him. The problem is that I have an SD card, SD card module, Arduino UNO, power, a laptop with internet access. What I need to do for the person is that I have to convert an image file stored in the SD card to a base64 string using the Arduino. Now I want to know how to this task for the person, so I can go out freely. Kindly remember the title of this question, otherwise, my life is in danger, and please avoid suggestions only. If you have done this before, then you might answer the question, otherwise please do not. Sorry for being harsh, but it is really bad to have a bad answer. StackOverflow is my last hope.
I have used a library called base64 for Arduino, but I didn't solve my problem. Here is the library. https://github.com/adamvr/arduino-base64

Answer 1

My aim was to convert image to the Base64 string format and then send this string through ESP8266 module to the webserver.
Until now, I didn't find any solution to this problem. I found an alternative to send images taken by a camera. That alternative is a camera module with ESP32-S. This module is "ESP32-S Cam", which takes pictures and sends them to an online webserver.
Here is the code for ESP32 Cam for taking and sending picture to the server where we will have a PHP Scrip given under this code.
#include "esp_http_client.h"
#include "esp_camera.h"
#include <WiFi.h>
#include "Arduino.h"
const char* ssid = "ashiq"; // my wifi "SSID" name
const char* password = "11585858"; // my wifi Password
int capture_interval = 20000; // Microseconds between captures
const char *post_url = "http://app.softwarism.com/esp32/getPhoto.php"; // Location where images are POSTED
bool internet_connected = false;
long current_millis;
long last_capture_millis = 0;
//for indicating that the picture has been taken and then sent
#define GPIO_PIN_WAKEUP GPIO_NUM_12
// CAMERA_MODEL_AI_THINKER
#define PWDN_GPIO_NUM 32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 0
#define SIOD_GPIO_NUM 26
#define SIOC_GPIO_NUM 27
#define Y9_GPIO_NUM 35
#define Y8_GPIO_NUM 34
#define Y7_GPIO_NUM 39
#define Y6_GPIO_NUM 36
#define Y5_GPIO_NUM 21
#define Y4_GPIO_NUM 19
#define Y3_GPIO_NUM 18
#define Y2_GPIO_NUM 5
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22
void setup()
{
Serial.begin(115200);
//Setup indication pin Mode
pinMode(GPIO_PIN_WAKEUP,OUTPUT);
if (init_wifi()) { // Connected to WiFi
internet_connected = true;
Serial.println("Internet connected");
}
camera_config_t config;
config.ledc_channel = LEDC_CHANNEL_0;
config.ledc_timer = LEDC_TIMER_0;
config.pin_d0 = Y2_GPIO_NUM;
config.pin_d1 = Y3_GPIO_NUM;
config.pin_d2 = Y4_GPIO_NUM;
config.pin_d3 = Y5_GPIO_NUM;
config.pin_d4 = Y6_GPIO_NUM;
config.pin_d5 = Y7_GPIO_NUM;
config.pin_d6 = Y8_GPIO_NUM;
config.pin_d7 = Y9_GPIO_NUM;
config.pin_xclk = XCLK_GPIO_NUM;
config.pin_pclk = PCLK_GPIO_NUM;
config.pin_vsync = VSYNC_GPIO_NUM;
config.pin_href = HREF_GPIO_NUM;
config.pin_sscb_sda = SIOD_GPIO_NUM;
config.pin_sscb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.pixel_format = PIXFORMAT_JPEG;
//init with high specs to pre-allocate larger buffers
if (psramFound()) {
config.frame_size = FRAMESIZE_UXGA;
config.jpeg_quality = 10;
config.fb_count = 2;
} else {
config.frame_size = FRAMESIZE_SVGA;
config.jpeg_quality = 12;
config.fb_count = 1;
}
// camera init
esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK) {
Serial.printf("Camera init failed with error 0x%x", err);
return;
}
}
bool init_wifi()
{
int connAttempts = 0;
Serial.println("\r\nConnecting to: " + String(ssid));
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED ) {
delay(500);
Serial.print(".");
if (connAttempts > 10) return false;
connAttempts++;
}
return true;
}
esp_err_t _http_event_handler(esp_http_client_event_t *evt)
{
switch (evt->event_id) {
case HTTP_EVENT_ERROR:
Serial.println("HTTP_EVENT_ERROR");
break;
case HTTP_EVENT_ON_CONNECTED:
Serial.println("HTTP_EVENT_ON_CONNECTED");
break;
case HTTP_EVENT_HEADER_SENT:
Serial.println("HTTP_EVENT_HEADER_SENT");
break;
case HTTP_EVENT_ON_HEADER:
Serial.println();
Serial.printf("HTTP_EVENT_ON_HEADER, key=%s, value=%s", evt->header_key, evt->header_value);
break;
case HTTP_EVENT_ON_DATA:
Serial.println();
Serial.printf("HTTP_EVENT_ON_DATA, len=%d", evt->data_len);
if (!esp_http_client_is_chunked_response(evt->client)) {
// Write out data
// printf("%.*s", evt->data_len, (char*)evt->data);
}
break;
case HTTP_EVENT_ON_FINISH:
Serial.println("");
Serial.println("HTTP_EVENT_ON_FINISH");
break;
case HTTP_EVENT_DISCONNECTED:
Serial.println("HTTP_EVENT_DISCONNECTED");
break;
}
return ESP_OK;
}
static esp_err_t take_send_photo()
{
Serial.println("Taking picture...");
camera_fb_t * fb = NULL;
esp_err_t res = ESP_OK;
fb = esp_camera_fb_get();
if (!fb) {
Serial.println("Camera capture failed");
return ESP_FAIL;
}else{
indication();
}
esp_http_client_handle_t http_client;
esp_http_client_config_t config_client = {0};
config_client.url = post_url;
config_client.event_handler = _http_event_handler;
config_client.method = HTTP_METHOD_POST;
http_client = esp_http_client_init(&config_client);
esp_http_client_set_post_field(http_client, (const char *)fb->buf, fb->len);
esp_http_client_set_header(http_client, "Content-Type", "image/jpg");
esp_err_t err = esp_http_client_perform(http_client);
if (err == ESP_OK) {
Serial.print("esp_http_client_get_status_code: ");
Serial.println(esp_http_client_get_status_code(http_client));
}
esp_http_client_cleanup(http_client);
esp_camera_fb_return(fb);
}
void loop()
{
// TODO check Wifi and reconnect if needed
current_millis = millis();
if (current_millis - last_capture_millis > capture_interval) { // Take another picture
last_capture_millis = millis();
take_send_photo();
//indicate that the picture has been taken and sent
indication();
}
}
void indication(){
digitalWrite(GPIO_PIN_WAKEUP,HIGH);
delay(1000);
digitalWrite(GPIO_PIN_WAKEUP,LOW);
}
Here is the PHP Script waiting to get the picture sent by the camera.
<?php
require_once("con.php");
$received = file_get_contents('php://input');
$fileToWrite = "uploads/smart_tick_".time().".jpg";
if(file_put_contents($fileToWrite, $received)){
echo "Uploaded";
}
?>
Note: Do not forget to create a folder "uploads" in the same directory where the PHP Script is.