diff --git a/README.md b/README.md
index 5e11b9e..85af64e 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,13 @@
 JSON Logger
 ======
-An easy-to-use, small, fast, and portable JSON builder and logger for IoT firmware data gathering.
+An easy-to-use, small, fast and portable JSON builder and logger for IoT logging, data acquisition and analytics.
 
 ### Usage:
 
 Special prefixes to indicate data types: 
 ```javascript
-s| i| d|# b| o| 
-s[ i[ d[# b[ o[
+s| i| f|# b| o| 
+s[ i[ f[# b[ o[
 -{ +| 
 ``` 
 
@@ -22,11 +22,11 @@ s[ i[ d[# b[ o[
   // s|key: value is a string (can be used to escape prefix: 
   //        e.g. "s|i|..." if you want your key to start with i|)
   // i|key: value is an integer (32 bits)
-  // d|#key: value is a floating number with 1 to 17 significant 
+  // f|#key: value is a floating number with 1 to 17 significant 
   //         digits (a is 10, b is 11 ... h is 17).
   // b|key: value is a boolean
   // o|key: value is anything else (object, array, null)
-  json(buf256, "str_key1", "str1", "i|int_key1", 7, "d|3double_key1", 3.14159,
+  json(buf256, "str_key1", "str1", "i|int_key1", 7, "f|3double_key1", 3.14159,
     "b|boolean_key1", 1, "o|object_key1", "{}", "o|array_key1", "[]", "o|null_key1", "null");
   // => {"str_key1":"str1","int_key1":7,"double_key1":3.14,"boolean_key1":true,
   //     "object_key1":{},"array_key1":[],"null_key1":null}
@@ -53,13 +53,13 @@ s[ i[ d[# b[ o[
   json(buf64, "i[", 3, 0, -2147483648, 2147483647);
   // => [0,-2147483648,2147483647]
 
-  // "d[#": a floating number array with 1 to 17 significant 
+  // "f[#": a floating number array with 1 to 17 significant 
   //        digits (a is 10, b is 11 ... h is 17)
-  json(buf64, "d[1", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
+  json(buf64, "f[1", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
   // => [0,0.01,4,1]
-  json(buf64, "d[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
+  json(buf64, "f[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
   // => [0,0.01,4.44,1.234568]
-  json(buf64, "d[h", 4, 0.0, 0.01, 4.44, -1.2345678901234567890);
+  json(buf64, "f[h", 4, 0.0, 0.01, 4.44, -1.2345678901234567890);
   // => [0,0.01,4.4400000000000004,-1.2345678901234567]
 
   // "b[": a boolean array
@@ -76,7 +76,7 @@ s[ i[ d[# b[ o[
 #include <JsonLogger.h>
 
 void to_console(int level, const char* json) {
-  char mod[LOG_MAX_LEN];
+  char mof[LOG_MAX_LEN];
   strcpy(mod, json);
 
   logModifyForHuman(level, mod);
@@ -96,7 +96,7 @@ void to_mqtt(int level, const char* json) {
 
   logTrace("should not be logged at all if LOG_MIN_LEVEL is not changed to 0");
   logDebug("Debug");
-  logInfo("i|status", -1, "d|5pi", 3.14159, "Info");
+  logInfo("i|status", -1, "f|5pi", 3.14159, "Info");
   logWarn("Warning");
   logError("Error");
   logFatal("Fatal");
diff --git a/examples/JsonBuilder/JsonBuilder.ino b/examples/JsonBuilder/JsonBuilder.ino
index d346cf2..65064ef 100644
--- a/examples/JsonBuilder/JsonBuilder.ino
+++ b/examples/JsonBuilder/JsonBuilder.ino
@@ -9,10 +9,10 @@ void setup() {
   char buf3[3], buf256[256], buf64[64], buf512[512];
   // key: value is a string
   // i|key: value is an integer
-  // d|#key: value is a floating number with 1 to 17 significant digits (a is 10, b is 11 ... h is 17).
+  // f|#key: value is a floating number with 1 to 17 significant digits (a is 10, b is 11 ... h is 17).
   // b|key: value is a boolean
   // o|key: value is anything else (object, array, null)
-  int json_len = json(buf256, "str_key1", "str1", "i|int_key1", 7, "d|3double_key1", 3.14159,
+  int json_len = json(buf256, "str_key1", "str1", "i|int_key1", 7, "f|3double_key1", 3.14159,
                       "b|boolean_key1", 1, "o|object_key1", "{}", "o|array_key1", "[]", "o|null_key1", "null");
   Serial.println(String(buf256) + " length: " + json_len);
   // {"str_key1":"str1","int_key1":7,"double_key1":3.14,"boolean_key1":true,
@@ -45,8 +45,8 @@ void setup() {
   json(buf64, "i[", 3, 0, 10, 20);
   Serial.println(buf64);  // [0,10,20]
 
-  // "d[#": a floating number array with 1 to 17 significant digits (a is 10, b is 11 ... h is 17)
-  json(buf64, "d[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
+  // "f[#": a floating number array with 1 to 17 significant digits (a is 10, b is 11 ... h is 17)
+  json(buf64, "f[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
   Serial.println(buf64);  // [0,0.01,4.44,1.234568]
 
   // "b[": a boolean array
diff --git a/examples/JsonLogger/JsonLogger.ino b/examples/JsonLogger/JsonLogger.ino
index 3d6beac..34aff4c 100644
--- a/examples/JsonLogger/JsonLogger.ino
+++ b/examples/JsonLogger/JsonLogger.ino
@@ -28,7 +28,7 @@ void setup() {
   Serial.println();
   logDebug("log to terminal, but not to file");
   Serial.println();
-  logInfo("i|status", -1, "d|5pi", 3.14159, "log to both terminal and file");
+  logInfo("i|status", -1, "f|5pi", 3.14159, "log to both terminal and file");
   Serial.println();
   logWarn("Warning");
   Serial.println();
diff --git a/library.json b/library.json
index 53fa3d3..c25f1bd 100644
--- a/library.json
+++ b/library.json
@@ -1,8 +1,8 @@
 {
   "name": "JsonLogger",
-  "version": "1.0.7",
+  "version": "1.1.0",
   "keywords": ["communication"],
-  "description": "An easy-to-use, small, fast, and portable JSON builder and logger for IoT firmware data gathering. Useful for logging json data to terminal, file, and cloud.",
+  "description": "An easy-to-use, small, fast and portable JSON builder and logger for IoT logging, data acquisition and analytics",
   "frameworks": "*",
   "platforms": "*",
   "authors": {
diff --git a/library.properties b/library.properties
index 06f7add..49ed8d7 100644
--- a/library.properties
+++ b/library.properties
@@ -1,8 +1,8 @@
 name=JsonLogger
-version=1.0.7
+version=1.1.0
 author=Alan Chen
 maintainer=Alan Chen <alanpc@gmail.com>
-sentence=An easy-to-use, small, fast, and portable JSON builder and logger for IoT firmware data gathering.
+sentence=An easy-to-use, small, fast and portable JSON builder and logger for IoT logging, data acquisition and analytics.
 paragraph=Useful for logging json data to terminal, file, and cloud
 category=Communication
 url=https://github.com/ravelab/JsonLogger
diff --git a/src/Builder.c b/src/Builder.c
index 977c2c1..fc52f24 100644
--- a/src/Builder.c
+++ b/src/Builder.c
@@ -206,7 +206,7 @@ int vbuild_json(char* json, size_t buf_size, const char* item, va_list arg) {
       case 'i':
         array = INT_ARRAY;
         break;
-      case 'd':
+      case 'f':
         array = DOUBLE_ARRAY;
         doubleArrayPrecisionChar = item[2];
         break;
@@ -256,7 +256,7 @@ int vbuild_json(char* json, size_t buf_size, const char* item, va_list arg) {
       if (item[1] == '|' && item[0] == 'i') {  // integer
         addKey(&item[2]);
         addInt();
-      } else if (item[1] == '|' && item[0] == 'd') {  // double
+      } else if (item[1] == '|' && item[0] == 'f') {  // double
         addKey(&item[3]);
         addDouble(item[2]);
       } else if (item[1] == '|' && item[0] == 'b') {  // boolean
@@ -368,7 +368,7 @@ int main() {
   int len;
   char buf3[3], buf256[256], buf64[64];
 
-  len = json(buf256, "str_key1", "str1", "i|int_key1", 7, "d|3double_key1", 3.14159,
+  len = json(buf256, "str_key1", "str1", "i|int_key1", 7, "f|3double_key1", 3.14159,
              "b|boolean_key1", 1, "o|object_key1", "{}", "o|array_key1", "[]", "o|null_key1", "null");
   printf("%s\n", buf256);
   assert(!strcmp(buf256, "{\"str_key1\":\"str1\",\"int_key1\":7,\"double_key1\":3.14,\"boolean_key1\":true,\"object_key1\":{},\"array_key1\":[],\"null_key1\":null}"));
@@ -401,18 +401,18 @@ int main() {
   assert(!strcmp(buf64, "[0,-2147483648,2147483647]"));
   assert(len == strlen(buf64));
 
-  len = json(buf64, "d[1", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
+  len = json(buf64, "f[1", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
   printf("%s\n", buf64);
   assert(!strcmp(buf64, "[0,0.01,4,1]"));
   assert(len == strlen(buf64));
 
-  // up to 17 significant number, the valid values for the * in "d[*" are 1 to h (a is 10, b is 11 ... h is 17)
-  len = json(buf64, "d[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
+  // up to 17 significant number, the valid values for the # in "f[#" are 1 to h (a is 10, b is 11 ... h is 17)
+  len = json(buf64, "f[7", 4, 0.0, 0.01, 4.44, 1.2345678901234567890);
   printf("%s\n", buf64);
   assert(!strcmp(buf64, "[0,0.01,4.44,1.234568]"));
   assert(len == strlen(buf64));
 
-  len = json(buf256, "d[h", 6, 0.0, 0.01, 4.44, -1.2345678901234567890, -0x1.fffffffffffffp+1023, -2.2250738585072014e-308);
+  len = json(buf256, "f[h", 6, 0.0, 0.01, 4.44, -1.2345678901234567890, -0x1.fffffffffffffp+1023, -2.2250738585072014e-308);
   printf("%s\n", buf256);
   assert(!strcmp(buf256, "[0,0.01,4.4400000000000004,-1.2345678901234567,-1.7976931348623157e+308,-2.2250738585072014e-308]"));
   assert(len == strlen(buf256));
@@ -497,7 +497,7 @@ int main() {
   assert(len == strlen(buf64));
 
   // compile with -O2 gets segmentation fault 11
-  // len = json(buf64, "d|2");
+  // len = json(buf64, "f|2");
   // printf("%s\n", buf64);  // gonna be random value converted from 64-bit number
 
   len = json(buf64, "b|");
diff --git a/src/JsonLogger.h b/src/JsonLogger.h
index 9e37ca6..b8de63a 100644
--- a/src/JsonLogger.h
+++ b/src/JsonLogger.h
@@ -1,7 +1,6 @@
 #ifndef json_builder_h
 #define json_builder_h
 
-// stuff you should know
 #define json(buf, ...) build_json(buf, sizeof(buf), __VA_ARGS__, NULL)     // returns json length if all good, negative number if error
 #define jsonHeap(buf, size, ...) build_json(buf, size, __VA_ARGS__, NULL)  // same as json() but user supplies buffer size for malloc-ed buffer
 
@@ -17,15 +16,20 @@ extern "C" {
 #endif
 
 // define LOG_ID_KEY (e.g. -D LOG_ID_KEY="i") and implement getLogId() if you want to log id
+//#define LOG_ID_KEY "i"
 #ifdef LOG_ID_KEY
 extern const char* getLogId();
 #endif
 
-// define LOG_ID_KEY (e.g. -D LOG_TIME_KEY="t") and implement getLogTime() if you want to log id
+// define LOG_TIME_KEY (e.g. -D LOG_TIME_KEY="t") and implement getLogTime() if you want to log id
+//#define LOG_TIME_KEY "t"
 #ifdef LOG_TIME_KEY
 extern const char* getLogTime();
 #endif
 
+// define LOG_SOURCE_KEY (e.g. -D LOG_SOURCE_KEY="s") if you want to log source file, line # and function name
+//#define LOG_SOURCE_KEY "s"
+
 void logAddSender(void (*sender)(int level, const char* json));
 void logModifyForHuman(int level, char* json);
 
@@ -37,10 +41,6 @@ extern const char* LOG_LEVELS[];
 
 #define JSON_ERR_BUF_SIZE -1
 
-#ifndef EMPTY_KEY
-#define EMPTY_KEY "_"
-#endif
-
 #ifndef LOG_MIN_LEVEL
 #define LOG_MIN_LEVEL 1
 #endif
@@ -49,18 +49,18 @@ extern const char* LOG_LEVELS[];
 #define LOG_MAX_LEN 512
 #endif
 
-#ifndef LOG_LEVEL_KEY
-#define LOG_LEVEL_KEY "l"
-#endif
-
-#ifndef LOG_SOURCE_KEY
-#define LOG_SOURCE_KEY "s"
+#ifndef EMPTY_KEY
+#define EMPTY_KEY "_"
 #endif
 
 #ifndef LOG_FUNC_KEY
 #define LOG_FUNC_KEY "f"
 #endif
 
+#ifndef LOG_LEVEL_KEY
+#define LOG_LEVEL_KEY "l"
+#endif
+
 #define LEVEL_FATAL 5
 #define LEVEL_ERROR 4
 #define LEVEL_WARN 3
@@ -68,9 +68,13 @@ extern const char* LOG_LEVELS[];
 #define LEVEL_DEBUG 1
 #define LEVEL_TRACE 0
 
-// stuff you shouldn't know
+#ifdef LOG_SOURCE_KEY
 #define logJson(level, ...) \
-  if (level >= LOG_MIN_LEVEL) log_json(level, "", "s", __FILE__ ":" TOSTRING(__LINE__), "f", __func__, __VA_ARGS__, NULL)
+  if (level >= LOG_MIN_LEVEL) log_json(level, "", LOG_SOURCE_KEY, __FILE__ ":" TOSTRING(__LINE__), LOG_FUNC_KEY, __func__, __VA_ARGS__, NULL)
+#else
+#define logJson(level, ...) \
+  if (level >= LOG_MIN_LEVEL) log_json(level, "", __VA_ARGS__, NULL)
+#endif
 
 #define STRINGIFY(x) #x
 #define TOSTRING(x) STRINGIFY(x)
diff --git a/src/Logger.c b/src/Logger.c
index 7a29546..0a366a7 100644
--- a/src/Logger.c
+++ b/src/Logger.c
@@ -26,10 +26,12 @@ void logModifyForHuman(int level, char* mod) {
   str_replace(mod, buf, "");
 #endif
   str_replace(mod, "\",\"" LOG_LEVEL_KEY "\":", strlen(LOG_LEVELS[level]) == 5 ? "" : " ");
+#ifdef LOGO_SOURCE_KEY
   str_replace(mod, "\",\"" LOG_SOURCE_KEY "\":\"", " ");
   str_replace(mod, "\",\"" LOG_FUNC_KEY "\":\"", " ");
+#endif
+  str_replace(mod, "\\\"", "'");
   str_replace(mod, "\"", " ");
-  // mod[strlen(mod) - 1] = '\0';
 }
 
 void log_json(int level, const char* placeholder, ...) {
@@ -53,8 +55,11 @@ void log_json(int level, const char* placeholder, ...) {
 }
 
 #ifdef LOGGER_TEST
+
 // gcc -Os -DLOGGER_TEST '-DLOG_TIME_KEY="t"' src/*.c; ./a.out; rm ./a.out
 // gcc -Os -DLOGGER_TEST '-DLOG_ID_KEY="i"' src/*.c; ./a.out; rm ./a.out
+// gcc -Os -DLOGGER_TEST '-DLOG_SOURCE_KEY="s"' src/*.c; ./a.out; rm ./a.out
+// gcc -Os -DLOGGER_TEST src/*.c; ./a.out; rm ./a.out
 
 const char* getLogTime() {
   return "1970-01-01T00:00:00Z";
@@ -87,7 +92,7 @@ int main() {
   printf("\n");
   logDebug("log to terminal, but not to file");
   printf("\n");
-  logInfo("i|status", -1, "d|5pi", 3.14159, "log to both terminal and file");
+  logInfo("i|status", -1, "f|5pi", 3.14159, "log to both \"terminal\" and \"file\"");
   printf("\n");
   logWarn("Warning");
   printf("\n");