Added TTGO-T-Beam board + option to send ADC values in volt (#863)

* Added Voltage measure option
* Added TTGO Beam with Battery voltage measure

Author: hallard

main/ZsensorADC.ino

@@ -54,10 +54,32 @@ void MeasureADC() {
     } else {
       if (val >= persistedadc + ThresholdReadingADC || val <= persistedadc - ThresholdReadingADC) {
         Log.trace(F("Creating ADC buffer" CR));
+#  if defined(ADC_DIVIDER)
+        const int JSON_MSG_CALC_BUFFER = JSON_OBJECT_SIZE(2);
+#  else
         const int JSON_MSG_CALC_BUFFER = JSON_OBJECT_SIZE(1);
+#  endif
         StaticJsonBuffer<JSON_MSG_CALC_BUFFER> jsonBuffer;
         JsonObject& ADCdata = jsonBuffer.createObject();
         ADCdata.set("adc", (int)val);
+#  if defined(ADC_DIVIDER)
+        float volt = 0;
+#    if defined(ESP32)
+        // Convert the analog reading (which goes from 0 - 4095) to a voltage (0 - 3.3V):
+        volt = val * (3.3 / 4096.0);
+#    elif defined(ESP8266)
+        // Convert the analog reading (which goes from 0 - 1024) to a voltage (0 - 3.3V):
+        volt = val * (3.3 / 1024.0);
+#    else
+        // Asume 5V and 10bits ADC
+        volt = val * (5.0 / 1024.0);
+#    endif
+        volt *= ADC_DIVIDER;
+        // let's give 2 decimal point
+        val = (volt * 100);
+        volt = (float)val / 100.0;
+        ADCdata.set("volt", (float)volt);
+#  endif
         pub(ADCTOPIC, ADCdata);
         persistedadc = val;
       }

platformio.ini

@@ -49,6 +49,7 @@ extra_configs =
 ;default_envs = esp32-m5stick-cp-ble
 ;default_envs = esp32-m5atom
 ;default_envs = ttgo-lora32-v1
+;default_envs = ttgo-t-beam
 ;default_envs = nodemcuv2-rf
 ;default_envs = nodemcuv2-rf-cc1101
 ;default_envs = nodemcuv2-somfy-cc1101
@@ -497,6 +498,36 @@ build_flags =
   '-DZgatewayLORA="LORA"'
   '-DGateway_Name="OpenMQTTGateway_ESP32_LORA"'
 
+[env:ttgo-t-beam]
+# See version pinout differences here
+# https://www.thethingsnetwork.org/forum/t/big-esp32-sx127x-topic-part-3/18436
+platform = ${com.esp32_platform}
+board = ttgo-t-beam
+lib_deps =
+  ${com-esp.lib_deps}
+  ${libraries.ble}
+  ${libraries.lora}
+build_flags =
+  ${com-esp.build_flags}
+  '-DZgatewayLORA="LORA"'
+  '-DZgatewayBT="BT"'
+  '-DGateway_Name="OpenMQTTGateway_ESP32_BLE_LORA"'
+  
+  '-DLED_RECEIVE=21' # T-BEAM board V0.5
+#  '-DLED_RECEIVE=14' # T-BEAM board  V0.7
+#  '-DLED_RECEIVE=4' # T-BEAM board  V1.0+
+  '-DTimeLedON=0.05'
+  '-DLED_RECEIVE_ON=1' # Set 0 for board V1.0+
+
+  # for V0.5 and V0.7 ONLY (V1.0+ as onboard AXP202 dedicated chip, need driver)
+  # it's a 100K/100K divider (so 2 divider) and connected to GPIO35
+  '-DZsensorADC="ADC"'
+  '-DADC_GPIO=35'
+  '-DADC_DIVIDER=2'
+  # Reading battery level every minutes should be more than enought
+  '-DTimeBetweenReadingADC=60000' 
+  
+  
 [env:nodemcuv2-all-test]
 platform = ${com.esp8266_platform}
 board = nodemcuv2