Tinkering; Like Guntering for the Connected Generation.

Been Looking more at the LoRa Devices. I've purchased a few bits and I'm waiting for them to arrive.
In the mean time I've been tinkering with some devices that I already have using the MySensors.org libraries.

The MySensors Library supports a few different radio transceivers like the nrf24l01 (a 2.4GHz transceiver) and RFM95 (a LoRa device). I already had some nrf24l01 transceivers and as the sketches and wiring are very similar I started to convert my ESPHome based oil tank monitor to MySensors.


IMG_20200613_082800 by Emaherx, on Flickr

It turns out the the NodeMCU ESP32 is not a great choice for battery powered sensors as it dose not support the sleep function in MySensors, however it works fine as a USB powered sensor and the USB port is also useful for as a serial monitor for debugging. It will be straight forward to port to an Arduino Pro Mini if battery powered is required for remote sensors.

Even without the LoRa transceivers I'm fairly impressed with the range of the nrf24l01 and has proven to be more reliable than the WiFi signal I'd previously been using with the ESPHome based node.

MySensors Distance SerialMon by Emaherx, on Flickr

#define MY_DEBUG
#define MY_RADIO_RF24
#define MY_NODE_ID 42
#define MY_RF24_CHANNEL  91


#include <SPI.h>
#include <MySensors.h>  
#include <NewPing.h>

#define SENSOR_NAME "Distance Sensor"
#define SENSOR_VERSION "1.1"

#define CHILD_ID 1  // Each radio node can report data for up to 254 different child sensors. You are free to choose the child id yourself. 
                    // You should avoid using child-id 255 because it is used for things like sending in battery level and other (protocol internal) node specific information.
#define TRIGGER_PIN  16  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     4  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 300 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.
// unsigned long SLEEP_TIME = 5000; // Sleep time between reads (in milliseconds)


NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.
MyMessage msg(CHILD_ID, V_DISTANCE);
int lastDist;
bool metric = true;

void setup()  
{ 
  metric = getControllerConfig().isMetric;
}

void presentation() {
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo(SENSOR_NAME, SENSOR_VERSION);

  // Register all sensors to gw (they will be created as child devices) by their ID and S_TYPE
  present(CHILD_ID, S_DISTANCE);
}

void loop()      
{ 
  // use the build-in digital filter to discard out of range pings
  int echoTime = sonar.ping_median(10);
  int dist = metric?sonar.convert_cm(echoTime):sonar.convert_in(echoTime);
  Serial.print("Ping: ");
  Serial.print(dist);
  Serial.println(metric?" cm":" in");

  if (dist != lastDist) {
      send(msg.set(dist));
      lastDist = dist;
  }

  //sleep(SLEEP_TIME); commented out, won't compile for ESP32 used wait(5000); instead.
  wait(5000);
}