I unhooked the DHT and got this
0J2%1"=2I=5"!Q9M=Ij
ERROR: Failed to read from DHT sensor!
ERROR: Failed to read from DHT sensor!
ERROR: Failed to read from DHT sensor!
ERROR: Failed to read from DHT sensor!
Now my DB was and still is connecting to my wifi network but not getting the attempting MQTT connection is of concern I think
This is fine. The code just publishes MQTT messages if there are valid measurements:
if (isnan(h) || isnan(t)) {
Serial.println("ERROR: Failed to read from DHT sensor!");
return;
} else {
publishData(t, h);
}
Oh, a connection should be possible. Just don’t expect messages of sensor readings.
If I unplug and then plug the db back in I keep getting that first line of crazy stuff then the warning message
+4
ERROR: Failed to read from DHT sensor!
ERROR: Failed to read from DHT sensor!
Should I re-upload the sketch to the db?
Slowly. Crazy stuff on boot-up is fine. I just attached a DHT22. This is the output if everything works fine:
Okay, my measurements are a bit crazy. 
But it’s more or less a proof of concept.
Okay, I wired up a DHT11, too and changed the define:
#define DHTPIN D6
#define DHTTYPE DHT11
The output is
⸮Hh⸮⸮⸮յ⸮0x2d
csum 0x2d
vdb886
INFO: Connecting to Greendale
.......
INFO: WiFi connected
INFO: IP address:
192.168.130.56
INFO: Attempting MQTT connection...INFO: connected
{
"temperature": "23.00",
"humidity": "35.00"
}
INFO: Closing the MQTT connection
INFO: Closing the Wifi connection
And this is a picture of the setup:
I make the same change to the sketch and get an error stating
D6' was not declared in this scope
Wow. The sketch just doesn’t work out of the box. The serial output looks fine but the MQTT server doesn’t receive the messages.
$ mosquitto_sub -v -h localhost -t '#' -u username -P password
Does not produce any output. The log of mosquitto shows a timeout because the device is too slow:
1505030238: New connection from 192.168.130.56 on port 1883.
1505030238: New client connected from 192.168.130.56 as office_dht22 (c1, k15, u'sensors').
1505030260: Client office_dht22 has exceeded timeout, disconnecting.
Please tell me the full name of your development board / product you are using. You must select the right board at “Tools → Board → Wemos D1 mini (just for example)”.
This is the board.
NodeMCU ESP8266 WiFi Lua Development Board + Support CP2102 V1.0 IoT Module
changes to sketch verified correctly when I remembered to change the board type (yet another mistake by me, sorry)
I’ll try to upload to the db and rewire accordingly
ok, did the upload successfully and now nothing from the Serial Monitor
Did you wire up the sensor properly? If the grid points to you and the pins to the bottom:
I skipped the pull-up but it’s not recommended: http://www.micropik.com/PDF/dht11.pdf
it’s a 3 pin dht11 sensor so pin 1 is the data and it’s got the 4.7k ohm resistor attached and then on to D6
Pin 2 is to power and pin 3 is to GND
Does it looks like this one?
This is the one I have
Do you have a multimeter? Can you verify the circuit? Just use the continuity tester and verify the connection between the pin header and the sensor pins.
sadly I do not have one available currently
To summarize: If your sensor is properly wired and not destroyed you must see all log messages (mentioned above). As long as it doesn’t work please keep the wires as short as possible. If you can see proper measurements in the serial output you can care about the next step (MQTT). For me (with! the mentioned patch) it’s working now:
$ mosquitto_sub -v -h localhost -t '#' -u user -P password
office/sensor1 {"temperature":"24.00","humidity":"35.00"}
office/sensor1 {"temperature":"24.00","humidity":"35.00"}
office/sensor1 {"temperature":"24.00","humidity":"35.00"}
This is my setup:
configuration.yaml :
sensor:
- platform: mqtt
state_topic: "sensor/livingroom/lux"
name: "Lux Livingroom"
qos: 0
unit_of_measurement: "Lux"
- platform: mqtt
state_topic: "sensor/livingroom/humidity"
name: "Humidity Livingroom"
qos: 0
unit_of_measurement: " %"
- platform: mqtt
state_topic: "sensor/livingroom/temperature"
name: "Temperature Livingroom"
qos: 0
unit_of_measurement: " ºC"
- platform: mqtt
state_topic: "sensor/livingroom/battery"
name: "Battery Sensor Livingroom"
qos: 0
unit_of_measurement: " V"
(Maybe it’s not necessary with “double” -platform statement? But it works.)
Hardware:
ESP8266(Wemos D1 mini), DHT22, BH1750 light sensor and chargeable battery with the following .ino file:
#include <DHT.h> // Temp_hum sensor
#include <BH1750.h> // Lux Sensor
#include <Wire.h>
#include <ESP8266WiFi.h> //ESP WIFI
#include <PubSubClient.h> //MQTT
ADC_MODE(ADC_VCC);
const char *ssid = "yourSSID";
const char *pass = "yourPWD";
const int sleepTimeS = 300; //define deep sleep time
#define DHTTYPE DHT22
#define DHTPIN 2
#define MQTT_VERSION MQTT_VERSION_3_1_1
#define mqtt_server "yourMQTTServer"
#define mqtt_user "MQTTUser"
#define mqtt_password "MQTTPWD"
#define temperature_topic "sensor/livingroom/temperature"
#define humidity_topic "sensor/livingroom/humidity"
#define battery_topic "sensor/livingroom/battery"
#define lux_topic "sensor/livingroom/lux"
BH1750 LightSensor;
DHT dht(DHTPIN, DHTTYPE);
WiFiClient wifiClient;
PubSubClient client(wifiClient);
void setup() {
Serial.begin(115200);
Wire.begin();
LightSensor.begin();
dht.begin();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, pass);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
client.setServer(mqtt_server, 1883);
}
void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
Serial.print("Attempting MQTT connection...");
// Attempt to connect
// If you do not want to use a username and password, change next line to
// if (client.connect("ESP8266Client")) {
if (client.connect("ESP8266Client", mqtt_user, mqtt_password)) {
Serial.println("connected");
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
uint16_t Lux = LightSensor.readLightLevel();
float h = dht.readHumidity();
float t = dht.readTemperature();
float V = ESP.getVcc();
Serial.print("Temperature: ");
Serial.print(t);
Serial.print(" degrees Celcius, Humidity: ");
Serial.print(h);
Serial.print("%. ");
Serial.print("Voltage: ");
Serial.print(V/1000);
Serial.println(" V");
Serial.print(Lux);
Serial.println(" Lux");
client.publish(lux_topic, String(Lux).c_str(), true);
client.publish(temperature_topic, String(t).c_str(), true);
client.publish(humidity_topic, String(h).c_str(), true);
client.publish(battery_topic, String(V/1000).c_str(), true);
// Sleep
Serial.println("ESP8266 in sleep mode");
ESP.deepSleep(sleepTimeS * 1000000);
}
This works like a charm…