Basic ambient temperature and humidity sensor

Manuel Fegerl 15/04/2019
Wifi temperature sensor and humidity sensor to build yourself (DIY) without soldering with iOS and Android App for NodeMCU ESP8266 with DHT11 sensor

Introduction

With the help of this guide you can easily and quickly build a temperature and humidity sensor that transmits the data via wifi to your (Android and iOS) smartphone and helps to protect your basement or bathroom from mold, for example. This project uses a NodeMCU Amica v2 (based on the ESP8266 microcontroller) and a DHT11 sensor. The current measurement data is also shown on the OLED display.

So that you don’t have to program it yourself, you can simply copy the Sensate firmware to the microcontroller, at the end of the manual you’ll learn more about it. With the help of the Sense App you can then easily access your data at any time (and from anywhere) and see e.g. the daily course of temperature and humidity.

Typical applications for this project:
– Temperature and humidity monitoring for the basement
– Temperature and humidity monitoring for the bathroom
– Temperature and humidity monitoring for small animal enclosures (e.g. hens or hares)
– Temperature and humidity monitoring for the holiday home


Component list

1
Breadboard (z.B. 400 Pin)
1
NodeMCU Amica v2 (Bridge)
1
1,3 Zoll I2C OLED Display
1
DHT11 Sensor
1
Jumper wires

Best used with

Quick configure with

No tools or skills needed


Connecting the bridge to the breadboard

Take the broadboard and bridge as shown and put the bridge on the red marked skirting boards. Please make sure that the USB port of the bridge is pointing downwards. The bridge must then be plugged into the pins labeled as follows:

– Left pin header: a: 16 to 30
– Right pin header: h: 16 to 30


Connect sensor module to breadboard

In this step, the sensor for temperature and humidity is connected to the broadboard. The 3 pins are connected to j: 2 to 4. Make sure that the board is on the right and the pins on the left.


Connect the display to the breadboard

Now the display follows. The display will use the same cable for the positive voltage of the power supply (VC) as the sensor, therefore it shares row 4 with the sensor. The display must be aligned so that the pins are on the right. These are then plugged into the socket strips g: 4 to 7.


Connect sensor module with bridge

Here the sensor is connected to the bridge. This supplies the sensor with power and connects it to the data pin D4 of the bridge. For this a cable is plugged in as follows:

i: 2 to j: 22 (corresponds to label GND on bridge)
i: 3 on j: 20 (corresponds to label D4 on Bridge)
i: 4 on j: 21 (corresponds to label 3.3V on bridge)


Connect display to bridge

Since the display was already powered in the last step, only the data lines connected to D1 and D2 of the bridge are missing for the display. To do this, plug in one cable at a time as follows:

i: 6 to j: 17 (corresponds to label D1 on bridge)
i: 7 on j: 18 (corresponds to label D2 on Bridge)
i: 5 on i: 22 (corresponds to GND label on bridge)


Result

If your microcontroller (bridge) has not yet been loaded with the Sensate firmware, follow this guide. After that the device is fully functional and can now be configured and used with the Sense App.

Within the Sense App you can then view the current measurement data as well as the time history. If the sensor is placed e.g. in the bathroom, you will clearly see the temperature and humidity curves when someone showered or when the room has been ventilated. If you want to be informed automatically about the exceeding or falling below of limit values (e.g. in case of danger of mould) you can do this with the help of the IFTTT integration.

To protect the components from dust and dirt, we recommend the installation in a plastic housing. This is possible even with little skill and equipment. Just have a look at our intermediate skill tutorial.