YABC - Yet Another Blynk Controller - IoT Cloud Temperature and Humidity Controller, ESP8266

Introduction: YABC - Yet Another Blynk Controller - IoT Cloud Temperature and Humidity Controller, ESP8266

About: A keen surfer, water-sports and extreme sports enthusiast. I spent most of my spare time outdoors or inside the garage, home brewing or some random electronics

Hi Makers,

I recently started growing mushrooms at home, Oysters mushrooms, but I have already 3x of this controllers at home for Fermenter Temperature control for my home brew, wife is also doing this Kombucha thing now, and as a Thermostat for Heater control. The concept is the same for a lot of different application, green houses, home brewing, spa pools, heaters and so forth.

I believe temperature control is one of the most popular applications of IoT and Blynk therefore decided to build this project and share with you. The thing that annoys me the most is those flimsy terminals on cheap board that do not hold cables properly, leaving live wires exposed and on top of that, all my attempts to find "nice looking" cases for the DIY projects using different boards failed, and never tried 3D printing.

**PCB features:**

  • ESP8266 ESP-WROOM-02 based;
  • Local OTA enabled;
  • WS2812 RGB LED;
  • TX and RX pins exposed on a 3-pin male header, for programming and monitor;
  • 3 x 250VAC/30VDC 7A AgSnO2 relays;
  • Plug-in screw terminals;
  • Power Supply 9~12VDC(not included);

**Probes Supported**

  • BME280;
  • HTU21D;
  • SHT3x;
  • AM2315; (My personal favorite because of its shape)
  • DS18B20 one-wire;
  • NTC Thermistor (not really a good option);


As the ESP8266 has some peculiarities about which pin can be used as a sensor and as a Relay as it changes its state during booting I changed some pins around as follows:

#define NTCINPUT              A0
#define SDA_PIN               12
#define SCL_PIN               14       //DS18B20 DATA WIRE GOES HERE AS WELL
#define RLY1_PIN              4        //Active HIGH
#define RLY2_PIN              5        //Active HIGH
#define RLY3_PIN              15       //Active HIGH
#define BOARD_BUTTON_PIN      0        //Active LOW
#define BOARD_LED_PIN_WS2812  13

**If you want to buy one and help me quit my day time job ;) ----> MY Store on Tindie

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Step 1: Blynk Mobile App

This is an extended version of Blynk App you will need to buy some energy as the App requires 4,400 energy points, you'll find a simpler version at: YABC Simple and you won't need to buy energy initially.

Download Blynk App: Getting Started with Blynk

  1. Download Blynk App: http://j.mp/blynk_Android or http://j.mp/blynk_iOS
  2. Touch the QR-code icon and point the camera to the code below
    • Enjoy my app!

    Step 2: How to Start

    The firmware has all you need to control Heating and Cooling using Blynk Cloud App.

    Press and hold the button for 3 seconds or more and the board will start the Access point mode "YABC-xxxxx" followed by the 6 last digits of the board MAC address:

    Connect to the network (no password required) and the Captive Portal should start automatically, if it doesn't start, please go to your internet browser and go to the following configuration screens will be available, insert your WiFi credentials, Blynk Authentication number retrieved from the App when clonning the above project and select your temperature probe and save.

    After saving the configuration the board will restart and connect to the WiFi informed and if everything is right you can start using your Blynk App and Control the temperature with your own IoT controller.

    Step 3: How Does the Set-up Look Like?

    I'm using a 60W Thermoelectric Peltier Cooler Refrigeration Semiconductor Cooling System Kit Cooler Fan Finished Kit in order to control the Heating and Cooling as the Peltier can do both by changing its polarity, I know it's not the most efficient way but it does the job.

    Peltier is quite power hungry so you'll need a "high current" 12VDC power supply something like this: AC110V 220V To DC12V Power supply 12V 10A please make sure to select a High Capacity one as the Peltier needs 60W and you still need to power fan and the ESP8266 board + the power supply specs are not too reliable.

    I'm using external relays in order to protect the main board (external relays are cheaper than replacing the main board if something goes wrong) and also to change the polarity, if you are using the Peltier for Cooling **OR** Heating **only** or have 2 sources you don't need them.

    **The wiring diagram goes like this:**

    Step 4: And How About the Code?

    Here you go, but you'll also need the adapted untrol_WiFiManager Library from GitHub. AND many others.

    The code looks funny when posted here but you can see at My Github Page

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