Heating/Cooling regulator

The “Heating/Cooling Temperature Regulator” (HTR) software for our AYAtec_ESPtronic-V1.2 board is used to regulate and monitor temperatures in the required area (home heating, garages, aquarium, terrarium, animal husbandry, swimming pool, whirlpool …). Depending on which version is loaded into the control module or what HW configuration the module has depends on how many independent spaces it will be able to regulate. You can choose from several configurations. All versions of the programs allow you to control heating or cooling. Each channel can be individually set to have a function.

There are many different temperature controllers on the market. The advantage of this version is the possibility of remote control and especially monitoring with the possibility of archiving the measured data. This is the main advantage and an important feature of the whole system. The price of the module is also very reasonable when comparing its capabilities. By monitoring the temperature, it is possible to determine and verify the correct function of the heating/cooling system and, if necessary, to check the central heat supplier or whether it is fulfilling its energy supply.

No hardware other than the ESP8266 module in any device or only the module itself is required to test the program. For example “ESP8266 LOLIN (WEMOS) D1 R2 & mini” for which our hardware is built. Although the program will not display the correct temperatures, it will work completely and you can test its use in your own network. Even by connecting the display directly to the SCL and SDA, it will also display the necessary information.

ESP8266 12 WeMos D1 Mini

Technology activity description

The breakdown of the individual versions of the program is as follows:

  • 1×2 – one relay and two thermometers. This simplest version of the program is designed for temperature control in one room. Relay Q1 is controlled from the value of thermometer T1. The second thermometer can be used as auxiliary information. For example, to measure the temperature of the heating circuit, which can give us feedback on the operation of the heating source. At the same time, it is possible to derive the approximate heat consumption from this temperature by a simple calculation. Or it is possible to measure a higher temperature and the like.
  • 2×4 – two relays and four thermometers. This version is designed for temperature control independently in two rooms. Relays Q1 and Q2 are controlled from the value of thermometers T1 and T2. The other two thermometers can be used as auxiliary information as described in version 1×2.
  • 3×7 – three relays and seven thermometers. This version is designed to control the temperature independently in three rooms. Relays Q1, Q2 and Q3 are controlled from the value of thermometers T1, T2 and T3. The other four thermometers can be used as auxiliary information as described in version 1×2.
  • 7×7 – seven relays and seven thermometers. The most powerful version of the program designed for temperature control independently in up to seven rooms. Relays Q1 to Q7 are controlled from the value of thermometers T1 to T7. Of course, if not all seven outputs are required, the thermometers can be used informatively as in previous versions.

Each of these SW versions requires the HW configuration required for the program. All schemes for each version of the programs are described below on this blog. Of course, if the configuration of the module is higher, it is possible to upload a SW version for a lower configuration and everything will work without problems. The advantage of the solution is that, depending on the required SW version, the unnecessary expansion part can be cut from the “AYAtec EPStronic V1.2” board and the unit inserted into a smaller Hammond box.

The regulation is designed for a temperature range in the range of -20 to + 130 o C. The temperature sensor used for the measurement is an NTC resistance with a value of 10k. Temperature accuracy in the range of 25 – 50oC is 1oC.

NTC Temperature Sensor

The operation of the program is as follows: After setting the required temperatures in various set time intervals, the control unit regulates the temperature by switching on the respective output relay. This output switching contact can then be instructed to start heating, for example for an electric or gas boiler, a heating circuit pump, a heat pump and the like. When the required set temperature is reached, the relay switches off, thus instructing to switch off the heating. The switching temperature hysteresis is 1 oC.

HTR technology diagram

A schematic illustration of the possible involvement of HTR technology is shown in the figures below. There are many uses for these versions of programs and hardware. It all depends on the need to heat anything in the temperature range that the unit allows.

HTR electronic wiring diagrams for PCBs for individual SW versions


For fully automated room temperature control, it is possible to use our printed circuit board AYAtec ESPtronic V1.2 equipped according to the documents below, including a program developed specifically for this purpose. A detailed description of PCB is in this blog.

The PCB does not need to be fitted with all the components on which it is designed. The diagrams shown above show all the necessary components that the software of each version of the program operates. After installing them, uploading the required version of the program and storing the PCB in a suitable box, all you need to do is connect and operate everything. In case of interest, it is possible to order the entire fully functional and revitalized control unit here.

In order to fully automate heating control, we have developed the software AYAtec_ESPtronic-V1.2_Heat_1.xx_xx.bin (“Heating Temperature Regulator” (HTR)) in several language versions and configuration versions. The software allows you to set all the necessary parameters to suit a large number of configurations and needs. All you have to do is download the required language version on this website, upload it to the control unit using the flash8266.exe program, connect it, configure the module correctly via WiFi and start it up. The “HTR” software is designed as a web client, which is controlled and configured via a web page integrated in the control unit. It is possible to connect as many temperature sensors to the input terminals as the installed SW version allows. They connect to inputs marked I1 – I7. Input I8 is not used for temperature measurement. An internal RESET button is also connected to this input. This would, in some circumstances, cause the module to reset unintentionally. Outputs Q1 – Q7 are controlled as follows: The sensor connected to input I1 controls Q1, input I2 controls Q2 and so on. Other unused inputs (temperature sensors) can be used for information purposes. For example, it is possible to place them on the heated pipe of the heated branch and thus recover the operating status of the heating circuit. All states of inputs and outputs can be sent to the MQTT broker, which makes it very effective to monitor the real behavior of the entire heating system. One of the thermometers is suitable for measuring the outdoor temperature. By entering the measured values ​​in the MQTT, it is possible to further evaluate and store for future use.

Quick guide

The software has four control options for each programmed circuit: Off, Auto, Standby and Manual. In the “Off” mode, the control for the given branch is switched off and does not regulate the temperature in any way. In “Auto” mode, there are four times for 24 hours and one temperature for the weekend + “Standby”. Within these four times, the desired temperature can be set independently for the set time range. Maintaining the set “Standby” temperature is active outside the set times or if the “Standby” mode is set in the menu. For example, during holidays or for other reasons when it is not necessary to heat the space to standard operating temperature. By switching to “Manual” mode, the temperature is constantly maintained at the set value. In the “Manual” mode, we can manually adjust the temperature to the desired (higher or lower) at any time without affecting the automatic mode. If a display is also connected to the PCB, it shows important information about the system status as well as the values ​​of some important parameters of the program. This helps a lot in checking the correct running of the program and settings or in identifying the problem. The software works without a connected display without restrictions.

Dimensionally, the website is designed to be displayed on a mobile phone. To set up or monitor functionality, the module must be connected to a WiFi network. By calling the IP address of the control unit, its page will be displayed, which has a main menu at the top. It consists of two basic units. One unit (core) provides all system functions such as connection to WiFi network, communication on the web, sending data to the server and a number of necessary system parameters. The operating instructions for the system kernel can be downloaded here. The second core provides the control of all “HTR” functions. Each item is preceded by a question mark icon. Hover over this icon to see a brief description of the item. If it is not necessary to further send or display data during operation, a WiFi connection is not required during operation. The entire operating instructions can be downloaded here.

Software menu – “Settings” for version 7×7 (palette LUCID)

Software menu – “System

MQTT protocol

There are two ways how to set control parameters. One is to use the basic website of the module through its connection to the module’s IP address and the other is to use the MQTT data shared also through Node-RED, a flow program editor. Prior to its very use, the communication must be first enabled in the SYSTEM/WiFi program menu. The module sends all the important information such as water temperature, output conditions and the parameters set to the MQTT broker. There, such information is processed, and graphical and textual deliverables are generated. Especially effective is the monitoring of the very activity of the module, its IO ports, and the overall equipment activity. Thus, it is possible to optimize very effectively the operation through suitable setting of the system. In the lower part of the article, it is possible to download the flow for Node-RED.

Method of connecting whole control system HTR to the computer network

Partial Node-RED scheme for HTR software

Node-RED web screen with HTR module activity

Node-RED flow for software HTR version 3×7

A very effective option for monitoring and setting the basic parameters of the control unit program is using a mobile phone. The “IoT_MQTT_Panel” program for Android phones makes this option fully available. Below is a picture of the possible layout of the required parameters on the mobile phone screen. By setting the necessary elements of the program and saving it on the screen, the mobile phone becomes fully capable of controlling and monitoring the entire unit. The configured data for the program “IoT_MQTT_Panel_Pro” can be downloaded here. The difference between “IoT_MQTT_Panel” and “IoT_MQTT_Panel_Pro” is, among other things, the ability to export and import generated data, allowing the created work to be backed up in case of data transfer to another device or simply backed up in case of mobile phone failure and unwanted data loss.

Control module own fabrication

With a little dexterity and basic experience in the field of electronics, the control module can also be assembled according to our description and diagram. If you are really skilful and also have the necessary technical equipment (soldering iron, components for development, skill and sufficient experience), you can also connect the entire scheme on the development board. A similar example is in the photo below.

But with our PCB “AYAtec_ESPtronic-V1.2”, the result of your work will be professional. Depending on your options and experience, it is possible to choose more methods when obtaining a control unit. Depending on the complexity of production, there are several options to choose from:

1 – The cheapest yet the most challenging method is to get a printed circuit made for you, buy all the required parts, mount the board, program the ESP8266 module and put that all in a box. The documents necessary for the completion of the above, a list of parts included, form part of this web. As the production and the mounting of SMD parts on the printed circuit can be ordered from one supplier, the remaining activities make the assembly and activation much easier.

AYAtec ESPtronic V1.1 with all components for HTR 3×7

2 – Another method is to buy the whole set of parts configured for the Heat software in our e-shop. This all is then assembled and activated as in the case of the first method. From the effectiveness point of view, this method is highly optimal as there is no need to by parts from several different places and it is also guaranteed that all the parameters of the delivered parts are correct.

Kit for HTR 7×7

Set of parts for Heat control unit

3 – Simpler and at the same time more costly method is to buy a readymade assembled and programmed control module. This method is, at the same time, more comfortable as it is only necessary to connect the module as per the specification to make it readily available. The front panel of the Heat control unit, specification of input and output connection included, is shown below.

Regulator HTR 7×7

Front panels of the control units with connection description

HTR 1×2
HTR 3×7
HTR 2×4
HTR 7×7

Basic parameters:
Supply voltage: + 12V
Current consumption: 0.5A max.
Measured values: temperature range -20 – + 130oC
Display resolution: 128x64px


This is the third manual that describes room temperature control. We are continuing to improve the program’s features. If you find any shortcomings or have suggestions for improvement, let us know. We will try to incorporate your requirements into the program as soon as possible.

Files to download

Below is a list of data that need to be downloaded for the AYAtec ESPtronic V1.2 board.

Name Resource Link
Wiring diagram 7×7 Wiring diagram of components for the Heat control unit required for software “Heating 7×7 ESPtronic WiFi”. Download
Wiring diagram 3×7 Wiring diagram of components for the Heat control unit required for software “Heating 3×7 ESPtronic WiFi”. Download
Wiring diagram 2×4 Wiring diagram of components for the Heat control unit required for software “Heating 2×4 ESPtronic WiFi”. Download
Wiring diagram 1×2 Wiring diagram of components for the Heat control unit required for software “Heating 1×2 ESPtronic WiFi”. Download
Software “Heat 7×7” Download link for full-featured software to control Heat technology. For 14 days, the software is fully functional without restrictions. If further use is required after the trial period, a license must be purchased and activated. Download