Why did I make it?

A friend of mine which has a pet snake was constantly turning on/off a lamp heater, a water fountain and a hot stone to keep the ambient of it's snake within the required values. He asked if I could build a system to automate the task.

What are the features?

An ESP32 is the processor for this board which means you not only get lots of processing power but also a Wifi/BT interface. There are 4 relay controlled outputs, each channel has 1 NO contact and 2 NC contact and is protected with a fuse. The board is powered via on-board isolated AC-DC converter module capable of 5V 1A which is more than enough for this system. In terms of input you have two dedicated 1-Wire interface ports, one I2C interface available via 0.1" pin header, multiple GPIO available via 0.1" pin header, multiple analog inputs available via dedicated 0.1" pin header. For storing of variables as well as potential data logging there is an on-board I2C EEPROM memory.

How do you write software/code for this board?

You can write code in pretty much any development environment that supports the ESP32 but you can checkout the example code which is written in Arduino using PlatformIO and Visual Studio. This is just an example code and is provided AS IS without warranty of any kind.

How do you load code to the ESP32

The system features the VOLTLINK interface for programming. You will need a JST-SH pigtail to connect to a VoltLink programming board or any other ESP32 upload tool that features IO0 and EN signal auto-reset circuitry. Alternatively you can load code via OTA after flashing the board with firmware that supports OTA.

Safety Warning

This control board uses mains voltage so you need to know what you are doing, otherwise, there is a high risk of electrical shock and/or fire. This is a serious topic, if you are not sure what you are doing, ask for help from an electrician. Every connection should be double checked before applying mains power.

The 5V power brick which powers the control board is isolated but the relay control section only relies on the galvanic isolation provided through the relay construction and while the board is powered from mains there are still exposed points on the board which are mains connected. I strongly recommend powering the board externally with 5V via the provided test points while doing development work and moving to the final circuit powered from mains input only after code development and upload to board is complete.

Specs

• Controller section input voltage: 110V-250V AC.
• Controller section input current: 0.1A.
• Controller section over-current protection: 0.25A slow blow.
• Output relay voltage: AC or DC 250V max.
• Output relay current: 5A max per channel, protected with 6.3A fuse.

What you get with your order

You will get 1 x assembled controller board with 240V rated fuses installed and 1 x JST-SH pigtail for the VoltLink programming port. If you are using the controller board on something other than 240V mains, fuses should be replaced accordingly. If you would like to position the connectors differently and have them shipped un-assembled please mention this when placing the order, otherwise they will be soldered like shown in the images.

What else do you need to get you started?

You will need some sensors to build an aquarium/terrarium because first you sense the environment and then you turn on the heater or a water fountain to adjust for it. I would recommend starting with a DHT22 1-Wire interface sensors.

You will need to do some mains wiring to connect power to J1 to power the controller board as well as run the live wire for each of the items you are trying to control through each relay channel. I recommend doing the connections with Wago 221 series connectors.

Known issues in revA

• Power brick module footprint is wrong so it needs to be installed on the bottom side of the board. The board will come fully assembled so you don't need to worry about this.
• There are no mounting holes.
• Fitting the board inside the intended enclosure required some adjustments on the round cutouts. This is something to consider if you want to use the same enclosure but if you plan to install this in a larger plastic enclosure, it shouldn't be a problem.

Shipping delay & exception notice

Because of the current global situation I will not be able to ship to a list of countries as decided by the postal operators. Long delays for delivery are expected especially when shipping overseas to places like the US & Australia.