Cistern pump controlled by Wemos D1 Mini via MQTT

Summer, sunshine, dry flower beds but a rainwater cistern. But having to irrigate it by hand every morning and evening is time-consuming. To make better use of this time, we have installed a Garden Micro Drip System, which is fed through the existing rainwater cistern. Gardena offers irrigation computers, but these switch the water supply on and off via a magnetic contact. The pump would therefore run permanently. For this reason, another solution had to be found that would switch the pump on and off by itself.

Irrigation System

There are many irrigation systems, after some research my wife and I decided to use the Gardena Micro Drip System.

We are still very pleased with this. In order to increase the life span, we dismantle the 3/16-inch components including drippers and spray nozzles over the winter months, the 1/2-inch components remain in the garden, are blown water-free by a compressor to avoid defects caused by frost.


The following solution is based on a D1 Mini with Relay as hardware, MQTT as connection protocol, MQTTDash as client and Node-RED for the automated flow as follows.

  • Connects to the Wireless Access Point / Wi-Fi Router
  • Securely connects to the MQTT Broker (TLS)
  • Subscribes to the desired MQTT topics
  • Handles incoming MQTT messages
  • Controls ESP8266 Chip Level Data Pins
  • Sends a heartbeat signal to the MQTT broker periodically
  • Switches a double relay for cistern pump and a socket
  • Checks the status of the cistern pump and switches it off automatically after a certain time (threshold value) if no switch-off signal is received by the specified time (protection against garden flooding)

The complete project documentation can be found here: