ESP WiFi relay project – preview previewed a WiFi controllable relay board using commonly available low cost hardware from sources like eBay and Aliexpress.
The stimulus for the project is a remotely WiFi controllable relay for reset function in a remote controlled ham station, basically to recover operation of some system element by bouncing the power.
The information presented here applies to development v0.2.
- support typical multi channel relay boards;
- ESP8266 and ESP32 firmware versions;
- WiFi credentials programmable via a captive web interface;
- DHCP or static IP;
- mDNS responder;
- flexible configuration stored as json file in on-board LittleFS file system;
- optional authentication to secure remote access.
Above is a ESP12F_Relay_30A X2_V1.1 relay board (~$20 inc shipping) deployed for field testing. This board has a switched mode power supply on board and will run on 7-28VDC. In this application, the AC circuit is wired through the NC contacts, and the relays are operated to break the power. Normal operation is with the relays released, and current consumption @ 13.8V is 30mA.
The underside of the board shows ample separation and isolation of tracks that might be used for 230VAC switching.
This board (like most) does not incorporate a USB programmer interface
Above, a programmer is connected to it as shown above and described in more detail at WiFi relay controller (ESP8266, ESP32).
In this instance, the module obtains WiFi credentials using the inbuilt captive portal, once connected to an AP, it is configured to obtain its IP address by gateway DHCP, that address is reserved in the gateway, and a ‘virtual server’ is configured on the gateway to redirect an inbound request on port 8001 to the module (on port 80). This allows control of the board from off-site across the Internet using a browser on a desktop computer, tablet or smartphone. That connection is secured with user and password of course.
It has already proven its worth in allowing recovery from a computer freeze without attending the site.
The project is a work in progress, documentation as it evolves at WiFi relay controller (ESP8266, ESP32).