Summary of ESP8266 Standalone WiFI Relay Control
Summary: This guide shows how to control a relay using an ESP8266 (ESP-01) in standalone AP mode (ESP broadcasts its own SSID, IP 192.168.4.1) via a web UI. It covers required hardware, software (NodeMCU flasher and ESPlorer), and powering the module safely (use external 3.3V supply or DC-DC buck converter, calibrate to 3.3V) plus recommendations for a relay driver.
Parts used in the ESP8266 Standalone WiFI Relay Control:
- ESP8266 module (ESP-01)
- 3.3V or 5V power supply (module uses 3.3V)
- 12V power supply
- Any Wi-Fi enabled device
- FTDI USB to TTL adapter
- Breadboard
- Connecting wires
- DC-DC Buck converter (optional, to power the module)
- 1N5408 diode (optional)
- Multimeter (optional)
- Relay driver (3V, preferably with optocoupler)
- NPN transistor and relay (optional alternative to relay driver)
AIM
- To control a relay switch using esp8266 in standalone mode(without arduino,pic or any other Micro-controller) via Web-UI
- The ESP broadcasts its own SSID.It does not connect to a router.local IP address of esp is 192.168.4.1
Step 1: Gather Hardware
- ESP 8266 (There are a lot of variants available in the market.for this tutorial lets just use the esp-01).If you are curious about the different variants click this link.
- 3.3v/5v power supply (depending on your module.My esp 01 uses 3.3v.Its very important that you have and external power source.More on this later),12 v power supply
- Any WI-Fi enabled device.
- FTDI USB to TTL adapter like this
- Bread Board
- Some connecting wires
- DC-DC Buck converter(optional.To power the module.)
- 1N5408 diode(optional)
- A multi meter (optional)
- Relay Driver(3v in my case) I recommend you to get the one withoptocouple like this
- you can build the relay driver on your own if you wish to with an npn transistor and a relay,the circuit is provided here.but i recommend you get a relay driver
Step 2: Gather Software
- Node MCU Flasher – Node_MCU.7z
- ESPlorer(The IDE to load Lua script to the module) – ESPlorer.7z
Step 3: Setting Up Power Supply
This step is important.
Some FTDI USB to TTL converters have a 3.3 v power supply build into it.To avoid unnecessary confusions.Don’t try to power the module from the power supply of the USB to TTL converter. It Just wont work guys
Methods to power it:
- Use a 3.7 v battery from your old phone.(an additional 0.4v wont damage your module)
- Use a DC to DC buck converter like this
Calibrating the Buck Converter
Make connections as shown in the Diagram
- Connect a 12v power supply to the input via a diode(protection)
- Switch to DC voltage measurement in you multi meter and connect it to the output of the Buck converter
- adjust the variable resistance on the buck converter till the multi meter reads 3.3v
Read more: ESP8266 Standalone WiFI Relay Control
- What is the ESP8266 IP address in standalone mode?
The local IP address of the ESP in standalone mode is 192.168.4.1. - Can the ESP8266 operate without an external microcontroller?
Yes, the project controls a relay using the ESP8266 in standalone mode without Arduino, PIC, or other microcontrollers. - How does the ESP8266 provide network access?
The ESP broadcasts its own SSID and acts as an access point for Wi-Fi devices. - What software is needed to load Lua scripts to the ESP8266?
ESPlorer is used as the IDE to load Lua scripts to the module. - What tool is recommended to flash NodeMCU firmware?
Node MCU Flasher (Node_MCU.7z) is listed for flashing the firmware. - How should the ESP8266 be powered?
Use an external 3.3V power source or a calibrated DC-DC buck converter; do not rely on the FTDI USB-TTL 3.3V supply. - What is a recommended relay interface?
A 3V relay driver with an optocoupler is recommended; alternatively build a driver with an NPN transistor and a relay. - How do you calibrate the buck converter for the ESP8266?
Connect 12V input via diode, measure DC output with a multimeter, and adjust the buck converter until it reads 3.3V.
