Build with ESP8266 ESP-01 Arduino IDE (https://github.com/esp8266/Arduino)

# turn off relay
curl -X PUT http://eclipse.mqttbridge.com/murilo/esp/rele/off

# turn on relay
curl -X PUT http://eclipse.mqttbridge.com/murilo/esp/rele/on

# control relay from Android
https://play.google.com/store/apps/details?id=at.tripwire.mqtt.client&hl=en
publish murilo/esp/rele/on   - turn on relay
publish murilo/esp/rele/off  - turn off relay



See source code...