liderbug wrote:https://smile.amazon.com/WHDTS-ESP8266-Channel-Transmission-Distance/dp/B071WWMMDD/ref=sr_1_4?ie=UTF8&qid=1529080001&sr=8-4&keywords=esp8266+relay+board
Requires 5V in - has onboard 3.3 reg.
Ah, but that's not an ESP-01 (yeah, there's one placed on the board, but it's not what you told us).
Still you need to be certain that your PSU is able to provide a stable 5V at 500mA for the ESP and an extra 100mA (or so) for the relay.