Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)
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By liderbug
#73958 I stopped being sensitive a long time ago ... Turns out I hadn't researched enough. This relay board uses a STC15F104 or a STC16F104 chip as the control voltage to the base of the relay driver transistor. And to talk to the STC chip you send a set of 4 hex chars via TX. Why Serial.write instead of GPIO0/2 - because :roll: Reading up on the STC chip I have to think that there are more codes that are avail (wag) relSTAT, relXYZ??? But then again.

Code: Select all//Hex command to send to serial for close relay
  byte relON[]  = {0xA0, 0x01, 0x01, 0xA2};
//Hex command to send to serial for open relay
  byte relOFF[] = {0xA0, 0x01, 0x00, 0xA1};
...
Serial.begin (9600);
...  web/curl/php http://boardIP/on  or /off
if (req.indexOf ("/on") != -1)
  {
    Serial.write (relON, sizeof(relON));
  } else {
    if (req.indexOf ("/off") != -1)
      Serial.write (relOFF, sizeof(relOFF));
  }