ESP8266 Community Forum

- Tue Jan 02, 2018 11:58 am #72831 I bought 10 of these ESP-01 Relay boards.
Here are nicer board pics

It appears that the relay board does not have the required pullup resistors/jumpers to make the ESP-01 boot from flash. Also, before flashing them via the Arduino IDE, they boot up with a FaryLink SSID which I can connect to and get an IP address from with my phone or computer but a port scan doesn't show any open ports from 1-1024. I have been able to flash them via the Arduino IDE and my modified ESP-01 programmer but again, when I place the ESP-01 into the relay board it doesn't boot. The 3.3V regulator seems to be working as the ESP-01's power LED lights.

From my testing, I believe that GPIO 0 is supposed to trigger the relay through a transistor with a HIGH signal. Now if GPIO 0 needs to be HIGH to boot is that also going to trigger the relay?

So besides pulling GPIO 0 HIGH, does RESET & GPIO 2 need a pullup or just leave them floating?

- Tue Jan 09, 2018 5:47 pm #73022 I have several of these relay boards. They work, but they need to be modified.

You need a 10K pullup to Vcc on GPIO0. Also, I tied GPIO2 and CH_EN to Vcc.

Now when GPIO0 goes HIGH, the MOSFET will conduct, closing the relay and turning on the indicator LED.

- Tue Jan 09, 2018 7:21 pm #73025 The ESP-xS series of modules have the required pull up and down resistors.

- Tue Jan 09, 2018 7:47 pm #73027

I have several of these relay boards. They work, but they need to be modified.

You need a 10K pullup to Vcc on GPIO0. Also, I tied GPIO2 and CH_EN to Vcc.

Now when GPIO0 goes HIGH, the MOSFET will conduct, closing the relay and turning on the indicator LED.

I used a jumper from Vcc to CH_EN and a 9-11K pull-up resistor for GPIO0. The ESP boots but the pull-up does not seem to trigger the relay.

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