So I bought this ESP32-WROOM-32E with an integrated 8-relay module.
When it arrived I noticed it does not have an USB port…
Is it possible to programme any ESP Home code in it?
Is it worth the trouble? Or shall I put in the box of things I’m hoping to be useful later, but most likely the won’t?
You need a USB-TTL UART Serial Adapter and a handful of jumper wires… There are many different variations available.
No one can answer that but you. 
If you plan on doing more DIY projects in the future it’s probably worth a few dollars to get an adapter.
1 Like
I read a while back you could use a nodemcu-like ESP as a serial adapter. Never tested it myself, though.
https://www.reddit.com/r/esp8266/comments/d1o6pc/using_nodemcu_d1_mini_as_usbtoserial_converter/
1 Like
Thank you very much for the info! Will check this out.
Sounds promising. Thank you very much. Will check it out.
So, I’m trying this path with a D1 Mini (ESP8266).
The instructions are:
Connect EN to GND on the NodeMCU to disable ESP8266 chip TX/RX connection is not crossed as opposed to using TTL breakout. You can use NodeMCU's D3 pin as DTR
So connecting to Arduino Pro Mini for example:
NodeMCU → Pro Mini
GND → GND
3.3V → 3.3V
TX → TX
RX → RX
D3->DTR
Any idea what the heck is the “EN” in the D1 Mini?
Any idea what the heck is the "DTR " in the ESP32?
If you don’t need it gift it 
to someone but don’t waste resources by trashing 
it just because you don’t have a use for it 
EN pin is enable pin.
I’m not sure that is on the breakout board of the D1 mini.
Perhaps you need to solder it directly on to the ESP-chip.
I suggest you get a proper TTL flasher instead.
It will be so much easier and you will be using it some time in the future anyways.
1 Like
Could you point me to a nice TTL flasher I can grab for example from Aliexpress?
Thanks sir.
Now i just need to know the meaning of "DTR " in the ESP32.
I think any TTL flasher will work.
Just make sure it has both 3.3 and 5 volt modes.
And make sure you use a multimeter to test the voltage before using it
1 Like
You can ignore that. Just connect the Voltage, Ground, TX, and RX pins, and keep GPIO0 grounded before you turn on the ESP.
1 Like
Dully noted. Will do.
Sure thing!
Reporting on this path.
I did connected the D1 Mini with the ESP32 relay board, like so:
I used web.ESPHome.io in Chrome to install this code, which I adapted adapted from here:
esphome:
name: esp32-8xrelay
friendly_name: ESP32_8xRelay
esp32:
board: esp32dev
framework:
type: arduino
# Enable logging
logger:
# Enable Home Assistant API
api:
encryption:
key: "..................."
ota:
password: "................"
wifi:
ssid: !secret wifi_ssid
password: !secret wifi_password
# Enable fallback hotspot (captive portal) in case wifi connection fails
ap:
ssid: "Esp32-8Xrelay Fallback Hotspot"
password: "..........."
captive_portal:
# Status LED
light:
- platform: status_led
name: "RelayBoard Led"
restore_mode: ALWAYS_ON
pin:
number: GPIO23
inverted: true
# 8 relay outputs, exposed as switches in Home Assistant
switch:
- platform: gpio
pin: GPIO32
name: Relay1
id: relay1
- platform: gpio
pin: GPIO33
name: Relay2
id: relay2
- platform: gpio
pin: GPIO25
name: Relay3
id: relay3
- platform: gpio
pin: GPIO26
name: Relay4
id: relay4
- platform: gpio
pin: GPIO27
name: Relay5
id: relay5
- platform: gpio
pin: GPIO14
name: Relay6
id: relay6
- platform: gpio
pin: GPIO12
name: Relay7
id: relay7
- platform: gpio
pin: GPIO13
name: Relay8
id: relay8
And the result was this: video5942618425506402734
Repeated, but this time, following the process I normally go when programming ESP32’s - I pressed the IOO button (equivalent to “boot” I think) while booting and when beggining the code upload in ESPHome.
Result was the same.
Any ideas?
I don’t think the board actually got in to flash mode.
I have a hard time thinking that the flash mode of an ESP would light up LEDs like Knight rider.
That seems to be some programmed code flashing the LEDs.
1 Like
We’re thinking pretty much the same here. Today I will give a go to a USB to Serial converter, maybe this way Im more sucessful.
That’s an LC Technologies 8-relay ESP32 board. I’ve used two of them with ESP8266 and they flash fine, once you install the pin headers beside the microprocessor and connect a USB-to-TTL serial cable. I’d imagine the ESP32 version is very similar. Identify the TXD and RXD and GND pins, and you should be good. It appears you connect together the IO0 and GND pins to flash it.
From their web page, the ‘Burn Interface’ is the pin header at the ‘top’ of the ESP32:
1 Like