Using the ESP8266 to broadcast open/close MQTT events over WiFi
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This is another one of my additions to HomeAssistant, the amazing Smart Home/Home Automation software.
In order to track MQTT messages from this project, I added the following to my HomeAssistant configuration:
Andy Castille
binary_sensor:
- platform: mqtt
name: "Garage Door"
state_topic: "hass/garagedoor"
device_class: opening
payload_on: "1"
payload_off: "0"
@juan11perez has ported this project to Sonoff!
He has nicely documented the build in this PDF.
I just posted a new version of the code that also provides a server so that you can check the current status while it is running remotely:
$ telnet 192.168.2.8
Trying 192.168.2.8...
Connected to 192.168.2.8.
Escape character is '^]'.
mqtt_connected = 1
distance_cm = 102
door_open = 1
Connection closed by foreign host.
I had to modify the code to check the state twice and make sure the values match before sending an event because sometimes there are fluctuations in the sensor that would report it as open for a very small amount of time.
Because making that change involved taking the unit off the ceiling for USB programming, I also added Arduino OTA support so that future updates could be flashed over WiFi.
While waiting for my Amazon order to arrive, I designed a mount to contain the hardware and hold it to the ceiling:
| HC-SR04 | ESP8266 |
| Vcc | Vin |
| Trig | D1 |
| Echo | D2 |
| Gnd | GND |
All final hardware decisions are listed and Amazon-linked in the components section.
I started with my goal: to remotely check if the garage door is closed for peace-of-mind.
I decided that I didn't want to interfere in any way with the existing opener unit because I'd rather not break it trying to interface with it and I don't want to control it because that introduces a security risk. I decided to use a non-contact sensor to reduce wear on the door and/or sensor as well as any scratching noise or resistance to movement. This left one good option: an ultrasonic distance sensor. I can mount it near the bottom of the door opening or on the ceiling and check if it detects a door close in front of it.
I have an Arduino UNO, however, WiFi shields are expensive and I'd rather keep it available for tinkering. While researching WiFi-enabled microcontrollers, I stumbled across this article about the ESP8266. I found a nicer one for just under $10 on Amazon and now it's on its way.
Connect the sensor to the microcontroller board according to my setup so you don't have to remap pins in code. I used prebuilt F2F wires to make it easier on myself.
| Board | NodeMCU 1.0 (ESP-12E Module) if you're using the same board |
| CPU Frequency | 80 MHz |
| Flash Size | 4M (3M SPIFFS) |
| Upload Speed | 9600 |
Andy, this looks great. I'm curious though - if I did this with the ESP, rather than the Sonoff, would it be possible to add in a few more ultrasonic sensors? I'm thinking one fo the door position and two more for vehicle presence.
I don't have all the parts to try this yet, but I'm under the impression the Sonoff doesn't have enough inputs. The ESP should, but I know next to nothing about programming them. I assume I'd just have to find the part where you deal with the one and duplicate it a couple times and stick them on different digital pins on the ESP.
Does that sound sane?
Why would you need a fan for this thing? And it looks like you have designs for fan parts. Why not just get an off-the-shelf?
Pete Hoffswell
EasyIoT
IngGaro
I want to do a door sensor check like you, but with magnet and magnetic sensor. And ultrasonic sensor to check if car is inside or not, and maybe if it will work, check the sens of open/close during movement of my 2 doors.
All if possible with an ESP32 based board.