Purpose of this project came about cause of
couple cheep Chinese webcams that I have in one garage and one
looking at the driveway randomly hanging and not responding. Its
very annoying of not being able to see whats happening when I'm
at work and cant get to those cameras so I figured I'll build a
web controlled couple relays and either punch a port through the
router or get to home LAN via VPN and reboot those devices and
the simplest way would be to use NodeMCU chip.
Other part as the device would be mostly just sitting there and
waiting for connections, and as I'm working in garage quite
often or like to find temperature why not add couple temperature
sensors and monitor temperature inside the garage and in front
of the house.
For the garage decided to use DHT sensor as it gives temperature
and humidity, I did not cared to much so I used DHT11 which has
+/-2' variance, not a great issue but if I decide I can switch
it for DHT22 which has greater accuracy. With outside
temperature I decided to use LM35 sensor as I wanted to use the
analog port on the NodeMCU and have extra pins free maybe for
something else later on. One other thing I did add to this
project was light sensor as I had been told I sometimes I leave
the lights on not that I can shut it off but at least it can
tell me that they are on. Simple LDR is used for that which
leaves 2 digital pins free after connecting display over I2C
port on 0.9 version of the NodeMCU. 1.0 version has couple extra
pins not that they are necessary at the moment. One thing
in the future maybe I'll add routine to track time of how long
the lights are on and watch for movement activity on PIR sensor
and send me email status.
So far main code is done and working. Next
thing to make is PCB with provision for 0.9 and 1.0 chips and
maybe a base Node chip that I can solder onto the board.
Next update to the code I like to add large display clock and
have it automatically sync with NTP server on the internet as it
would be nice to have clock in garage and not worry that it gets
reset cause of power failure and WiFi manager so I would not
have to hard code WiFi credentials into the code which is most
annoying. But for now current code is <here> will all necessary
libraries <here>. You will have to
remove the .txt extension form the code file and extract the
library archive and install it into Arduino IDE
Wanted to make the controller as simple as could
be and to minimize on components. With the heart of the
controller being NodeMCU which has all the necessary circuitry
for CPU WiFi circuit and programmer interface. Additional
components are hand full of passive parts and depending on drive
it can vary from power transistors if so to relays. In our case
we are using relays as the contacts are isolated from control
circuit. We did add additional status LED to have visual
indication when looking at the controller. Additional DHT11 and
LM35 sensors provide temperature sensing and biased Light
Dependant Resistor (LDR) resistor
provides light sensing.
Web interface / Software
Tried to make the web interface as simple and as possible and
had divided into control and sensor status display.
Load status column is dynamic where the load channel button
turns yellow when energized and goes gray when turned off. The
controller is setup currently as true positive meaning that the
output pin on controller is positive when energized.
Column On and Off are controlling state of the output. The code
is written in a way that for all both buttons are showing all
the time where as for individual load control channel On and Off
buttons are alternatively shown.
Thought was that there is no need to show the On button if
the load is On. This can be changed in each table row output
control. The IF statement controls how the load is shaded and
also selects if On or Off buttons are shown. If there is no need
to control shade of the load button cell nor controlling which
button is shown by removing/ commenting the IF directive and
un-commenting the 3 lines below it.
At the moment the display refreshes each time the
load control button is clicked on or refreshed once every 15
seconds automatically. When connecting to the device, actual
state of the output will be shown due to that there are status
flags for each output and are used within the HTML code section.