I had a unique problem in my rural community and needed to find a sound solution to address it. A previous attempt using a raspberry pi running windows 10 Iot with a touchscreen was not very successful. This would work for a few days and the system would crash and sometimes difficult to start. I needed a new solution, but before I present the new solution let me describe the problem I was trying to address.
Schedule - settings
MQTT- setting up
What to watch for - potential problems to watch for, memory restriction etc.
Boards - These boards have been tested to work.
GPIO pins - Default GPIO pins
Realy Interfacing - Interfacing to relays
Yes a drone took that picture!
The one thing I miss is the image slide show for the 1000+ photos stored on the sd-card. Original implementation was on .NET windows iot and the code base can be found here for the web service. and here for the Http Server on github.
Some video clips on this are on YouTube here
These 10 solar panels each rated at 300 watts generate a total of 3000 watts, ie about 3KW on a full sun. In my area I do get very good sunshine from about 8:00 in the morning to about 4:00 in the afternoon. On the days of good sunshine you actually get a little more that that amount of energy. You cannot store all that hence you need to find ways to use the power realtime once the battery bank is full.
At night a wind turbine unreliably adds some energy to the battery bank whenever a gust of wind breezes by.
Part of the solar energy is stored in the battery bank. Once the batteries are fully charged excess solar energy could go directly to appliances like cook tops and refrigerators without the need to use the battery bank. Power will go from solar panels to battery charge controllers straight to the inverters. So for example I do my clothes ironing around lunch time or as soon as the batteries are full.
Well without an electrical engineering degree you can only do so much but the wiring is safe. Electrical grounding and lightning protection was my number one.
At night time there is no more electricity coming from the solar panels and the wind turbine is unreliable. I rely on whatever has been stored in the batteries if they are still good. For small power usage the battery bank can handle the power needs. In order to have long life for the batteries we need to make sure that heavy appliances are not used after hours.
I need a network of systems that are each service a particular need. Conserving of electricity is primary. Power must be shared among all appliances and a way to do load shedding if necessary. In Summer the water table goes below safe level and sometimes dangerously low. The system must protect the water pump from running dry.
Water Pump can only run from 8:00AM to 4:00PM.
Pump to run only run for 3-5 minutes every 15 to 30 minutes if the water tank is empty.
The Fridge must run from 8:00AM to 6:00PM daily.
1. Bedroom lights to turn on at 7:00PM, turn off at 10:30PM
2. Living Room lights turn on 6:00AM, turn off: 10:00PM.
1. Bedroom lights: after 10:30 PM lights must randomly turn on/off for configurable duration until
4:30AM when they go off completely.
2. Living Room lights: after 10:00 PM lights must randomly turn on/off for configurable duration
until 5:00AM when they go off completely.
It is important to safely operate the pump against the said potential problems, the pump cannot run dry.
Electricity is scarce and no water pumping or fridge operation at night unless manual override by user.
The control systems must be isolated from each other and be able to recover schedules as soon as possible
is an event of a crash.
The control systems must get their time from the internet but also allow for manual time setting in the
event internet time is not available.
Have a central place to manage these systems.
Each system needed to control one device or a few at a minimum. I looked into the esp8266 micro-controller and it was the most promising. However there is some basic work that is needed to prepare configure the chip, wifi, file system, webserver interface etc before you can put your system on it.
I did not want to re-invent the wheel, so I researched and found that my best option to build on was work done by [rjwats] (https://github.com/rjwats/esp8266-react).
A basic scheduler for ESP8266 and ESP32 based on rjwats.
Advantages of the rjwats framework high-level
1. ReactJS front end easy to customize UI
2. Wifi ready
3. Access Point
3. OTA and manual updates
4. MQTT enabled
5. Security features
6. Network Time
7. Manual Time settings
You get all the above right out of the box, kudos to rjwats. On top of the above I added my system functions with configuration via an easy to use UI.
1. Status
2. Automation
Make sure you are familiar with building the project by going to rjwats for more documentation. It might be helpful to just go through the exercise and build that project on its own before you clone my react scheduler.
I try to keep updating my master branch from rjwats to take advantage of any new updates that may be useful.
| Normal settings | Timespan settings |
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| Randomize and Hot-time | MQTT Settings |
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You will notice that as you add new features to the project you quickly run out of memory. To get around that the complete UI is deployed to a device that has more memory like the ESP32. This is then configured as the master device on the target device. The other device will only deploy the backend code which implements the apis but not the UI. This saves memory and cpu cycles on the smaller device. To remotely configure the chip you need to point to the master device, i.e the device that has the whole UI. The following URL will configure device on ip 192.168.0.104 from the UI on device ip 192.168.0.172. Adding the remote device ip makes it possible to directly manage the device from homeassistant
http://192.168.0.172/p/a/1#?d=192.168.0.104&c=Esp-01%20Express%20B
With homeassistant integration the URL is created for you and you just need to click from the homeassistant screens under attributes.
This will allow you to do all the device configuration of the remote device from the device with more memory with the remote device doing the authentication if enabled.
When configuring a remote device, its ip address will show on the top that way you know you are configuring a remote device and not the local device.
This simple app allows user to control a switch through a simple schedule. It comes with default
settings that can be changed by user.
Channel Schedule is active only between the 'Start Time' and 'End Time' periods. Changes to the
schedule must be saved to take effect. The changes take effect after 5s from time changes are saved.
The schedule for the Channel is restarted with the new settings. The system also provides the device
time as well as the IPAddress of the device if connected to WIFI.
User defined channel name that shows on the screen, if one is not provided system defaults to factory
settings value.
Is a set of user selected options that determine the periods during which the connected device may be
controlled automatically.
When checked the schedule is active. Now the build version is available next to the checkbox text.
This is the hardware pin on the micro-controller user may connect a relay in order to control a device.
Solid State Relays (SSR) may be connected directly to the pin without the need for buffering transistors.
When checked disabled 'Randomize', the switch is activated only during the time period from 'Start Time'
to 'End Time'.
When checked enables 'Hot Time' feature, the switch is on/off randomly within the 'Run Every' and 'Off After'
limits. Disabled when 'TimeSpan' is active.
When checked enables minimum runtime is at least 'Off After' value enabled when randomize is active
Turns on the switch repeatedly at the selected time frequency. If 'Enable TimeSpan' is checked the option
is disabled and is ignored. If 'Randomize' option is enabled the switch can turn on after a random delay
up to 'Run Every' minus 'Off After' duration. This is useful to simulate person turning lights on/off at
night in bedrooms.
Turns off the switch at the end of this time period automatically after switch is activated by the
'Run Every' event. If 'Enable TimeSpan' is checked the option is disabled and is ignored.
If 'Randomize' option is enabled the switch can turn off after a random delay up to 'Off After' duration.
The start time when the schedule is active. If the start time is greater than the end time then
schedule ends the following day.
The duration that the switch is on before randomize feature takes over. This is useful when you want the light to remain on for say 3 hours after the schedule begins then after that 3 hour configurable duration it enters into random mode where randomly the light turns on and off throughout the night to simulate a person waking up in the middle of the night to operate the lights. An unwanted guest might conclude people are still awake and skip his plans for the day.
The end time when the schedule is active.
The IP address of the microcontroller that will serve the UI for low memory devices.
Homeassistant integration comes for free, check out resource for Homeassistant here
When properly integrated homeassistant will show the schedule attributes from homeassistant which the device registers with the MQTT auto-discovery feature of homeassistant without any custom configuration on homeassistant. This out of the box integration feature with homeassistant makes it possible to just add new devices and managing them from homeassistant. The IP address of the devices is sent to homeassistant as part of config payload data.
Reboot on the first of every month when Enabled allows to automatically reboot the device one hour after midnight. This is controlled during compile time and must be set in platform.ini.
Homeassistant can be accessed remotely for free if you install Tailscape VPN client and the Homeassistant Add-On
You will need to signup for an account and install the addon feature to homeassistant. After installing the add-on and configuring with the key you will need to install the VPN client on your device and that's it.
Like every project, it comes with challenges and lots of frustration. But they say no pain no gain,
besides solving a hard problem brings a lot of satisfaction in the end. Below are some of gotchas
to watch for.
The most important thing is to get your environ properly setup for esp, VSCode makes it easier to work
on the project and there are tons of articles to get you up to speed.
Do not have a long running process in your loop, the system watch-dog will yank the carpet underneath
your code without notice and will be very hard to debug. If you see your chip resetting often that may
be the case.
If successfully deployed to the microcontroller the onboard led will blink fast while looking for an access point and then when it gets
wifi connection it will blink slow. If you see the led flash again after it has gotten wifi it indicates
the system crashed and restarted.
The project has four independent channels that can turn on a switch per the schedule defined. However only
the ESP32 can load all the four channels on the chip and work well. ESP8266 can only handle one channel
especially if you want to be able to override the system defaults by using the React UI.
The Esp-01 cannot deploy the UI.
You can choose which channels to install by uncommenting the corresponding CHANNEL in the platform.ini file. This is particularly useful on low memory devices as they can only handle one schedule. You will need to disable
;-D PROGMEM_WWW
in the platform.ini in order to fit the binary.
This board supports all the four channels. You can use this as the master device to contain the UI to configure the devices with less resources. It can also be simultaneously used for its own schedules or you can disable them and then it simply acts as a "broker" for the UI of other devices.
esp32
This board supports all the four channels and comes with four onboard relays.
esp 32 lilygo relay board
esp8266
### sinilink board
This board supports one channel with an onboard relay. You can do OTA but need to disable PROGMEM_WWW and similar steps for esp-01 described below.
esp8266 sinilink
You will need to make sure you select right device in platform.ini, disable PROGMEM_WWW
and do not upload the react image, this device can only support one scheduler channel and will not support OTA as there is limited memory on the device. This is a cheap device that is abundant and good enough for controlling as simple switch.
esp-01
The UI supports changing IO pin used for turing on the relay. This is important for different devices have different pins for IO.
In order to control power to lights or whatever you intend to use the esp device to control, you will need to connect a relay to the control GPIO pin of the esp device and the relay connected to the AC power supply to then connect to the device under control.
The output of the esp module at the control pin is under 5 volts. You can connect directly to buffered relay modules but my preferred method is to use Solid State Relays (SSR). These are reliable and offer good decoupling from the esp device and protect it. These are now cheap and some most take control input voltage from 3V to 32VDC. The biggest advantage of SSR over conventional relays is their low price and maximum load they can control as well as the bigger voltage they can control. They also do not suffer from contact damage over time which happens with conventional relays as they switch on/off.
SSR-40DA
channel one GPIO 21
channel two GPIO 19
channel three GPIO 18
channel four GPIO 5
channel one GPIO 5
channel two GPIO 12
channel three GPIO 13
channel four GPIO 14
channel two GPIO 4
channel one GPIO 0
The system will not fit in low memory devices so you need to disable certain features, please refer to [rjwats] (https://github.com/rjwats/esp8266-react) for details.
In the platform.ini turn off
; Uncomment PROGMEM_WWW to enable the storage of the WWW data in PROGMEM
;-D PROGMEM_WWW
Only ESP32 with at least 4MB will support all the four scheduler channels including PROGMEM_WWW support.
All others devices will less memory you can only support one channel and have to disable PROGMEM_WWW
Additional device documentation can be found below if yo want to try different devices.
https://docs.platformio.org/en/latest/boards/index.html#espressif-32
https://docs.platformio.org/en/latest/boards/index.html#espressif-8266
https://docs.platformio.org/en/latest/boards/index.html#boards