The increasing winter power bills may have been an incentive.
Thought I would share this work in progress,
Here is the current hardware I am using
- 1x WeMos D1 Mini Lite $4.00 NZD
- 1x SCT-013-00 CT Sensor $6.50 NZD
- 1x ADS1015 Module$3.49 NZD
- 2x 470k Resistor $cents
- 1x 22ohm Resistor $cents
- 1x 10uf Capacitor $cents
Total cost: $13.99 & some cents
While testing, I just have the CT sensor clipped over an exposed neutral wire of a socket board with a 2000W heater plugged in.
(The meter is just for checking the readings are correct)
I may eventually change to a different bare-bones ESP8266 / ESP8285 board that uses less power when sleeping, but the D1 is really easy to develop with for now.
I may eventually change to a different bare-bones ESP8266 / ESP8285 board that uses less power when sleeping, but the D1 is really easy to develop with for now.
The code running on the D1 currently reads the power every 30 seconds.
It stores 10x readings and then connects and send them via WiFi.
This should help the board last much longer on batteries than if it sent the reading every time.
Here is a snippet of the D1 code:
My next step was to find a FREE service online where the data could be sent.
There are plenty of these but most don't store historical data for long.
I also need the ability to run a script to process the incoming data to work out the actual timestamp for each reading.
The solution was Google Sheets & Google Scripts!
Here is a snippet of the Google Scripts code (Javascript) that processes the incoming readings.
It gets the current timestamp. It then basically works backwards to find the time that the first of the readings would have been done at. Then increments going forward as it adds the data to the spreadsheet.
And here is the populated spreadsheet
My next step is to write a Google Script that runs at 11:45pm each night and calculates my highest usage hour.
It will then update my Electric Kiwi Free Hour of Power to it.I decided to do the most complicated stand-alone setup first so it should be an off-the-shelf solution for other Electric Kiwi customers. It will be easy to work backwards from this to integrate it with other things (smart home setups etc)
Update 18/06/2018
Today I am working on switching all the communication between D1 and server to use JSON data.
Also, all config will be stored on the server and the D1 will fetch / update it's config when it pushes up it's readings.This allows for one lot of D1 code and the user being able to adjust it's config on-the-fly via changing the online config.
You can see the current base config here:
The new code returns it's config values to the D1 every-time it receives readings.
The D1 will then update it's settings accordingly.I also had a good idea on how to reduce the power used by having the D1 sleep for the time periods where you can't have a free power hour (7am - 9am, & 4pm - 9pm).
You could also add more time periods you know won't be the highest eg. 12am - 5am.That's at least 7 hours a day where the D1 could be sleeping and saving battery!
Here is the latest process code:
You can see that if the last reading's time is within a sleep time period, it works out how long it can sleep in seconds and sends that back to the D1. The D1 will then sleep for that amount of time.
Also, it's now storing all the times in local date time (instead of unix timestamp).
Update 19/06/2018
Added ADS1015 to part lists.
The ESP8622 built-in ADC is not very accurate and crashes often when trying to read over X readings for second. The ADS1015 should easily handle the task and give more accurate readings.
The ESP8622 built-in ADC is not very accurate and crashes often when trying to read over X readings for second. The ADS1015 should easily handle the task and give more accurate readings.