Hichi-mon

Monitoring and logging power consumption, as read from a smartmeter via a Hichi unit, using an esp32 board (optionally) fitted with an ssd1306 display - without the need for a home automation server installation. :)

How To Use

Copy config.h.default to config.h and edit config.h according to your needs:

• WiFi credentials must be adjusted here;
• Hichi network address may also need adjusting;
• follow the directions in the DROPBOX section to add logging;
• check if anything else needs adjusting. Then compile Hichi-mon.ino and install it on your esp32 to be used as a monitor.

If all goes well, you should see data from your Hichi unit displayed on the Hichi-mon unit.

Functionality

Hichi-mon fetches the current power reading from your Hichi unit via HTTP every second, for display and logging.

Display Contents

A rolling chart of the most recent power consumption values is displayed. Depending on whether FULL_DAY_DISPLAY is #defined in config.h, it will either contain a plot for the most recent 24 hours (this will take 24 hours to complete before starting to roll) or for the most recent ten minutes (which provides more detail, but is more fleeting).

Please note that for the graph, the power readings are averaged over twelve minutes (for a 24 hours display), or over five seconds (for a ten minutes display).

To the left of the chart, three values are printed: the lowest power reading displayed in the chart, the most recent power reading obtained from the Hichi unit, and the highest power reading displayed in the chart.

Example for a ten minutes configuration:

Example for a 24 hours configuration:

(In case you're wondering about those negative power readings: I have a small solar power station installed.)

Screenshots via HTTP

You should also be able to display Hichi-mon screen contents (even without an ssd1306 display attached) on any web browser in your network by loading http://<your-Hichi-mon-address>/.

If you want your browser to display those tiny images enlarged upon loading, you can use Hichi-mon.html instead of loading the image from your Hichi-mon unit directly. (You may have to adjust the address of your Hichi-mon unit in the *.html for that.)

Logging to a Dropbox Account

Periodic saving of log files and screenshots (see above) to a Dropbox account can be enabled in config.h. For this function to work, read/write access permission must be granted to Hichi-mon; to achieve this, load Get_Dropbox_token_for_Hichi-mon.html in your web browser and follow the instructions.

The log files saved will be named yyyy-mm-dd_hh.csv, with the files' basename representing the current day and hour. They will be updated as specified in config.h, and contain text lines in the form of hh:mm:ss W, providing power readings for the times given, e.g. 23:45:12 98 for a power demand of 98 Watts at about a quarter before midnight.

To limit log data loss when restarting your Hichi-mon unit, existing *.csv files will be read and continued when switching to a new yyyy-mm-dd_hh. Performing an OTA Update (see below) will force *.csv writing immediately before the device's reset and reload the data from the file and continue it after the reset.

Screenshots are saved in Windows bitmap format, and are always overwritten: Only hichi-mon.bmp is kept as the most recent screenshot.

Data Log Viewing

Just load the *.csv log files into your favorite spreadsheet application (e.g. Excel, ...) and let it give you a plot of the power consumption!

...or, if you're on a Unix system and have feedgnuplot (and gnuplot, perl, etc.) installed, you can try out hichi-mon.sh, and see if it fits your needs.

When called without parameters, it tries to read *.csv log files for the current day from your Dropbox account (see above), and provides you with an interactive graphical display of the data contained in the files. If you want to look at older data, provide the desired date in a yyyy-mm-dd format as a parameter, e.g. hichi-mon.sh 2023-07-17.

Example output:

(If you have no power generator (e.g. PhotoVoltaics) in your house, and therefore no negative power readings, the "Energy (paid for)" curve will equal the "Energy (net demand)" curve, and "Energy (PV excess)" will be a flat line. Just adjust hichi-mon.sh according to your needs.)

OTA Update

By loading http://<your-Hichi-mon-address>:8080/ in your web browser, you can update you Hichi-mon's software "over the air" (OTA). There you can upload a file created via Sketch -> Export compiled binary file... in the Arduino IDE. (Of course this works only with an esp32 already running OTA enabled software, i.e. the first time you have to load the Hichi-mon software onto your esp32 via USB.)

Notes

Hichi-mon has been derived from my BSBmonCR.

Coding

• In most places, screen coordinates are hard coded for a 128*64 display, not calculated to fit a screen with possibly differing dimensions.
• Error handling in some cases may not be considered "production ready".
• Coding style is not always consistent (e.g. usage of String vs. char*).
• In serving screenshots, HTTP handling is pragmatic, not polite.
• Code comments are limited to what I personally have found useful (e.g. no comment blocks introducing functions, ...).

Known Issues

• (none)