Improvement idea: Add configuration option (setting) for DisplayContrast

[Torfbold]

Hi,
as some people might be running the device in their bedrooms and are somewhat sensitive to flashing lights the updating display could cause some issues during sleep. Maybe it would be a nice feature to enable some "night times" ( best would be configurable) at when the display is turned off (and on again the next morning) . Looking into the code there should be the option to call the commands against the display - either turning it off completely or reducing contrast.

[MyOwn2C]

You can alap just unplug the display after configuring.

[Torfbold]

Agree on plugging out the display - but this leads to the log being basically unreadable:

₿ (73389942) i2c.master: s_i2c_synchronous_transaction(872): I2C transaction failed
₿ (73389952) i2c.master: i2c_master_transmit(1074): I2C transaction failed
₿ (73389962) i2c.master: I2C transaction unexpected nack detec

EDIT:
I just checked - if I plug it in again - the errors from log are gone - display keeps blank - probably until I reboot and it gets initalized again.
So that option is also fine - tyvm

[mutatrum]

Don't unplug or plug your display while the machine is powered on, that can easily break the display.

No display option will probably come in the future, there's already a screen timeout in the works: #525

[mutatrum]

This might be difficult, as the Bitaxe doesn't know what time it is. There are two options for that:

• Use the time given by the mining.notify message from the pool. This is block time, so not perfect, and it's in UTC, so without timezone information.
• Use NTP and query for the time.

Neither are really nice options.

[Torfbold]

Agree, if "night time" is no option, maybe an alternative is an API call to disable the display (something like the restart button from the menu on the left side). Additionally a contrast Parameter could be helpful to reduce brightness?!

[mutatrum]

I tested a bit, there is a contrast parameter. Unfortunately it's not built into the driver, so this would be custom code for this panel, which is a bit of a shame:

#define SSD1306_CMD_CONTRAST 0x81
ESP_ERROR_CHECK_WITHOUT_ABORT(esp_lcd_panel_io_tx_param(io_handle, SSD1306_CMD_CONTRAST, (uint8_t[]) { 0x00 }, 1));

On my display it changes contrast a bit, but not on the range you would expect. Setting it to 0 is about half, maybe one third brightness compared to 255. Apparently it's configured with a resistor on the display? See: https://forums.adafruit.com/viewtopic.php?p=573606#p573606

Some people mentioned not all SSD1306 displays support contrast setting, so YMMV.

[mutatrum]

I've opened an issue at esp to support contrast through their lcd drivers. espressif/esp-idf#15015

Maybe this ticket can be changed to add a screen contrast settings. That and #525, would that be ok to reduce the impact of the display at night?

[Torfbold]

@mutatrum : Thank you very much for all your efforts here! I really appreciate it.
Sure - that would be feasible I think.
How to proceed? Should I just update the original issue description?

[mutatrum]

No problem. Just renaming the title of this issue should be ok.