Easy configuration without reflashing

[ThomasFarstrike]

The current method to change the configuration is to use the webinstaller to provide the configuration values and reflash the firmware.

This is a bit tedious because it requires the user to connect the device to their laptop, open the webinstaller, fill out the configuration form fields, and install the configured software.

So we would like an easy method of configuring the device:

• without needing a laptop (a smartphone should suffice)
• without needing to fill out all the (already configured, existing) configuration values
• without needing a USB cable
• without needing a USB-to-serial converter

The easiest (and also pretty standard) way to do this would be that if the device has a "configuration mode".

In this mode:

• the device creates a wireless hotspot (access point) which the user can connect to with their laptop or smartphone
• it shows a custom screen to indicate it is in configuration mode, the URL that should be opened (http://192.168.4.1/), a QR code of the same URL etc
• upon browsing to the URL, the user sees a configuration form, similar to the webinstaller but with already-configured fields pre-filled so they don't have to redo them
• the piggy shuts down after some time to conserve power

Configuration mode is triggered if:

• the wifi connection (SSID) is not configured
• the wifi connection fails
• the user long-presses the General Purpose button on the device for 3 seconds

Having this feature implemented would also allow us to pre-install the software in the factory, without configuration values. When the user then receives and powers up their device, it goes into configuration mode, allowing the user to configure it.