Hi Dave
Absolutely you can do this. 
Youāll get full access to all the button events, which includes the HVAC thermostat feature.
The feedback LEDs (even the Edge Lit lights are in development) can be controlled by openHAB2.
So for example ;
A Velbus button event can switch on a Non-Velbus device, via an openHAB2 rule. (I believe this is referred to as āProtocol Translationā)
openHAB2 will set the Feedback LEDs in accordance with the device status (assuming the rules are in place), so that if the device is switched off / on by another means, the feedback LED remains accurate.
Fairly simple rules can dictate the action dependant on other device statusā, so toggling a status, or incrementing (brightness / volume etc) until a button is released is fairly easy. (Incrementing / decrementing is easier with NodeRed flows)
Youāll also be able to use the Velbus button events that can be triggers by the timers inside each panel, which makes scheduling even easier, as you can adjust any of the 4 independent timers (in each Velbus Input device) from openHAB2.
- Wake1
- Bed1
- Wake2
- Bed2
Each timer can trigger events -
- Before, At or After each set time.
- Every day
- Weekdays
- Weekends
- Weekly
- Monthly
- Yearly
As for the Memo Text feature.
Yes, you can set Page 3 to display the Memo Text content. (Screensaver will always show the Memo Text)
So you could, use the 4 buttons on page 3 (for example) to manipulate the Memo Text content. (Max 64 characters)
(Reset / clear by sending a blank Memo Text command)
If you buy a number of Oled panels, Iāll throw in a VMB1RYNOS so that you can easily access some of the advanced features of Velbus glass panels that arenāt yet directly supported in openHAB2.
Youāre the first non-commercial person to go down this route, but youāll be glad to hear that there are a number of commercial installers who ONLY take this route.
Feel free to ask for any information or advice, Iām always willing to assist.
FYI,
As an example, Iāve got an Oled panel in my house which controls many DMX chases and other devices.
With a simple NodeRed flow, I can scroll through a series of scenes from a single button, or selection of buttons from different panels.
(With a Long press action set to switch off everything)
(I have similar DSL rules, but I find NodeRed flows easier to create & Debug)
Best wishes,
Stuart
MDAR Ltd
Reference links