I’ve had numerous people ask me about adding a second display, i.e. the main screen would be in the bedroom and another one would be in the living room. I like this idea so decided to check into it.
I re-configured a screens to act as a remote touch screen. Unlike the main screen, the remote screen doesn’t need the access point or MQTT broker software installed.
As a test, I have a newly configured remote touch screen sitting in my house (photo below). It automatically connected to the wifi access point inside my Southwind motorhome that’s about 40 ft away. It works like a champ. What I’m seeing on this display is exactly the same data that I’d see on the screen inside the motorhome.
The remote screen runs the exact same operator interface software as the main screen so the operators screens are identical.
Technical – How it works.
The main reason for using the MQTT broker system is to allow stuff like this to happen. Anyone with any software skills could create their own operator screens. SInce we already have one created for the main screen, we use that same software for the remote screen.
The main screen is a micro computer (Rpi3) with operator touchscreen, wifi access point, and the system MQTT broker installed. The main screen software communicates directly to the MQTT broker, because its on the same computer.
The remote screen needs to get its information from the main screen computers MQTT broker. It does this by connecting to the main screen via wifi and then communicates with the main screens MQTT broker.. All the info that is displayed on the main screen is also displayed on the remote.
Both screens share common information that comes from the control module(s) via the MQTT broker. These are such things as mode, set points, time display, amps, DC volts, etc.
EXAMPLE: If I change the mode or a set point on the remote screen, I’ll see this change also displayed on the main screen.
Although most control settings and status are common and shared via the MQTT broker, each screen does have some unique settings that are particular to that screen only and don’t go through the MQTT broker, These items are things like day / night dim settings, display units (C or F), alarm clock, schedule settings, and what screen tabs to display.
I haven’t released this yet, but if you’re interested, send me a note on the CONTACT page. I’m thinking it will probably be in the $300-$325