| preset | HDMI switch | projector | A/V receiver |
|---|---|---|---|
| off | off | off | off |
| Chromecast (video) | 1, 2.1 | on | on, "Dolby II (Movie)" |
| Chromecast (audio) | 1, 2.1 | off | on, "Ext. Stereo" |
| Switch | 3, 2.1 | on | on, "Dolby II (Game)" |
| PS4 | 4, 5.1 | on | on, "Direct Surround" |
For off/on signals (which are the same signal), the pHAT should also listen for these and keep track of the device's state, even if it did not issue the signal. Likewise, the A/V receiver cycles through a series of surround sound settings.
There should be some quick way to recalibrate the rPI's record of the devices' states when they get out of sync (e.g. the device receives a signal that the pHAT misses, or a device's hardware buttons are used, or there is a power outage).