This is really easy to build project which uses couple external components, Arduino and an old photo frame. All you need is to store 720 pictures with actual time words – for each minute in 12- hour cycle and then let the circuit to hit next button every minute.
First of all in order to hit next button you don’t have to build some kind of mechanical actuator – simple optocoupler will work fine. And probably the hardest thing is to think of generating 720 images with different words on it. No problem with that – a processing script can do this for you – just select right parameters and run script. After images are generated – upload to photo frame memory and start a clock. Someone wants to change frames every second – that’s only a 43200 frames to generate 🙂