TL;DR: I need to portion-feed my cat as he loves food too much. I made a feeding machine that is mounted out of reach, which means the kibble falls down and scatters on the floor, where he has to go around gathering it. Is this OK for a cat, or is not having his food in a bowl stressful?
Last Update: See update 3 below for why I'm not using this anymore.
Longer story: When we got our cat from the shelter he was 8 kilos (17.6 pounds) so we feed him a fixed amount of kibble a day (prescribed by our vet) trying to get it down (which works, he's now around 6 kilos).
We used to feed him about three times a day: 1/3 in the morning, 1/3 when we get home and 1/3 in the evening.
A problem we're having is how he likes to wake us extremely early (somewhere between 4 and 6 in the morning) because he is hungry. So I made a small feeding machine that will dispense his food, starting at half past 5 in the morning. It will dispense 1/4 of his food every 5 hours (so 5:30, 10:30, 15:30 and 20:30), as I read cats like to eat smaller portions during the day, instead of just one big one. (In the beginning it would give out smaller portions every hour, but I got the feeling this was too disruptive for him: by the time he settled down after eating and started taking a nap, he'd hear his new food falling and would start eating again.)
So this works great in the morning: when he hears the machine he jumps off the bed and goes downstairs to eat, without waking us. Afterwards he comes back to the end of the bed for some more sleep.
I can't put the machine on the ground because I'm sure with his determination to eat, he will destroy it. So at the moment it's mounted underneath one of the shelves we made for him to climb on and the kibble will just fall down and scatter and he has to go around that part of the room to get all of it. Do I have to find some way to get the kibble into a neat bowl, or is it OK for him to have to gather them? It does seem to help against eating too fast (because he has to search for some of them) and he seems happy enough (because food). But could this be stressful for him?
PS: He can get as much water as he wants. There is a bowl in nearly every room (away from his food so it doesn't fall in) that we change every day.
Before, I made a cardboard contraption with different holes and slots to put his food in so he has to search for it. I was thinking of making a larger, wooden one (like this from Purina) and put it underneath the machine so most of his food will fall in.
The 'machine' I made is an auger with a container on top for the kibble. A servo motor on the back turns the auger so kibble comes out. On the back is an ESP8266 board (basically a tiny computer with Wi-Fi) that connects to my home Wi-Fi so I can tell it to move and for how long. This is done automatically at set times, but I can also use my phone to trigger it. On the top you can see a wider part, which slides into a holder that is attached to the bottom of my shelf. The parts are 3D printed. It's a prototype so it still has some exposed wires in the back. This one is printed using PLA but I'm going to make another one out of a verified food-safe material.
Update 3: I didn't use this system for long. One reason was that my cat managed to get to the prototype and destroy it. But the main reason was that my cat was on edge all the time, completely focus on the sound of the servo and the kibble hitting the floor. It didn't seem healthy so we're back to feeding him ourselves again for now.