There was a guy on here selling "The Hammer Feeding System". Google search will bring up their website.

I haven't owned one, but they seem to have good reviews.

I buy krivoman feeders that use the Hammer timers. Been using them for 8 yrs or so. You can set the timer to stay open all the time or however you want. I have mine set to open at 6 in the morning & close at 6 in the evening. The deer can eat all they want all day long. Coons etc don't clean me out at night.

I have fed protein free choice or in timed feeders since 1990. Feeding deer free choice can get expensive but it does not make them nocturnal. They are nocturnal due them not living on your place. They are having to travel to far to get to you feeder in the daylight mainly. Timed trough style feeders have their place and you can feed to your budget. I feed year round no matter what style feeder I use. Right now I have 4-600# All Season timed trough feeders in pens. From mid Jan. till late August I feed from 2-4 times per day and only feed at night. Deer, bucks especially, are much more comfortable feeding at night. This time of the year they have been pressured and will readily feed at night. In the heat of the summer it makes no sense to try to get a mature buck in a feed pen when it is still 100° at sundown. IME I have found that bucks feed most (free choice) from 11pm till 4am. I feed with my timed feeders from right at or just after dark. Then again after midnight and finally about 30 minutes to 45 minutes before daylight. By doing this I have found I mainly feed bucks and they are who I am targeting. Does still come in but not as often...some pens I never see a doe at a protein feeder. When Sept 1st hits I change my times for protein to 15 minutes after daylight in the mornings and then sundown in the evenings. I have no trouble seeing bucks when doing this. The longer you do the same routine the more bucks you raise on the feeder routine...the better your hunting gets. Especially in archery season. I still corn feed year round just not very much from late Feb till late August and mainly at dark or daylight. I then spin corn 4 times per day in hunting season and lots of it. So I have a feeder going off 3 times in the mornings and 3 times in the evenings all at different times at all locations. Protein is great for growing bucks but also great as an attractant. I do hunt my feeders but never shoot a deer inside a feeder pen. That is what a road feeder is for.