How to time a little door so it opens at a certain time? (no need to close)?

I want to build an automatic cricket feeder for my lizard (bearded dragon) because I have to stay home at her eating times and sometimes I want or need to go out.

* Ideally I would like to build a small "cabinet" with 1-3 drawers and somehow make the doors open at 11am, 4pm and 9pm,
* If this is too hard one door will do but I would need to reprogram it constantly. (crickets would be inside and they would get out as soon as the door opens)
* I already have a timer that I can plug and program to 23 different times so I was thinking on using that (or not), It could be something that when on opens or keeps the door open, and I can keep it off the rest of the day with the timer, I just don't know how to do this and how to do something that won't burn after a minute on because that's the minimum time the timer works.
* It doesn't need to close back (and that is safer too)
* It can't be light activated because some lights are on at all times and another has a timer and goes on for 20 minutes every hour.
*It needs to be small because the terrarium is 18inchX18X18 and I don't want to take a lot of room

Thank you so very much!!

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frollard6 years ago
There are literally thousands of ways to go about this...

As Rube Goldberg as iceng's suggestion; a mechanical timer would do the job quite well.

Rick has a good feeder, and since it moves very slowly won't harm the crickets.

I like the idea of the trapdoors on the bottom -- a compartmental box with lids on the top and bottom that you can put a few in each compartment, using a slow gear motor or timed motor, you could slowly retract a rod from underneath all the doors to expose them one at a time.

A micro-controller solution is overkill but is a great project where custom timers are important. It's a great educational project.

Remember, per the zero'th law, if you make it you have to post it!!!
iceng frollard6 years ago
Thank you for the compliment,  I have always really enjoyed Rube Goldberg.
His style must be rubbing on to me :-D

solipsism6 years ago
get a real clock and put a piece of paper on the hour hand. embed it into a holder with 3 LEDs at the hours you want opposite a light sensor, when the hour hand blocks the light the electromagnet holding the door closed turns off and the crickets drop out.

mameloski (author)  solipsism6 years ago
Thank you very much for your answer, but I don't have an electromagnet holding the door, I don't even have the door... =(

That is what I want to know how to make, now I know I need to figure out how to have an electromagnet holding the door-to-be closed.

thank you!
iceng mameloski6 years ago
Friction or a snap lock.
rickharris6 years ago
Does you monster NEED to be fed 3 times a day?

However in industry something like this might be used.

The vanes revolve slowly releasing the food periodically depending on how fast they revolve.
iceng6 years ago
Is an alarm clock, a string, a cork and a tube tooo much for you.

Wind the alarm to pull a cork out of a cricket tube when the mechanical alarm
rings and winds the string on the key pulling the cork out.

It could pull a drawer too.

solipsism6 years ago
alternatively just buy 3 xmas light timers they are cheap, and have them turn ON to open the doors whenever.