The fish feed system contains 4 parts:
* Food releaser (motor driven)
* On-Off Controller
* Signal conditioning circuit (or driver)
* Power supply

The food releaser - must contain the seedbox (filled with seeds/food) and a door (a way to release the food at a certain moment). There are many ways for doing that, for example by using a spiral stem (screw) inside the box or by using a spring(arch) door. The two methods are presented below.

In this example,we have used the second scheme. Of course there are many other ways to create the seed box, you only have to have imagination:)
The motor that drives the door must be a low-power one, to save the batteries energy.

On-Off Controller is the 'brain' of the system, it commands the motor to start or to stop, depending on external or internal events. An internal event is actually generated by a clock (timer) and an external event is generated manually, by a human agent. So the controller might be automatic or manual. For a manual remote-controller (using a GSM device) check this article . In this example, we have used the clock from an automatic controller (microcontroller ZelioLogic Smart Relay). The main idea is to have a 0V tension when there is no event and > 0V (typically 5V) when an event occurs.

Signal conditioning circuit is an electronic circuit or driver that stands between the command system (On-Off Controller) and the motor. It is not mandatory in all situations, but it helps to protect the two parts of the circuit or to obtaing the needed signal. An optical isolated circuit driver is presented here

The power supply must give enough power to run the main motor and also the circuit driver. It is recommended to use common batteries or rechargeable batteries to avoid energy failures.

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