A timer circuit design which could be used for turning the position of the eggs in an incubator between predetermined intervals of time was requested to me by one of the keen readers of this blog, Mr. Eugene.

The requested circuit has been exclusively designed by me and published here,

Circuit Specifications


Let's hear the whole episode:

I'm raising chickens for derby and I have hen that is laying eggs. For the hen to continue laying eggs, I need to incubate the eggs. I have researched incubator designs and parts and I have already assembled a simple one. I have a digital 220V ac thermostat and in order to protect it, it will only have to drive a 220V relay. This one already worked well.

Now I have an additional info that the eggs have to be rotated or moved upside down 3 times a day in order for the eggs to hatch well. I am planning to make a rows of eggs holder chained or built together driven by a motor such as electric fan swing motor. Its strong and moves very slowly and I think its quite enough. This 220v ac motor will be driven by a 6v dc relay. Now I need a relay driver circuit and a timer circuit that wil trigger the relay driver more or less every 8 hours for approximately 3 seconds only.

I may not have enough words to reach 300 but I think my intention is clear enough. But if the blog requires 300 words, I will try to extend my explanation.

Thank yo very much and I hope you can help me.

Eugene"

Designing an Incubator Egg Timer Circuit


The circuit of the proposed incubator egg timer and optimizer is given below:P1 should be adjusted for the long 8 hour duration and P2 for the short 3 seconds duration.

Circuit simulation:


Looking at the circuit diagram we can see that it consists of two identical IC 4060 stages which are coupled across each other for implementing the proposed actions.

The upper timer stage is intended for producing long time intervals and therefore its output is taken from pin #3, while the lower IC generates smaller time intervals and so its pin #15 is chosen as the output.

When power is switched ON the following things happen with the circuit:

The 0.1uF capacitor resets the upper IC so that it can start counting, during this period its pin #3 is at logic low which keeps the relay driver stage switched OFF, also the lower BC547 is kept disabled, which keeps pin #12 of the lower IC at high logic which in turn renders the lower IC inactive.

After the predetermined period is lapsed, pin #3 of the upper IC goes high, this switches ON the relay driver stage and also the lower IC pin #12 gets reset, this toggles the lower IC into counting mode.

After the predetermined period, pin #15 of the lower IC becomes high, which sends a logic high to the reset pin #12 of the upper IC, resetting it back to its original position......the cycle repeats, and goes on repeating as long as power is available.

The lower section can be upgraded for generating higher time intervals at par with the upper section by replacing pin15 with pin3 as already done in the diagram below.

The relay contacts are wired up to the motor for shuffling the egg orientation.

Incubator Timer Optimizer circuit using IC 4060

Using Rotary Switch for Adjusting the Time intervals


If you find adjusting the pot difficult and time consuming, you could easily replace them (P1, P2) with rotary switches as shown below. The involved could be also easily calculated with some quick and experimentation:


using rotary switch fixed resistors in IC 4060 timer circuit

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