Delay timer relay control connection problem

[pramodmani]

Hi,

I'm making an automatic fish feeder for my aquarium that'll switch on for 10 seconds every day at a set time to feed the fish.

Attached is the circuit diagram I am using. I have tried to explain everything graphically. I'm not sure where I am doing wrong as this circuit isn't working as it intend to.

There's also an YouTube reference link I have provided.

https://goo.gl/5cve1V

I have taken inspiration from this user and his circuit seems to be working fine. However, his wiring connection is not clear.
Can you please help me figure out?

 

[Bluejets]

Circuit looks ok BUT there is an error in the marking of the output relay connections.

ie your drawing shows the fish feeder connected to n/c and common

whereas the web link to a similar unit shows the same terminals as n/o and common.

So your should still work, just markings are wrong.

I did notice the input to initiate the timer is shown as "trigger".
Normally this is taken high/or low depending on the circuit , for a short period, not normally 1 minute as the time clock does.

Don't know if this affects the circuit or not.

Failing to have a proper spec sheet, can't help much more than that I'm afraid.

 

[Kiwi]

Shift the +12v from Normally Closed to Common.
Shift the fish feeder from Common to Normally Open.
Apply a brief +12v pulse to the Trigger Line.
Q1 - Does the circuit board power the fish feeder for 10 seconds and then switch off?

Now apply +12v to the Trigger Line for 1 minute.
Q2 - Does the circuit board power the fish feeder only once and then stop, or does it power it several times until the Trigger Line is disconnected?

 

[kellys_eye]

If the timer control has simple normally-open contacts then you don't need the 12V adapter for the 'trigger' voltage - all you need do is feed the 12V from the 'top' 12V adapter to the trigger input via the n.o contacts in the timer controller.

It may be that the timer used in the example shown DOESN'T have normally-open (volts-free) contacts available but there are many version of that timer that DO and fitting one will reduce the complexity by removing the need for the second 12V power pack.

 

[Bluejets]

Photo shows a relay adjacent to the output terminals. Voltage free would be a fair assumption. Notes also refer to powering of relay.

 

[pramodmani]

Shift the +12v from Normally Closed to Common.
Shift the fish feeder from Common to Normally Open.
Apply a brief +12v pulse to the Trigger Line.
Q1 - Does the circuit board power the fish feeder for 10 seconds and then switch off?

Now apply +12v to the Trigger Line for 1 minute.
Q2 - Does the circuit board power the fish feeder only once and then stop, or does it power it several times until the Trigger Line is disconnected?

Thanks Kiwi. I'll try your solution. My response to your questions:

1) Yes...the circuit powers the fish feeder for 10 secs(or whatever time is set in the relay timer) and cut off
2) The relay timer receives power from the mains timer for 1 min. So, ideally the relay timer should get activated only once during the 1 min and should not restart till the next day when the mains timer gets activated again

 

[Bluejets]

Kiwi was asking you to follow a certain sequence and give an either/ or reply to his query.
This would then narrow down the problem.
However, your reply seems to quote how you think the device should work.

 

[pramodmani]

Kiwi was asking you to follow a certain sequence and give an either/ or reply to his query.
This would then narrow down the problem.
However, your reply seems to quote how you think the device should work.

Thanks for pointing out. I'll try the sequence and respond to Kiwi

 

[pramodmani]

Shift the +12v from Normally Closed to Common.
Shift the fish feeder from Common to Normally Open.
Apply a brief +12v pulse to the Trigger Line.
Q1 - Does the circuit board power the fish feeder for 10 seconds and then switch off?

Now apply +12v to the Trigger Line for 1 minute.
Q2 - Does the circuit board power the fish feeder only once and then stop, or does it power it several times until the Trigger Line is disconnected?

Hi Kiwi,
Q1 worked. However, in Q2 gets repeated till the main supply is off

 

[Bluejets]

As mentioned before, difficult to say without any spec sheet for the timer. However, as I suspected earlier, the trigger input requires a short pulse rather than a continuous high for 1 minute or whatever. With timer circuits this usually has to be shorter than the output pulse. So it appears a bit of re- design will be required for the trigger. This may be as simple as a cap in series with the trigger input but I don't have time to try it. Again, a spec sheet would be handy.........

Edit........................Aheeemmmm


Seems there are 2 types of timer........

https://www.amazon.com/gp/product/B00GIBTQMI/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Go down to the reviews.......

First, there are at least two variations of this timer which look identical but are completely different. For the simple delay variation (the one you want and think you are getting but may not), the following are simple instructions without a lot BS.

To start timer with a +12 volt signal, connect +12V to input. Can be short or long. Timer stops at the end of set delay
To start timer when +12 volt is applied, just connect the input to +12 volts and leave it there.


mmm...more reading...and still confused....not very clear just what is what with Chinese stuff.