How to Wire Delay Timer Relay for Automatic Fish Feeder Circuit Like YouTube Example?

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://www.youtube.com/watch?v=ld4f10OLMgU

(from 5:08 onwards)

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?

Pramod, if you want help then you need to give us more info, not just " this circuit isn't working as it intend to." How IS it working, what is it doing? nothing at all? switching on for too long? switching on when it shouldn't?

One difference I can see from the YouTube video is that the guy there is using a mains timer (the 24 hour one) which closes a pair of contacts to trigger the timer. Yours puts out mains which you have going to a 12V adapter feeding into the timer. It's probable that the timer will not trigger on +12V as you have wired it, but needs a short circuit between the trigger line and the - power line. To do this you would have to put a relay with the coil operated by your 12V adapter, and Normally Open contacts connected to your timer.

If you don't have the knowledge to do this I can explain a bit more, maybe with a diagram, but relays are pretty simple, you can pick one up from an auto store (they use them for headlights). Good luck / David

Pramod, if you can give me a link to the datasheet for your timer module that will help me give a more definitive answer. I found some that look like it but no datasheets.

I agree with what Davis has sad Pramod.

Pramod

As David has pointed out you have not described the problem. However, from what I see at first glance and without really going into how the unit works the fish feeder will be continuously on, except for the 10 secs timer period. The output is connected to the Normally Closed (NC) contact- i.e. when the relay is inactive the NC contact is shorted to common output.

In my opinion you should connect the "+" line to the Normally Open terminal on the right hand side

David,

Let me explain better :

What I want - I need to supply my fish feeder for only 10 seconds. For this I am using an 12 volt delay timer relay and set its time to 10 seconds. Since this requires 12 volt as input, that's why I am using an 12 volt adaptor. Now, I want this feeder to run daily once at say 7 am. For this I am using a 24 hr mains timer that's set to supply power at 7 am for 1 minute to the fish feeder. When this timer activates, I want my fish feeder to run for 10 seconds and stop.

The problem - When the 24 hrs mains timer gets activated, the delay timer relay also gets activated as desired. However, it doesn't get cut off after the 10 seconds time set ND keeps looping till the full 1 minute the 24 hr mains timer is activated.

The delay timer relay doesn't need continuous supply for a minute. Rather, it only needs an brief pulse to get activated and not loop again.

Hope this was clear. If you can explain with a diagram, it'll be very helpful as I am not an electronics guy and still learning.

I didn't recieve any documentation with the delay timer.

Hi Pramod

As my colleague (and compatriot - we're both from Zimbabwe!) spotted, you should be using the NO (Normally open) output of the timer to switch your feeder, not the NC (Normally closed). Your first step would be to try the NC and see if that works.

I managed to find a diagram of how the timer module works. It does need +12v to trigger it so your wiring is right there. It is possible that if you leave a constant 12V on the trigger it will stay triggered (and operate your fish feeder) until the trigger is removed, and then keep operated for another 10 seconds. but it's just as probable that once triggered it will just go for 10 seconds even if the 12V trigger is still there. I could not tell this from the diagram I saw.

You can test this easily though. Remove the trigger wire only from the timer, but leave the 12 power and the fish feeder connected. Briefly short the trigger connection point to the +12V point (a bent paper clip is handy for this) and the timer should operate for 10 seconds (you should hear the relay click at the start and end of this time as well). If that works, try keeping the +12V to trigger connection on longer than 10 seconds and see if the output stays up all the time you leave the connection on.

Lastly, if neither of the above works, try shorting the trigger connection to the -12V connection and see if that works.

Let me know if any of the above helps you out and we'll take it form there

Cheers // David