Timer circuit design needed and I'm too dumb to figure it out

Thread Starter

freewaydesigns

Joined Oct 16, 2019
6
I have an outdoor strip light from Wide Loyal (120V power supply, 12V circuit, ~11.0W) that I want to put on a conditional timer. Conditions are as follows:
-Indoor light switch turns on and off light
-Proximity switch at gate for when the gate opens, it turns the light on for 2 minutes even if the indoor light switch is off
-Motion sensor at front door (around the corner from where the gate is) that turns on the light for 2 minutes even if the indoor light switch is off
-Circuit will be outdoor subject to -40°C to +40°C temperatures in a moisture proof box

I have seen timer relay boards online, but I want something where I didn't need a separate 12V supply. Is there such a thing? Forgive me if this request sounds dumb, I am very new to circuit design, but am looking to learn.

Thanks in advance for all of your help!!

Nick
 

djsfantasi

Joined Apr 11, 2010
5,597
Can you explain in more detail what you mean by “120V power supply, 12V circuit”?

Do you mean that the strip plugs into a 120V outlet which passes through a converter whose output is 12V? Or something else.

The light switch, proximity switch and motion detector all can control the light independently. There is one more input, which replaces two of these inputs. that I’ll describe in the next paragraph. Thus, with one side of each sensor/switch connected to a common and the other side is input to a controller or logic board.

You’ll need a two minute timer. One timer can be shared between the proximity switch and motion sensor. Their outputs are joined to switch on the light and start the timer. The timer output is the second input to the controller board. If the timer is on or the light switch is on, your strip illuminate.

More details including powering all this, depends on your answer to my first question.
 
Last edited:

djsfantasi

Joined Apr 11, 2010
5,597
Or if you can code, you can use a microprocessor. The Arduino family is easy to begin with. And there are several models. A Nano might be enough. Or an ATTiny85 which also uses the Arduino IDE and C++ language.
 

Thread Starter

freewaydesigns

Joined Oct 16, 2019
6
Thanks for the reply djsfantasi. The strip has a wall plug for 120VAC. There is an inline AC to DC converter on the cord but does not look like there is any transformer. The website says 12V circuit.

I'm afraid of using a microprocessor like an arduino because of temperature and longevity. I heard they don't last long.
 

jpanhalt

Joined Jan 18, 2008
7,893
Wire your switches in "parallel", that is "OR'd." Use individual timers for the two that require timers as there is a possibility that each will turn on at a different time.

Edit:
Here is what I meant by parallel:

upload_2019-10-17_5-24-50.png
 
Last edited:

Thread Starter

freewaydesigns

Joined Oct 16, 2019
6
Wire your switches in "parallel", that is "OR'd." Use individual timers for the two that require timers as there is a possibility that each will turn on at a different time.

Edit:
Here is what I meant by parallel:

View attachment 188212
Can it be wired so sensors are in parallel before the timer so I only need one timer? What happens in either case if both sensors are activated in less time than the timer is set?
 

jpanhalt

Joined Jan 18, 2008
7,893
Draw what you are proposing, and you will see the reason.

You want each time light to be on for 2 minutes. With only one timer, if one switch (say S2) starts the timer, and the other switch (S3) is subsequently activated, there are two options. The timer can be restarted ("retriggerable") or the timer just continues and does not restart (non-retriggerable). In the former case, the light controlled by S2 will be on for more than 2 minutes; in the latter case, the light controlled by S3 will be on for less than 2 minutes.

So, to meet that requirement for each light, you need independent timers.
 

Thread Starter

freewaydesigns

Joined Oct 16, 2019
6
Draw what you are proposing, and you will see the reason.

You want each time light to be on for 2 minutes. With only one timer, if one switch (say S2) starts the timer, and the other switch (S3) is subsequently activated, there are two options. The timer can be restarted ("retriggerable") or the timer just continues and does not restart (non-retriggerable). In the former case, the light controlled by S2 will be on for more than 2 minutes; in the latter case, the light controlled by S3 will be on for less than 2 minutes.

So, to meet that requirement for each light, you need independent timers.
Thanks Jpanhalt. Is there a timer board that I can but off the shelf that will work for this? I found a few with 120V relays that have a 12V switch in, but the 12V will need power from a separate transformer circuit right?
 
Top