Hi everyone,

Yet another new member who was drawn in by some of the previous discussions around integrating 12V DC PIR motion sensors with 12V AC landscape lighting. This one in particular was very helpful for me: Where to buy a 12 volt AC Motion Sensor (PIR) or can I buy the components?

Apologies in advance for the details. I'm trying to circumvent the "There's not enough details" and "Why don't you...?" responses. There will be questions at the end, I promise.

My main goal for my project was to illuminate our front porch steps to make them easier to navigate. The one porch light next to the front door does not illuminate them and casts a shadow down them. Older family and friends have indicated that it feels pretty dangerous for them.

My first attempt at a solution without having to run additional wiring were these lights: AURAXY LED Solar Lights Outdoor with Optical Lens and 3 Lighting Modes, Motion Sensor Wall Lights. I have several of these around the house and they work great in locations that get enough sunlight to keep them well charged. The challenge with the front porch steps is that they are covered and the only location that gets any useful light is at the bottom of the steps. When people are leaving from the top of the steps they motion detector doesn't get triggered. In addition, in the winter there isn't enough sunlight to charge the light to do any meaningful good.

Given that we have renovated the entire house and run new electrical everywhere, I considered going the route of running regular electrical lighting to the corner and setting up some additional lights over the steps. I backed off this option as I didn't want always-on lights nor did I want the bright flood lights that typically come with motion sensors.

In my mind, my criteria for a solution eventually evolved into the following requirements: 1. Something that was a little more elegant and subdued than flood lights. 2. Something that wasn't always on (aka timer or photocell). 3. But that is triggered by movement on the driveway and motion at the front door (dual motion sensors).

For the elegant aspect, I ran across these 10-Watt Equivalent Black Integrated LED Outdoor Landscape Path Light which are only 3"x3" and can easily be added to the stairs. This obviously then puts me in the landscape lighting arena which I was unfamiliar with so I purchased the following:

• SUNVIE 120W Low Voltage Transformer Outdoor Landscape Lighting Transformer with Timer and Photocell Sensor Waterproof 120V to 12V/14V AC Low Voltage Landscape Transformer for Spotlight Pathway Lights
• Wirefy 12/2 Low Voltage Landscape Lighting Copper Wire - 12-Gauge 2-Conductor 100 Feet | Low-Voltage Wire | Low Voltage Wiring | Low Voltage Wire 12/2 | Landscape Wire 12 2
• SUNVIE Low Voltage Wire Connector Fastlock2 Landscape Lighting Wire Connectors Waterproof Low Voltage Connector 12-18 Gauge Landscape Wire Connector for Landscape Light Pathway Lights

The transformer has options to meet my not always on with both timer and photocell options. However, I just don't feel the need to have the new step lights on all the time. It's not the cost to run the lights all the time but rather I just don't want them on all night. Or off when I need them and it is outside the schedule. Basically, I really just want these new lights to kick on for someone approaching the steps from the driveway or someone leaving from the front door.

The first challenge was figuring out how to wire two motion sensors in parallel. I found enough resources online to give me confidence to move forward with that approach.

The next challenge was finding a stand-alone motion sensor. Try as I might, I couldn't find any stand-alone landscape lighting motion sensors. There are certainly lots of individual lights with sensors but nothing to control a circuit. Nothing at Home Depot in the Hampton Bay line with the lights I chose (although there is this option which appears to be able to control a group of lights but the reviews ultimately said it won't work the way you think it will work: 15-Watt Equivalent Low Voltage Black Motion Sensing Integrated LED Outdoor Stair Light with Frosted Acrylic Lens). Nothing in the Sunvie line where the transformer and connectors came from. Nothing in the Volt line which is another landscape lighting brand.

In the end, I did go the route of getting the HiLetgo Outdoor PIR DC 12V Automatic Infrared PIR Motion Sensor Switch for LED Flood Light (before finding this thread). While definitely a bit of a hack, it seemed like this was going to be able to work and wasn't anything outside of my ability. Keep in mind, this was before I found the other thread and before I paid attention to the details. I was just going on "12V" and "low voltage". You see where this is going.

So I got all the parts and (smartly) decided to wire up a little test rig since I was new to landscape lighting and wiring up parallel motion sensors. I got everything wired up, plugged it in, and then got two pops, one from each of the PIR motion sensors. Long story short, I had glossed over the important AC vs DC details and destroyed the PIR sensors. Both of them now have a rattle from whatever part blew. A valuable lesson was learned.

Thanks to the other thread and Ya’akov's patience and diagram in that thread I posted, I now realize that I need a rectifier to switch AC to DC to power the PIR sensor and then a relay to allow the sensor to trigger the lights. These were the options listed in that thread:

• LM7812 L7812 Voltage Rectifier Regulator 12-24V AC or DC to 12V DC Power Supply Converter Module Board
• TWTADE/DC 12V Electromagnetic Power Coil Relay 10A 8 Pins 2DPT 2NO 2NC with Indicator Light and Socket Base -YJ2N-LY

Which leads me to my questions:

1. Regarding the relay. There are multiple options on the page including a DC 12V and a AC 12V. I'm a little unclear if I'm supposed to choose the option that corresponds to the source or the output. I believe source (DC 12V) but I would like confirmation.

2. In the other thread, rpiloverbd made the comment " 12V AC PIR is not available. You can use adapters to achieve your desired voltage level to run the PIR." Based on my research the past week, I believe him. The only exception I've found is the RAB STL12V which appears to support both AC and DC but they are $100+ each and while they have a great reputation, it seems like overkill. My question: Why aren't there more 12V AC PIR options? As noted by all the other threads I've seen around the internet on the topic, it seems like there is demand.

3. Regarding the rectifier, can I just have one rectifier upstream of both PIRs (probably in the junction box with the 1st PIR) and then send the power down to the 2nd PIR?

4. Regarding the relay, can I just have one relay downstream of both PIRs (probably in the junction box with the 2nd PIR) and then send the AC current down to the lights?

5. Any reason I can't or shouldn't use the rectifier and relay outdoors, in a sealed junction box, under a porch roof where they will not get wet?

Thanks in advance for any comments or guidance!

 

I spent some time since my initial post to do more research and to put together a working tabletop example of integrating my 12/14VAC landscape lighting with a 12V DC PIR motion sensor. Most of what I put together was based on the discussion thread that I linked to in my original post.

I’ve attached a diagram of what I put together to try to add some additional clarity on the connections.

in addition, here is a video of my tabletop setup that I put together to test it out: Controlling 12V AC landscape lighting with 12V DC PIR motion sensor switch

A couple of notes:

• The notes and reviews on the rectifier said that in order to get 12V DC out, you need to come in with at least 14V AC. Fortunately the transformer I am using has both 12V and 14V outputs. And fortunately the lights I am using support 12-15V AC.
• As mentioned in the video, the connections on the rectifier are much smaller than the wiring I am using so I used speaker wire to step down the wire size to fit that connection.
• The relay that was recommended is a dual-pole, dual-throw relay. It took me a bit to wrap my head around it but that is some cool functionality. Especially nice because I was wondering if I would be able to put a switch in the system as well. Turns out I can with the dual-throw mechanism.
• I also recommend reading the Amazon reviews on the relay. There is no doco with the relay but several reviewers put it in very clear English on what connections do what.

Hope this helps someone else!

 

For your application, you should choose a relay rated for DC 12V if you are controlling the relay with a DC 12V PIR motion sensor. You can use the rectifier and relay outdoors, provided they are housed in a sealed junction box to protect them from moisture and dust.