Need help if my project idea is even possible.

Hello all this is my first post. please be gentle and kind :slight_smile: I have been messing around with arduino a little bit am excited to get more into it.

My project that I am looking to do...Not sure if its even possible. lets start off with I have some very nifty LED lights I installed into the steps of my deck. I picked up a timer for low voltage landscaping lights. Little did I pay attention to the LED's they are 12v DC and the wonderful timer is 12v AC. not going to work together. So my Idea is to take it a bit further and use Arduino to control the LED's. I would like them to be on a timer and be allowed to be dimmed. I would also like them to be able to be controlled by alexa or smart phone app.

So I am looking for any suggestions on what components to use. I have been looking at just 12v timers but not sure if that is the best way to go. Thanks for any suggestions and help.

Post links to the data sheets of the 12 volt timer and the LEDs.

The short answer is "yes".

The better answer is that you can easily control the lawn lights and the LEDs with just about any Arduino board plus a relay board.

Yes, you can do, with a micro controller, what you presented as a project idea.

These are the LED's I have installed.

This was the timer i was thinking of using. I am not sure if it will even accommodate my needs.

Do you think that just using three relays each to supply a different voltage (dimming) and just an Arduino UNO with WIFI will work?

The second link tells about 18 feathers but not how to address them.
Dimming LEDs using relays will not work. For that, use PWM and N-channel logic MOSFET transistors.

Please excuse my attempt at a diagram. First time doing one. I did some research and if I am understanding things correct. This is what you mean by using PWM from the arduino to a N-Channel MOSFET. Sorry if this is a bother i am trying to better understand more of how this all works.

Excellent diagram but polarities and some more need to be changed.
An N-channel logic(!) MOSFET needs to handle the low side of the load, the LEDs. The 12 volt GND must be connected to the Arduino power supply GND.

Okay, I think that I may have this. Please correct me if i am wrong. This is the new diagram i came up with.

That's much better but remove the ground connection of the rightmost LED! That would make the PWM useless and LEDs shining at full power.
I hope each LED represents a strip containg the neccesary resistors, or other current limiting.

I did not realize that I had that ground there still. I did know that one. The LED's are 12v so do i need resistors? wouldn't the PWM from the arduino be responsible for dimming the LED's?

Add a 180 - 220 Ohm resistor between the Arduuino and the transistor!
You alse need to change to another type of MOSFET. You need to use a logic N-channel MOSFET, not a "common" MOSFET! The gate - source voltage needed is too high for the IRF530. You've only got 5 volt there.

A naked little LED must have a resistor that limits the current. That's likely built in in the LEDs You use.

Yes. PWM stands for Pulse Width Modulation. When the controller pulse goes positive the MOSFET will conduct and let the current flow as long as the pulse is positive. When the pulse goes to zero the current is switched off. The normal frequency of the pulses is some 490 Hz. A wide pulse, or HIGH all the time gives full light. Shorter pulses reduces the light. That's the nature of dimming using PWM.

That was the MOSFET the program I used to draw the diagram with had. I did not change the naming of it to what I was going to use. This is the one I was planning on. By the way thank you so much for all you help.

That looks perfect. "Logic Level N-Channel Mosfet" is the correct name, "logic level"! They turn fully on from the 5 volt issued by the Arduino.

Now The real fun part. I have to figure out how to control all of this with a smart phone app and alexa. Got some more research to do now. :o

Make a simple Arduino sketch that verifies PWM and the LEDs! Then go ahead and work with BT, Wifi or whatever You're thinking off! Don't smash all if it toghether and then start coding! Thai's a recepee for quadrupled trouble.

Use the words "controlling alexa with esp32" in your internet search engine. Heck, there is even a library available.