Multi-zone 12-Volt Lighting Control Questions

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GuyManDude
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Joined: Sun Feb 11, 2018 9:14 pm

Multi-zone 12-Volt Lighting Control Questions

Post by GuyManDude » Sun Feb 11, 2018 9:32 pm

Hi, All,
I'm all new to the world of Arduino, but I am thrilled with the potential. I have a project which I am contemplating, but I need someone's advice/expertise to know what is required to pull it off. I would like to create a control for up to 15 independent zones of 12-volt lighting. 10 of the zones need to have the ability to utilize a digital potentiometer for dimming. To start with, can I pull this off with an Uno R3? I know I am limited with outputs. Can I use a single output to address 4 lighting zones using PWM? I researched a few digital pot's that can have up to 4 independent controls. If this isn't possible, are there output expansion shields available? 73 more questions await, but I'll stand by for a reply...

Thanks in advance

n1ist
Support Volunteer
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Joined: Wed Mar 22, 2006 11:02 am

Re: Multi-zone 12-Volt Lighting Control Questions

Post by n1ist » Tue Feb 13, 2018 9:35 am

What are the "lighting zones" and how are they controlled? Most digital pots have limited voltage ranges and are not isolated from ground. You need to start by figuring out the voltages, currents, signal types and format, distance, and isolation needs before going further. Also, how do you want to control this? Network, physical controls, a touch screen?
Once you figure that out, you can then determine if the Uno is good enough, and what interfaces you will need.
/mike

GuyManDude
Posts: 2
Joined: Sun Feb 11, 2018 9:14 pm

Re: Multi-zone 12-Volt Lighting Control Questions

Post by GuyManDude » Tue Feb 13, 2018 10:33 am

Hi, Mike. Thanks for the reply.
The project is a lighted dollhouse. I currently have 8 dimmable zones controlled with a push-button switch and a 10k rotary pot on each, with a red indicator LED on the panel. The dimming circuit is a TIP31A with a 100ohm resistor. The lights are E5 base LED’s. I have a 12v 2-amp power supply from an old computer. Likely the entire current draw with everything on is no more than 0.5 amps. I’d like to retain the manual control (maybe upgrade the switches) but also have an IR remote to cycle thru zones and use the up-down volume buttons for dimming. Pretty simple, but I don’t know if I can have up to 12 dimmable zones and maybe 5 additional on-off zones controlled with an Uno.
You don’t have to give too much technical detail, as figuring it out myself is half the fun, but if I know I could use a single output from the Uno to control more than one circuit based on PWM and using a dual or even quad digital pot, that would help. In other words use one output on the Uno board for more than one zone control.
Any suggestions would be great :)
GMD

n1ist
Support Volunteer
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Re: Multi-zone 12-Volt Lighting Control Questions

Post by n1ist » Wed Feb 14, 2018 6:28 am

Certainly doable. I would not bother with digital pots in this application; I would simply PWM the LEDs. Probably the easiest would be to use would be the https://www.sparkfun.com/products/10616 TLC5490 board (or https://www.sparkfun.com/products/10615 shield). On either board, you will need to remove all of the 2.2k pullups on the output since your LEDs are running on 12V. If you need to drive LEDs at more than 100mA or so, you would need to add a MOSFET between the TLC5490 and the LED.
Depending on your programming, you could either dim the zones or simply turn them on or off. If you have other loads to control, I would use a GPIO pin on the Arduino to drive a MOSFET to control the load.
As for the user interface, you could use the pots connected to the ADC pins directly or use an analog mux to reduce the number of pins needed. Alternatively, you can use a keypad or even go fancy with a touchscreen LCD...

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