Arduino smart light

Good day! I’m fairly new to Arduino and me and my groupmates making a project: a smart lighting system using Arduino, LDR and a 12v fluorescent light (the tube) that has a varying brightness depending on the light intensity the LDR receives. We’ve researched about projects/studies about this and almost of all of them utilize LEDs because of the low voltage. So to improve it, we proposed using fluorescent light to brighten up a room. My concern is that, as what I’ve understood, the Arduino gives offs only 5v and it may not light up to its brightest. Can we use a converter circuit (5v to 12v) of some sorts between the Arduino (with the LDR) and the fluorescent light? Or could we just amplify the voltage using a battery? Thanks in advance :slight_smile:

Your best bet would be to use a relay. You can get modules (like this) which are already designed and built to be connected directly to your board.

A fluorescent tube needs considerably more than 12V. A typical small fluorescent tube circuit that runs from 12V incorporates a high-frequency step-up circuit. It doesn't just take 12V and apply it to the ends of the tube. A 12V circuit that I made a few years ago for a 4W F4T5 (6" x 0.5") tube applies 154Vp-p to the tube. (Not a dimmable circuit.)

Dimming a fluorescent tube isn't as easy as simply reducing the voltage like you would in an incandescent lamp, either. And you'll never get the nice smooth transition that you get in an incandescent.

What sort of tube are you talking about, and what ballast did you plan to use?

Do you have a decent amount of electronics knowledge? Unless you have a ready-made module that can drive and dim a fluorescent tube, you're in for a bit of a steep learning curve.

Edit: You won't be able to power it from the Arduino's 5V rail. It will use too much current, even if it's only a little T5 4W tube.

hey DreamyCrown :)

yes you're right you can't power up your fluorescent light directly using arduino I/O pin, instead you can use 5v relay. If you don't know what relay is.. its a menchanical switch (because it's actually has moving part in it) but you can control this switch electrically using arduino I/O pin. If you familiar with transistor, relay is just like transistor but can handle a lot (what I mean by a lot is like A LOT) more voltage and current. The circuit required is pretty much basic and super easy, just google or youtube it and you'll find a bunch of tutorial.

I hope this can help

Abizhar: hey DreamyCrown :)

yes you're right you can't power up your fluorescent light directly using arduino I/O pin, instead you can use 5v relay. If you don't know what relay is.. its a menchanical switch (because it's actually has moving part in it) but you can control this switch electrically using arduino I/O pin. If you familiar with transistor, relay is just like transistor but can handle a lot (what I mean by a lot is like A LOT) more voltage and current. The circuit required is pretty much basic and super easy, just google or youtube it and you'll find a bunch of tutorial.

I hope this can help

Hey Abizhar, he wants to dim the fluorescent tube, not just turn it on and off. Will a relay do that?

and a 12v fluorescent light (the tube) that has a varying brightness depending on the light intensity the LDR receives.

Doesn't anybody actually read the opening post before contributing their 2c 1c worth?

anyone read that he wants dimming ? got any links to relays that can dim a circuit ?

A fluorescent light requires about 2,000 volts. so, you have to have a thing between the Arduino and the 'tube' that thing is called a ballast. A fluorescent ballast can be purchased that has dimming capabilities. in fact, in the country of California, they require all new commercial lights to use dimming ballasts.

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in the end, all the other groupmates use LED's because they cannot afford the cost of the dimming ballast and the life of an LED light is much less expensive than the cost of a dimming fluorescent. that would mean that if you needed say, 2,850 lumen’s (typical 4 foot fluorescent tube) the cost of the fluorescent vs. LED, the LED will be less expensive. the LED will last about 5 years before it dims to the point of needing replacement.

LED's dim over time, just slower than most other lights. in 5 years they will be some percentage less bright than a new one.

if you price up the cost of LED for 5 years of use the costs for replacement of fluorescent in that same 5 years, with possibly a ballast replacement at some time, the LED wins. when you add up the cost of an electrician to change the ballast and lamps, it gets worse for the fluorescent.

when you add up the cost of energy to run the two, the LED wins again.

dave-in-nj: anyone read that he wants dimming ?

I did, but it seems that no one else did. :)

A fluorescent ballast can be purchased that has dimming capabilities. in fact, in the country of California, they require all new commercial lights to use dimming ballasts.

It might take some searching to find a ready-made dimming ballast with digital control (to control it from the Arduino) suitable for 12V operation.

P.S. Is California really a country in it's own right now? :D

Man you guys are harsh but fair call, I didn't read carefully enough.

DreamyCrown, you can find pretty bright LEDs these days. For example, downlights made for houses (in Australia at least) are almost all LED. If you get 12V ones, you could control the brightness via a power MOSFET and PWM and you don't have to worry about playing with dangerous voltages.