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Topic: Automated LED for shop (Read 11542 times) previous topic - next topic


OK, I have been planning a lighting system for the shop I am building.  I do not have code or exact specs yet, I have searched the forums and have not seen anything similar (let me know if I missed it).

Essentially I want to use a Xbee Arduino setup with smartphone (or similar) control.  I will also have a few wall switches. 
The lights are going to be 50W 5000lm 6500K Integrated Square 1-LED White Light Module (32-34V) One per fixture
I will have a massive heat sink for each light.
Each LED light will be controlled individually or in pairs (depending on power supply options) It will use Xbee to communicate between lights.
I want to use a proximity sensor to sense where people are on the shop and adjust lighting (bright near the people dim in the rest)
I would also like to have a light sensor to make the system automatically compensate for ambient light (if dim more light, if there is tons of sunshine less light.

Issues I see are that I am dealing with high power LED's that require much more than the Arduino can control with the PWM.  How does one control a 50W LED with dimming, and how do you supply proper power for the LED?
Now there are going to be around 16 of these beasts in the shop, that is where the Xbee comes in, I hope they will all talk and figure it out amongst themselves and not need me to adjust the lighting.

Yes you guessed it I am a NOOB to Arduino.  I have been lurking in forums playing on Google and trying to figure all of this out myself.  I hope that one of you will find this project interesting and we can collaborate.  I have done lots of residential wiring, alarm systems in cars and houses, built computers, some circuits but when it comes to figuring out how to get these parts to play together I am a bit lost.  I do not want to burn the place down or end up spending $200 per light, so I hope there are some cheap easy ways to accomplish this.

Thank you in advance!


You might find some joy in the Motors Mechanics and Power section. A 50w LED more or less equates with something heavy that moves.


Thank you for the reply, I have scoured that section and several other places and can not find a board that can control more than 25W.  Ideas or suggestions?


Also do I need one Arduino for each light or is thee a way to run 16 lights individually from one Arduino?  Seems like the biggest issue is the high power requirements.


You need an Arduino at every light.

Controlling leds with PWM can be done with a logic level power mosfet.
The problem is the power supply for the leds. They should be able to handle the PWM signal, and I don'w know if led drivers can do that.

I see this scenario: Everything seems to work so well that the lamps are mass produced and are selling good. When it is dark a person is in the shop, and the lights near him or her are on. That person uses a flashlight and switched it shortly on towards the lights above him or her. Those lights will dim, causing the lights further away in the shop to turn on. This starts a never ending wave of oscillation lights across the whole town.


Yes interior light sensing is more challenging.  I was hoping to be able to do something like the following

If presence detected in direct area light set to 35 lumens per SF (or adjustable)
If presence detected in another zone but not this zone dim to 20 lumens per SF
If no presence detected in all areas all lights off

I will have a few zonal areas like the main shop the paint booth, the shipping department and other areas.  So I will need to program say 5 zones with similar functionality but not interdependence.  In other words if no presence detected in the paint booth all lights off in the paint booth, regardless if all sensors detect people in all other zones.

I hope to be able to find light sensors that can detect specific light values and control the lighting dependent on that...  otherwise I will not be able to control lighting dynamically.  As you mentioned normal light sensors sold in hardware stores turn on or off lights at a dusk like setting so the lights turn on then the sensor sees the light bouncing off the walls and turn off the light, then the sensors see that there is no light and it turns on the light and so on.  I was at a store when a customer was arguing an employee about how the lights with a photocell should work inside because it works outside, it actually got heated bless the employee for his efforts but the customer just did not get that the light bounces around inside and outside it does not (laymen explanation).

So the big questions;
Which sensors give a specific value of light input to the Arduino board
How do you control a single 34V 1.6A led with dimming capabilities (or without for that matter)

How do you program this functionality.


If you want to compensate for ambient light, you are making an oscillator. Because the ambient light is also the light of the nearby lamp.

Take a look at the ABC guide, http://www.pighixxx.com/abc-arduino-basic-connections/
For example the mosfet on the bottom-left of "Card 3". Click on "Set 1 (Card 1,2,3)" to open the pdf.

This is a mosfet that can switch it, https://www.sparkfun.com/products/10213
Never mind that it is able to switch 30A. A mosfet of 30A is perfect to switch 1.6A.

There are so many light sensors.
You could connect an LDR and a resistor to an Arduino analog input (ABC guide, card 1, lower-right), 20 for 2 dollars on Ebay.
Or photodiode, 2 dollars on Ebay.
Or an expensive lux sensor.

For programming, start with the examples that come with the Arduino IDE.

How do you want to detect if a person is present ?
A PIR sensor only senses motion.
Perhaps ultrasonic ? But what if someone places a tall box under a lamp ?


Thank you for the link I will need to study that for a bit.

As you can tell I am trying to learn all of this so thank you very much for taking your time and hopefully in time I will get it all.

Honestly I still do not understand how to control the MOFSET from the Arduino and or how to wire it all up but given the correct layout I can solder like a mad man.  I have tried projects for years now and I am getting better.

I am thinking of using this https://www.sparkfun.com/products/9768 to sense the light it seems to have good control and variability.


So the Arduino can control many outputs, why can I not use one board, control 16 lights, have 16 photo sensors and, some number of proximity sensors?

New construction so wiring is not a big deal.


Sure, that is possible.
The wiring (and the costs to put them in place) could be more expensive than the Arduinos.
With long wires, the Arduino must have more protection against electrical spikes. Perhaps even optocouplers.

If you have a working module, you can make 16 of them. That is not hard.
An Arduino Pro Mini clone costs about 5 dollars on Ebay.
Making the modules to talk with each other, increases the complexity a lot.

On the other hand, having a single unit, will make it a lot easier to take all light sensors into account.
There is not need for the modules to talk with each other, since you have all the information in one Arduino.

I'm still curious, what kind of proximity sensors ?


Sorry I thought I had the link for the PIR sensor

that is just one option.

I was seeing the Arduino boards for around $25 so that is one of the reasons I was looking to reduce the number of boards.  Realistically I am doing my own wiring and wire is not that expensive especially when you consider that the shop is only around 2,500 SF so even the farthest out light is only around 60 feet away (at most).  I already have tons of cat5e wire which should work for data, power conversion can be done at the light.

Yes I am scared at how I am going to get 16 Arduino boards talk and listen to each other.  I was thinking that was going to be the Xbee, but again I am adding cost.

After more research I am beginning to understand the use and need for the MOFSET to translate the power from the Arduino to my power supply

But still need to verify NPN or PNP for these LED's


Are you going to put the mains voltage on a cat5 cable ? I would not recommend it.

If you choose the "Light to Frequency Converter - TSL235R", you have to measure the frequency. Perhaps there is a library for that. I don't know if the frequency signal will work with the cat5 cable.

For a mosfet, most of the time a N-channel mosfet is used.
But I don't know if the led driver is capable to be used with a PWM driven load.

For a 50W led, you need a big heatsink, perhaps even a fan.
The lower the temperature of the led, the longer it lasts.
I have a led like that, but only 10W. My heatsink turned out to be too small, so I had to lower it to 5W. I read that reducing the current to half of the maximum only lowers the light intensity by 20% or 30% or so, and the led will last longer. But I can't find it right now.

A PIR sensor detects motion. If someone stands still the lights will turn off.


No only data on the Cat5 not Power.

I am thinking of the power supply at each light one Arduino board near the main entrance to the building and multiple sensors around the building. 

For the UI maybe a touch pad?  Smartphone?  ideas?

Yes you need a HUGE active heatsink meaning a cooling fan nad large block of aluminum/ copper for these led's


Um, well there are products that can help with that...


So the CATkit is a shield which distributes 18 data channels over CAT5 cable. Each signal can be used for a sensor, an actuator or another device such as an LCD display.  This would be very appropriate for your project with a PIR sensor and a relay board controlled by a remote Arduino for example.  Local power would be provided by AC or battery to the relay and lighting of course.

(usual disclaimer - I am associated with SmartGreenHouse.org)
Don't breath in the magic smoke!


Thank you for the heads up on that, it is an interesting option!

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