I've been searching around a whole bunch and I can't seem to find information for this project I want to do.
I've got this painting I'm working on, where each layer is painted on a sheet of plexiglass. There are 13 sheets so far (1' x 4' each)
The idea is that each colour is on its own layer and everything has its own depth.
I want to frame these sheets of plexiglass, and include strips of LED ribbon across the top edge. The frame would be thick enough to house power supply and arduino board.
Thats just me with a light shining it across the various layers. And that is the effect I want to automate.
Problem is, I have programming experience, but little to no hardware experience. I'm trying to determine exactly what I need to be able to pull this off. I'm jumping into this head first, and really would appreciate any guidance you could offer!
Been trying to find tutorials, but all I can find are RGB LED tutorials (I just need white, and to be able to turn off strips of LEDs, up to 6 strips)
Turning one or dozen of LED on/off is same.
As long as you know the difference between parallel and serial connection, mainly how to control the current thru each type of connection.
Either way - you will be better off not connecting the LED's directly to Arduino I/O pin(s). Microprocessors are generally not designed to have full current load on their I/Os. They are controllers first.
And you can get up to 8 " channels" Arduino compatible relay shields to carry the load easy.
Good luck
Vaclav
Do you know how much current it will take to drive each LED strip? If it's 150mA or less, I've used the TPIC6B595 to control lengths of LED strip in my workbench light. You'll need to do the maths on your specific strip but each of these can sink current for 16 strips so a great deal of flexibility.
If they need more current, you might need to look into a MOSFET for each.
I'm not sure what the amp draw is going to be -- the LED ribbon I saw in the store was going to be about 3 amps for 18ft of ribbon. However I would be chopping those down into 3 strips of 6ft.
Can anyone recommend which Arduino would be suitable for this project? Like I said before, this is all brand new to me, starting from scratch.
I'm thinking the Micro would be optimal for its small form factor -- ??
Any would do, if it does not need to have USB access when complete, then a ProMini even. Use a USB/Serial adapter for downloading code, remove it when you field the completed unit.
You WILL need external hardware to drive current for the LED strips. The strips generally need 20-mA for every 3 LEDs. Each group of 3 uses about 2 inches of length, so 6 groups/foot x 6 feet = 36 groups, x 20mA/group = 720mA/strip.
I would use 6 Logic Level, Low Rds, N-channel MOSFETs, one per strip, each controlled by a PWM output so you can have brightness control also.
With their 0.039ohm of on-resistance, and 0.72A of current, the parts will dissipate about 20mW, nice & cool, so no heatsink should be needed. (P=IIR)
Use a 150ohm resistor between arduino pin & gate, and a 10K from gate to ground to keep them turned off when the arduino is powering up or recovering from a reset.
+12 to + on the LED strips, transistor connects to - on the LED strips and makes the connection to Gnd to turn them on.
What you end up electrically is this. If you examine the LED strips, you will see wide + and - columns running the length of the strip.
These connect to +12V and to the transistor.
