Manual Wiring analog 5050 LED

[djmoney]

Can anyone help with wiring some 5050 LEDs?   I want to take some bulk 5050 RGB LEDs  and wire them to potentiometers and manualy control the RGB values of the strips.  I want to make inexpensive 3d Printed LED Lamps. 

 

This was my thoughts.  Is there anything else I need?  

 

 

 

[iamdarkyoshi]

You can't put potentiometers on each channel, you need to pulse width modulate them.

[djmoney]

Is it possible to do that with out a micro controller?

[bob345]

Like @iamdarkyoshi said, you will not have a fun time if you try and make a dimable rgb led without pwm. All led's have a "cutoff" voltage. That voltage is the threshold at which the led itself will begin emitting light, but the intensity of the light at this point will be much higher than you would want for a dimable led. That is more or less why you need pulse width modulation. By varying the duty cycle of the voltage applied to the led you have a much wider useable range or brightness. You effectively are still giving the led the proper voltage at all times, but overtime the average time the led is "powered" gives you an effective lower voltage and current.

[SquintyG33Rs]

despite the facts stated above lian-li cases have this dial type of setup on some of their older cases. it's just more limited but it doesn't mean you can't do it since it's simpler and much cheaper too

[djmoney]

I understand what PWM is.   

 

What I am trying to do I make this controller for less than one of those control box from amazon.  

 

https://www.amazon.com/eTopxizu-44Key-Remote-Controller-Light/dp/B004IJFAMW/ref=sr_1_3?ie=UTF8&qid=1506652054&sr=8-3&keywords=5050%2Bled%2Bcontroller&th=1 

[iamdarkyoshi]

6 minutes ago, djmoney said:

Is it possible to do that with out a micro controller?

You can use a several 555 timers but by that point, you might as well buy a 1$ controller on ebay...

[djmoney]

Just now, iamdarkyoshi said:

1$ controller on ebay..

The only reason I don't want to use a micro controller is that they tend to cost more than the boxes on amazon.  I barely know how to code.  I mean I can google and follow direction.  

I guess I am open to Ideas.  I basically want to be able to make this thing for less than $5.   I have the LEDs, Plastics, bulk wire, and ac adapters.  

[iamdarkyoshi]

1 minute ago, djmoney said:

The only reason I don't want to use a micro controller is that they tend to cost more than the boxes on amazon.  I barely know how to code.  I mean I can google and follow direction.  

I guess I am open to Ideas.  I basically want to be able to make this thing for less than $5.   I have the LEDs, Plastics, bulk wire, and ac adapters.  

You'll either need a controller or just use switches for each channel. You'll have 7 colours using just switches.

[djmoney]

I think I am just going to eBay the controller boxes.  they are as low as a $4 shipped from the US.  

[mariushm]

You need to use proper LED driver chips.

 

Here's a huge selection of led drivers : https://www.digikey.com/products/en/integrated-circuits-ics/pmic-led-drivers/745

 

For just a single 5050 LED, you can use a cheaper led driver with only 3 or 4 or 8 channels, and use only 3 channels out of them. The microcontroller  sends commands to your led driver and the led river controls the brightness of each led (or leds).

You can use push buttons or potentiometers or encoders to set the brightness of each color. For example, have 5 buttons ( R G B and -  + ) so to adjust one of the three colors, you press on red, green or blue and then adjust brightness with [-] or [+] buttons. Or you could have 3 buttons one for each color and then use an encoder (like a potentiometer, but which spins forever and just sends pulses each time user turns left or right a particular amount, so the code in your microcontroller uses that to adjust between 0% and 100% the brightness for the selected color.

Or you can go even simpler, with just three buttons...  [-] [ s ] [ + ]  you press S (select) to select the color you want to adjust brightness (and you see which color is active by showing only that color), press S multiple times to go through the three colors. Then press - and + to adjust brightness of that color. If no input within 5 seconds or so, exit adjust mode and show all three channels.

 

This would be doable with a microcontroller that has 3 inputs and 1 output pin, so for example a 6 pin or 8 pin PIC10F / PIC12F microcontroller that's less than 0.65$ ... here's an example: https://www.digikey.com/product-detail/en/microchip-technology/PIC12F508T-I-SN/PIC12F508T-I-SNCT-ND/5013536

 

It could be possible even to wire the 5050 led directly to the outputs of the microcontroller and turn on or off each output lots of times each second in order to adjust the brightness of each color, but led drivers would be the smart way.

 

Here's an example of a super cheap and easy to use led driver with maximum 4 channels (max 20mA and 5v per channel) and 16 levels of brightness for each channel: https://www.digikey.com/product-detail/en/issi-integrated-silicon-solution-inc/IS31BL3212-STLS2-TR/706-1210-1-ND/4286428

 

Each time you want to adjust brightness you just send 16 bits through a pin of that chip, where each 4 pins set the brightness of each channels.

 

For higher current, you could use something like this : https://www.digikey.com/product-detail/en/stmicroelectronics/STP08DP05TTR/497-6029-1-ND/1632058

It has 8 channels, and each channel supports a strip of leds with a forward voltage up to 20v (so for example 10 red leds in series, each with ~ 1.8v forward voltage) and the maximum current is up to 100mA per channel.

 

[Unimportant]

On 9/29/2017 at 4:31 AM, iamdarkyoshi said:

You can use a several 555 timers but by that point, you might as well buy a 1$ controller on ebay...

Or one 555 timer to supply the master clock (triangle-ish waveform can be snooped at the 555's capacitor when operating as a square wave generator) and a comparator + potentiometer for each channel to form a voltage controlled PWM. Somehow seems nicer having everything run to the tune of 1 clock - Also can be controlled with a dc voltage coming from anywhere in stead of being tied to a pot.