This is my first post on the forum and also the beginning of my adventure with electronics, circuits and so on. Well, a couple of years ago I built my first small and simple control panel, based on Teensy with several switches and momentary buttons.
Right now I'm working on the second one, based on Mega2560 and much more complicated. There are some things I can't understand. Just a black magic for me and since I'm newbie, any guidance would be appreciated.
My goal is to make one circuit which will be powered with 12V 3A 36W power supply (the one that came with 5m of RGB strip) and it will contain three different types of light sources.
1m or (if possible) 2x1m 5050 RGB 12V strip (60led/m)
7x RGB diodes (built in in momentary button)
19x white LEDs (built in in momentary button, separate leads, common cathode)
Brightness control: potentiometer
Color control: PWM pins
The problems/uknown I'm facing now are:
- One information I'm not sure if I understood correctly while reading in other place so I will ask for confirmation. If I deliver power to MEGA2560 through power jack, does it mean that I can use VIN as an output and provide throught this pin as much of voltage as power supply can deliver (minus what other pins on controller will consume)? Am I getting this right?
- How do I connect all of them together by delivering enough voltage, using just one potentiometer and as less PWM pins? I looked at the diagram at adafruit.com to understand how to connect RGB strip because it was my biggest concern. Transistors used there are NPN TIP120. Then I modified it (picture below) by adding additional RGB and LEDs (only 3 on the pic below) to see how I willl wire them together but then realized that if I connect 19 LEDs to one PWM pin, they won't get enough voltage.
How can I connect these LEDs to get enough voltage and still control it with the same potentiometer as RGB? Can it be actually done?
3. If the answer to above question is "Yes, it can be done", what is the proper way? Could you show me how to do it on breadboard diagram, eventually schematic, although the first one would be easier for me to understand what I see.
Now, some specifications I found.
I don't have datasheet from this particular product.
The info I found from different company for product which looks in close up pretty much the same:
Working Voltage / Input Voltage / Voltage Forward: 12V DC
Power Consumption (Watts) Max.: 5.85W /m 29.26W /5m Reel
Current Draw / Input Current / Current Max: 2438mA 2.44A per 5m Reel
From the strip I have, I was able to read the value of resistors used. These are:
1x331 (1x330 Ohm)
2x151 (2x150 Ohm)
And here the close up picture.
Buttons with RGB:
Current rating :100mA
Voltage rating :12VDC
LED lamp working voltage:
Dielectric withstanding voltage :250VAC for 1 minute
Contact resistance：200mΩ Max. (Initial)
Insulation resistance :100MΩ Min.
Below the diagram for these buttons. Please, notice that those buttons have two separate diodes but only one will be used in this circuit.
Buttons with LED:
Current rating: 50mA
Voltage rating: 12VDC
Dielectric withstanding voltage: 250VAC for 1 minute
Contact resistance: 100mOhm Max. (Initial)
Insulation resistance: 100MOhm Min.
Once again, I appreciate the help.