Why is my RGB led strip giving lots of problems? Answered
I'm working on project with RGB LED strips with my arduino and a ATtiny84. Basically, what I plan to do is attach the strip to my display cabinet and attach the strip to an ATtiny84 microcontroller which will program the lights. Doing this I have encounter a few problems. As I haven't receive my ATtiny84 chip from the store yet, I'm testing everything on my arduino first. I first attached a normal single RGB LED to test all my programs and it works almost fine.
My first problem was when I attached 3 potentiometer(pot) to the arduino to control the intensity of each pin(red, green, blue). It did as it suppose to. When I turn the knob the brightness increase but as I'm reaching its maximum it drops back low again. So basically as I turn the knob gradually increasing, the brightness increase gradually from zero to it brightest then drops. I have attached a screenshot of this program below. I think it may be the connection between the pot and the arduino as they are quite sensitive but I'm not sure.
My second problem is when I replaced the single RGB LED with the RGB strip, MOSFETs(TIP120) and an external 12V supply it worked like before. I attached a couple of pictures of the layout below. However, when I set all the pins to low brightness the red and blue is turned off but the green led did not. The green led is dim but not completely turned off like the others. Why is this so? I'm very sure its not a defect in the strip. I hv also a attached a picture below of it.
My third problem is when I bought the three MOSFETs from the store I got one slightly different one although with the same label of TIP120. I have also attach a picture of the MOSFETS below. The pin that is connected to this different MOSFET seems to act the opposite of its values. As in when I set that pin to low brightness it will be bright and vice versa unlike the other two. I can easily buy another one but I would like to know why this happens.
This is not really a problem but more of a question. As you can see I attached a 1k ohm resistor between the MOSFET and the arduino output to limit the draw of current. I would like to know what would you recommend the value of the resistor because I do not want to damage my chip. Is 1k enough?
My second question is I'm using a 12V 2A power adaptor as my power supply and a L7805 voltage regulator to provide a 5V power for my ATtiny84. However when I connect it I do not get a stable output and its value is around 5.3V. According to some videos I should attach a 0.1 microFarat electrolit capacitor to the input and a 22 microFarat electrolit capacitor to the output in parallel, however when I do so my output is still not stable and is around 5.8V which is too high for the chip as the max Vin for the chip is 5.5V. So what should I do?
My third and last question is my power adapter heats up when its powered but not connected to the circuit. Why is that? And my MOSFETS and voltage regulator gets hot occasionally. Should I attached a heat sink? Is this circuit possible to be left on 24/7? and how much power will it consume?
Sorry for the long post, I'm fairly new to electronics and I'm just a student who is trying to learn electronics on my own. I have been working very hard on this project and I hope I get the best out of it. Sorry for the bad english too. Any help and comment will be much appreciated.
Thank you very much!!