However, on small brightness levels the colors connected to pin 5 and 6 start to visibly flicker!
While when connected to pin 10 and 11 it works totally fine.
The problem is, I want to control the stripe together with an IR remote but the library uses TIMER2. That makes pin 3 and 11 virtually occupied.
So I only have pin 5, 6, 9 and 10 available - while 5 and 6 flickers.
*Edit: I figured they do not only flicker because of the brightness level but also because pin 5/6 and 9/10 are not synchronized with each other.
That means blue on small brightness (pin 6) does not flicker, green on small brightness (pin 9) does not flicker as well but when mixed together, cyan does seem to flicker.
What are those black things?
If MOSFETs I miss a pull-down resistor. I also miss current limiting resistors on the gate.
If BJTs of course no need for the pull-down but you really need a current limiting resistor on the base.
wvmarle:
What are those black things?
If MOSFETs I miss a pull-down resistor. I also miss current limiting resistors on the gate.
If BJTs of course no need for the pull-down but you really need a current limiting resistor on the base.
Those are IRLB8721 MOSFETs Logic Level, the blueprint is from Adafruit.
This is my first project, I have no experience either with transistors or MOSFETs but it works like that. I believed they know what they are doing.
AFAIK MOSFETs are voltage controlled, aren't they? Why would they need a current limiting resistor?
Regarding the pull down resistor: It is strange, when I disconnect the cable the gate can't pull down. For some reason though, it pulls down when connected to the Arduino.
MOSFETs are voltage driven - their gate acts like a small capacitor so the charging/discharging of the gate causes current spikes. That's why you put a resistor between gate and Arduino pin.
When the Arduino starts up all pins are set to INPUT, so the gate of the MOSFET is floating. The MOSFET can be on, off, partly on... a pull-down resistor on the gate ensures it's guaranteed off.
