Hello,
First of all, selecting NSI50350ADT4G is a wrong decision as it is a linear converter. That means any unused energy is consumed on this IC and produces a lot of heat. When the temperature reach the thermal shutdown threshold, it reduces the current. Usually, the higher the input voltage, the hotter the IC is.
To make the system run in more effective way - and so, it's much less warm, you should use a buck converter. Basically, the circuit tries to get just enough energy from the source and feed to the led using PWM. You can easily recognize the buck converter when you see an inductor on the circuit.
Long time ago I used LM2596 to drive the leds. Today, it's much easier with IC such as BP1360 or
ready-made module such as this one [login to view URL]
Scope of my bid are:
1. Design the circuit using BP1360 IC and the board is going to control by Arduino. I will send you the schematic + wiring diagram.
2. Write a small Arduino code to read 1 input from N/O switch and turn on R, G or B when the switch is press (i.e. press 1st time: R, 2nd time G, 3rd R and 4th back to R).
The bid does NOT include the cost to make the prototype nor shipment. It cost about $200 more to make a prototype board and ship from Vietnam to UK (both making prototype + shipment) so please let me know if you want to go with that.
Regards,
Anh