Andong:
Hi all. Recently started building a lightsaber using all the usefull info and tools everyone kindly shared but after some testing and couple burned hp-leds i've got couple questions:
In the schematics you use 100k resistors but i didn't find any notes if it's supposed to be 0.5w, 1w, 2w or any other?
I tried single 18650 battery with dc-dc step up connecting it to 5v pin on arduino but it doesnt seem to work, well it powers up but instead of normal sounds the df player starts to produce some crackling sounds. So i switched to 2x16340 to get 7.4-8.2v. As for mosfets i tried 2 different types
I would advice you to grab a DIYino Prime board instead of expermenting. Proven, reliable and you can focus on programming the effects you would like to have.
As to the supply scheme you used, with a single 18650 (3.7V) battery you will be very close to undervoltage for most of the chis on board. If you on top of it turn on the LEDs, which causes a substantial inrush of current, ground shift and IR drop over the wiring will cause the voltage to drop even further. I also know from expeience that the first module which will fail to work is the audio amp, hence the crackling sounds. I made once a E11 blaster using a single cell, works, but there I have only small burst of lights whereby in a lightsaber the lights are continuosly on.
In terms of mosfets, it's important to select those which can carry a min of 2A, low Rdson and logic level (meaning a Vgs threshold not greater than 2.5V). If the Vgs is close to your battery, the fets are not fully in which could explain the dimness. And if your red LED will switch on earlier than the blue and greed due to a lower threshold, it could "steal" the current from the other 2 if your battery cannot supply enough current for all 3.