After soldering the 1206 SMD resistors, it was time to test the board. Note that this is a direct drive circuit where I connected the LEDs directly to the LiPo battery. I took the temperature reading after a few minutes. The simple IR temperature thermometer registered about 47.2ºC which to me, is quite high.
On the second test, I used a LED Driver. This 9W module accepts voltages from 3.3V to 6.0V and pumps out a constant current of 1.5A or less, and you can only connect to a maximum of about 16 LEDs. The temperature dropped to about 39ºC. So, this is not too bad. Perhaps if I used the 1/8W though-hole resistor, things might not be so worrying. This would mean another PCB re-design to house all 5 of these clunky components.
I reduced the Xioami 14T Pro’s exposure to show you the hot spots caused by the 020 SMD LEDs.
This is the normal view you’d see. Unless you want to cut away the plastic, you can light block the whole part, leaving only the gap for backlighting. I will change the middle LED from 5mm to 3mm later.
This is the PWM Module aka LED Driver. Note the resistor was positioned to only halfway.
