Digital LED Candle
Posted: Sat Dec 14, 2019 5:14 pm
I have always wanted to make my own digital LED candle. Since I am currently in Shenzhen, China - the
capital of the world for electronics, I thought it could make a quick simple project to do here. No
real pre-project specs, just that it must have multiple LEDs and use side-lit fibre optical cable.
The seven story HQB LED building has a store that sells optical fibre up on the 6th floor, so I popped
in and purchased a few different thicknesses of side-lit fibre. Also picked up three different
coloured 5730 size (1/2 Watt), LEDs to test.
Due to the high current that might be needed to light up the LEDs to full brightness, I decided to use
some common AO3400 NPN MOSFETs to buffer the Arduino and switch the LEDs on/off.
I wanted to see what the LED's looked like when they where coupled to the side-lit fibre, so I
purchased some two part epoxy glue form the local tiny hardware store (called AB Glue here): The initial circuit ended up with a MOSFET pin error, as KiCAD doesn't have a AO3400 MOSFET in it's
native library. I fixed one MOSFET by cutting it's PCB traces and re-wiring it the correct way around: It didn't take long to fix the errors in KiCAD and add on a six pin T1.25 SMD socket onto the PCB and
version 1.1 was off to https://jlcpcb.com for production. It takes around four days to
produce a cheap board. You can pay extra to have one manufactured in 24 hours, but I wasn't in a rush.
It didn't take long to hand solder the components into place:
capital of the world for electronics, I thought it could make a quick simple project to do here. No
real pre-project specs, just that it must have multiple LEDs and use side-lit fibre optical cable.
The seven story HQB LED building has a store that sells optical fibre up on the 6th floor, so I popped
in and purchased a few different thicknesses of side-lit fibre. Also picked up three different
coloured 5730 size (1/2 Watt), LEDs to test.
Due to the high current that might be needed to light up the LEDs to full brightness, I decided to use
some common AO3400 NPN MOSFETs to buffer the Arduino and switch the LEDs on/off.
I wanted to see what the LED's looked like when they where coupled to the side-lit fibre, so I
purchased some two part epoxy glue form the local tiny hardware store (called AB Glue here): The initial circuit ended up with a MOSFET pin error, as KiCAD doesn't have a AO3400 MOSFET in it's
native library. I fixed one MOSFET by cutting it's PCB traces and re-wiring it the correct way around: It didn't take long to fix the errors in KiCAD and add on a six pin T1.25 SMD socket onto the PCB and
version 1.1 was off to https://jlcpcb.com for production. It takes around four days to
produce a cheap board. You can pay extra to have one manufactured in 24 hours, but I wasn't in a rush.
It didn't take long to hand solder the components into place: