In the previous video, we prototyped our LED driving circuit.
In this video we will build out the complete schematic for our Moon Lamp.
And in the followup video, we’ll layout our PCB and send it off for manufacture with JLPCB.
I’ve started a new project in EasyEDA and we’ll start to build our schematic.
I’ve already looked up the parts that I want to use, so let’s get started!
I’m going to power the moon lamp from a 5v USB power supply so the first thing we
will need is a 3.3v regulator.
We’ll use the AMS1117-3.3 which is a basic part on JLPCB.
We’ll also need to add some capacitors to the input and the output of the regulator.
So let's add those components and wire them up.
We'll also need a way to get power onto the board so we'll add a screw terminal.
So that's our power regulator finished.
Let's move onto our ESP32 Wroom module.
It’s recommended to add a decoupling capacitor close to the power input to this module so
we’ll add a 10uF capacitor.
It’s also recommended to add an RC circuit to the enable pin so that the module is disabled
while the power supply stabilized.
We’ll add a 12Kohm and 100nF capacitor.
That's our ESP32 module all wired up.
For the output drivers, we are going to need a MOSFET.
JLPCB has a basic part that will serve our needs so we’ll use this.
We also need a gate resistor, a pull-up resistor and the LED resistor.
We'll have a 470 ohm gate resistor and a 470 ohm pull up resistor.
And for the LED resistor we'll use a 1 Watt 5.1 ohm resistors.
So we'll wire this up now.
Let’s also wire up GPI02 to an LED so that we can do a simple blink sketch to test our
PCB when it arrives.
We'll put in an LED and a resistor and connect that to GPIO2.
It’s probably also handy to have some indicators that that we have power coming into the board
so we'll add a connection to the 5v the 3.3v regulator so we can see it is working properly.
I’m not including a USB to serial chip, we’ll use an external USB to serial chip.
TX and RX are both active low and it’s handy to see if they are doing anything.
So we'll wire up TX and RX to an LED as well.
Let’s also expose out all the GPIOs so we can expand our board if we need to.
So let's put in some headers.
That’s our schematic all done.
In the next video, we’ll lay out the PCB and send it off for manufacture with JLPCB.
We'll probably change the ordering of these pins and these pins to make it easier to lay
the board out.
But it should be a fairly straightforward board.
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And I'll see you in the next video.