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ASSEMBLY.md

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PCB Assembly Instructions

Please read all these instructions. There is important information in here that might not be immediately obvious. It is possible to solder connectors on the wrong side and end up with an invalid setup - pay close attention!

If you use a very hot soldering iron, take extreme care not to melt any of your connectors! I personally use my iron at 310°C with no issues.

Step -1: Buy components in advance

For a list of required and optional components, please see HARDWARE.md.

Have everything? Let's begin!

Step 0: Verify your ESP32 board before soldering anything

Test and confirm your ESP32 works! Go to SOFTWARE.md and install all the appropriate drivers, software, etc. and upload an example sketch to your board! Since the auto-bootloader capacitor isn't connected, you will need to hold BOOT for 2-3 seconds during the Connecting... phase. Once you have confirmed you can upload to your ESP32, you can proceed to assemble the hardware!

Step 1: Mount output connector onto the PCB

Choose your output mode and seat your output connector accordingly.

Output Mode 0

Directly plug this PCB into your LED panel using 2x8 female pin headers. Here's how this mode would look when you're done:

Output Mode 0 Example

Here's how to mount your pin headers for Mode 0:

Assemble Output for Mode 0

Output Mode 1

Connect this PCB to your LED panel via 16-pin IDC ribbon cable plugged in to a 16-pin IDC socket. Here's how you would plug into your LED panel in this mode:

Output Mode 1 Example

How to mount your 16-pin IDC socket for Mode 1:

Assemble Output for Mode 1

Note: the missing edge on your IDC socket should face towards the unused Mode 0 column. Orientation is important!

Step 2: Solder output connector joints

Flip over the PCB and solder your connector's joints

Step 2

Step 2.5 (optional): Solder auto-bootloader capacitor

Technically, you're supposed to hold down BOOT button when powering on the ESP32 to enter bootloader and upload new code.

With this capacitor, you won't need to press anything. Your ESP32 will enter the bootloader automatically and the sketch will upload fine. I recommend this option!

Without this capacitor, you'll need to hold down BOOT for ~3 seconds when Arduino's console reads Connecting...... otherwise the ESP32 will not enter the bootloader and your sketch upload will time out.

If you'd like to add it, solder a 1206 SMD 10uF Ceramic Capacitor to C2. This type of capacitor is not polarized, so the orientation does not matter. I've also had success with a 1uF capacitor, so I don't think the value needs to be exact. It's easy to solder by hand: just add some solder to one pad first, then use tweezers in one hand and your soldering iron in the other. After you finish soldering one half, you can ditch the tweezers for your solder and complete the other side.

Bootloader capacitor

If you don't have a ceramic capcitor, you can solder a 10uF electrolytic capacitor to the pads. Check your polarity! Keep in mind you will place the ESP32 on top in a moment. I would suggest that you run the long legs of the capacitor pins out from under the ESP32, off the edge of the PCB. However, you might also prefer to leave the capacitor in place and increase the height of the sandwiched PCBs.

Alternative bootloader capacitor

Step 2.99 (optional): Apply waterproofing

This is your last chance before your currently soldered components get covered up by the ESP32 board. If you want to apply silicone conformal coating to those joints, now is the time. Also, consider what parts underneath the ESP32 itself will be inaccessible soon, and conformal coat there as well.

Step 3: Seat ESP32 into the PCB

I recommend seating your ESP32-DEVKIT-V1 as close to my PCB as possible. This minimizes the vertical space required. If you bought your ESP32 from AliExpress, you might have to solder the header pins on - remember to ensure they are properly straight (90 degree angle with the ESP32 PCB) before soldering too many!

Step 3

If you want to be able to detach the ESP32, you can attach two 15-Pin Single Row female pin headers instead. Keep in mind this increases the overall height of the device.

Step 4: Solder ESP32 pins onto the PCB

Flip over the PCB and solder the ESP32 pins (or pin headers, if you want to easily detach the ESP32).

Step 4

You can optionally trim the pins after soldering, if you want.

Trim pins

Step 5: GPIO pins

At this stage I would recommend adding in any buttons, switches, sensors, etc. you'd like to add. You can attach these to the breakout pins in the corner! You can add/modify these later too, I just think it's easiest to do this now (just in case you add the C1 capacitor - things start to get crowded!).

If you aren't sure what you'd like to add yet, I would recommend adding female pin headers to all these pins (combine three 1x5 headers). Then you can use dupont connectors to prototype your design!

The following pins are broken out from the ESP32-DEVKIT-V1: D13, D14, D23, D32, D33, D34, D35, D36, D39. All pins but D23 can perform analog reads with 12-bit precision. Remember the ESP32 pins can only handle 3.3V logic! Pin reference: ESP32-DEVKIT-V1 PINS

The silkscreen labelling the GPIO pins is a little difficult to read sometimes, so here's a high res picture of the labels:

GPIO pins

The 3V3 pins carry the 3.3V power from the ESP32's LDO. Please note: the LDO regulates a max of 1A, and that is shared across the ESP32 and these pins. Expect to pull < 0.5A from these 3V3 pins altogether.

In a pinch, your sketch can make use the BOOT button on the ESP32-DEVKIT-V1. It's connected between D0 and GND. This might interfere with your auto-bootloader, requiring you to hold the BOOT button when plugging in your ESP32 in order to program it.

Step 6: Power flow

Let's figure out the best way to power your ESP32 and LED panels! Head over to my power document: POWER.md!

If you haven't used the C1 pads for supplying some power, you can optionally attach and solder a 1000uF through-hole Electrolytic Capacitor. Take note of the polarity! The (-) terminal on the capacitor should be painted white and have printed negative signs. That white side should line up with the white print on the PCB when you insert the capacitor. This capacitor will help prevent brownouts/restarts caused by voltage sag when your panels light up bright suddenly. You can also fold this capacitor down if you want to reduce the vertical space it consumes.

You may also attach the optional screw terminals at this point. These screw terminals simply make it easier for you to connect power to/from the ESP32. You may find it helpful to use some blue tack to help orient the screw terminals as you solder them in place.

Screw terminals

If you only have one screw terminal, you can still fit it between 5V and GND, so you have one pin of each!

Step N-1: Testing and uploading code

Test and confirm everything works! For links to software I recommend using with this board, please see SOFTWARE.md!

Step N: Reinforcing Micro-USB, Waterproofing, hardening

Go crazy with E6000 or your preferred epoxy! I haven't had any issues with this Micro-USB port, but please reinforce it nonetheless! Take care not to accidentally fill the inner part of the port! Add silicone conformal coating if you would like to waterproof anything!

Mission Complete!

When you're done assembling, it should look something like this:

Assembled Front

Assembled Back

Attaching to your LED panel

Attach your PCB to the LED panel like this for Output Mode 0:

Output Mode 0 Example

Attach your PCB to the LED panel like this for Output Mode 1:

Output Mode 1 Example